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Ecological corridors and buffer zones 1

The Wider Landscape for Nature Conservation:ecological corridors and buffer zones

MN2.7 PROJECT REPORT 1995submitted to the European Topic Centre for Nature Conservation in

Fulfilment of the 1995 Work Programme

edited by R.H.G. Jongman and A.Y. Troumbis

European Centre for Nature Conservation

This Report includes an updated version of the discussion document for the workshopmeeting at the Centro González Bernáldez in Soto del Real (Spain):Troumbis, A.Y., Farjon, J.M.J., Miklos, L., Mugica, M., and Jongman, R.H.G. 1995.Buffer zones and Ecological corridors. A Report to the European Topic Centre for Nature.


Content

1 Report of the Working Group..........................................................................................41.1 Introduction ..................................................................................................41.2 The project team and the work process .......................................................41.3 The general framework of the project..........................................................61.4 Corridors and Buffer Zones .........................................................................71.5 Core areas and their environment................................................................7

1.5.1 European policy.................................................................................71.5.2 Spatial strategies for nature conservation ........................................91.5.3 Buffer zones .....................................................................................131.5.4 Ecological corridors.........................................................................15 1.5.5 Implementation ...............................................................................17

2. Spatial strategies for nature conservation. ............................................................212.1 Introduction ................................................................................................212.2 Nature conservation and physical planning in The Netherlands .............222.3 Nature conservation and landscape ecology in Slovakia ..........................252.4 Nature conservation and land use in Madrid Region, Spain ...................272.5 The nature conservation directives of the European Union......................27

3 Buffer zones ............................................................................................................293.1 Definitions ...................................................................................................293.2 Multifunctionality of buffer zones..............................................................303.3 Buffer zones in the European experience: case studies .............................33

3.3.1 The landscape approach: zoning system for protected areas ........33..........................................................................................................343.3.1.1 The National Park of Abruzzo (Italy). ................................353.3.1.2 The Regional Park of "Cuenca Alta del Manzanares", Madrid

region, Spain ........................................................................363.3.1.3 The Marine National Park of Vories Sporades, Greece. ....37

3.3.2 Habitat-based design and ecological function(s) of buffer zones 403.3.2.1 Water retention in Northwestern European wetlands and

water fed ecosystems............................................................403.3.2.2 Nutrient-buffer areas in The Netherlands ..........................433.3.2.3 Hydrologic buffer zones in the National Ecological Network of

the Netherlands....................................................................44

4 Ecological Corridors...............................................................................................464.1 Definitions ...................................................................................................464.2 Ecological and spatial aspects of ecological corridors................................474.3 The European experience in designing ecological corridors: case studies 51

4.3.1 Possible ecological corridors in mountainous national parks inFrance. .............................................................................................51

4.3.2 Ecological corridors in the National Ecological Network of MetropolisCentral Netherlands. .......................................................................51


4.3.3. Landscape elements as corridors and buffer zones in Madrid region,Spain ................................................................................................55

5 Criteria and procedures .........................................................................................625.1 Ecological networks in Europe ...................................................................625.2 Implementation of ecological corridors and buffer zones ...............................645.3 Procedural guidelines..................................................................................665.4 Planning challenges.....................................................................................68

6 References...............................................................................................................73

Annex 1...............................................................................................................................76

Annex 2...............................................................................................................................77



1 Report of the Working Group

1.1 Introduction

This report is the product of a joint effort of the network members of the ECNC on arequest of the European Environmental Agency to the European Topic Centre for NatureConservation (ETC/NC). The aim of this project is to develop criteria for identification ofecological corridors and buffer zones in support to national activities implementing Natura2000 network. Definitions must be valid and applicable in all European regions andsubregions in ecological context and all countries. This means that Pan-European definitionsand criteria should be developed. It is not possible to cover all Europe within the timeavailable for the project. So it has been decided to emphazise the European Union but alsoto include active participation from Central Europe. The steps in the project have been:1 Preparation of a discussion document to guide an international workshop on

ecological corridors and buffer zones on the potential role and expected results ofconcepts on ecological corridors and buffer zones in the context of national andinternational nature conservation policies based on existing practical experience onecological corridors and buffer zones designation in relation with the concernedprotected area systems.

2 In a preliminary meeting a proposal has been made on coherent and widely validdefinitions of ecological corridors and/or buffer zones at the European level. In thispreliminary meeting it has been concluded that criteria are difficult to assess nowbecause of the early phase of international cooperation. However, procedures fordecision making and planning could be proposed.

3 An international workshop on ecological corridors and buffer zones has been heldat the Centro de Investigaciones de Espacios Naturales Fernando GonzálesBernáldez in Soto del Real (Spain) to discuss the discussion document and to findan agreement on:definitions to be used at European level for ecological corridors and buffer zonesconcepts,practical and applicable procedures and criteria for identifying, if appropriate,ecological corridors and buffer zones by the different European countries.

This report is the result of the workshop in Soto del Real and it reflects the status ofknowledge at this moment.

The fundamental assumption of this document is that Natura 2000 sites are representativesamples of Europe's biodiversity. Species, their biological characteristics and ecologicalprocesses within the sites have to be subjects of protection and management in order toform a stable ecological network according to the previsions of the Habitats Directive.

1.2 The project team and the work process

The project team consists of laboratories that work in this field and that representEurope's geographical diversity:


* The Centro Fernando Gonzalez Bernaldez (CIFGB) in Soto del Real, Spain;* The Biodiversity Conservation Laboratory (BCL) of the University of the Aegean

in Mytilene, Lesbos, Greece;* The Winand Staring Centre, (WSC) of the Dutch Directorate of Agricultural

Research, Wageningen, The Netherlands;* The Unesco chair on nature conservation awareness of Banská Stiavnica, Slovakia;* The secretariat of the European Centre for Nature Conservation (ECNC),

Tilburg,The Netherlands, that is responsible for coordination and the final editing.In the course of the process active support has been given also by English Nature thatcarried out a long term literature research to ecological corridors. They participatedactively in the process and substantially contributed to this report.

The first phase was a description of the potential role of buffer zones and corridors in thecontext of national and international nature conservation policies. We interprete this as adescription of the ecological role of buffer zones and corridors (their function and theirimportance) in relation to national and regional nature conservation policy. This cannotbe done for all European countries, so a selection has been made based on the knowledgeof the partners in the project and available sources.

A review on the existing practical experiences can only be produced by using examples onthe different types of buffer zones and corridors of which research data are available. A fullreport on this can only be produced if sufficient monitoring data are available. Time anddata are restricted so only examples will be given.

The role of buffer zones for the core area and the existing knowledge on species exchangethrough natural and man-made corridors has been analyzed by the partners. Every partnerdeveloped his/her own definitions of ecological corridors and buffer zones based on thetypes of corridors and buffer zones they analyzed. This has been done to prevent that oneinstitute would dominate the definition phase. In the final document these definitions havebeen compared and brought together into one definition.

The partners tried to identify examples of protected areas, systems or situations whereurgent actions are needed. However information on this is not widely available to give anunbiased overview. Further research, interviews and analysis of management plans andland use planning systems might be needed to identify actual and potential hazardousareas.

Based on the above procedure the project team proposed criteria for ecological corridorsand buffer zones. They met in a preliminary workshop on 15 September in Tilburg tofinalize the results of their contributions and to propose procedures and criteria forecological corridors and buffer zones (Annex I). The results have been presented at theworkshop in the 2 and 3 November in Soto del Real (Spain) and discussed with expertsfrom many European countries (Annex II). This report is the reflection and the conclusionfrom this process. It contains the conclusions from the workshop on 2 and 3 November andreflects the status of the scientific knowledge that is available now.


1.3 The general framework of the project

The work for the nature conservation policy development in Europe is multi-facetedapproach. It deals with biodiversity assesment, support for Natura 2000 and a generalapproach for nature conservation in Europe (Wascher et al, 1995).

In the first year the assessment of Europe's biodiversity and nature conservation is thetheme of workshops and start-up activities of the ETC/NC. The participants of thesemeetings and discussions are qualified experts from well-known European researchagencies. These experts based their views and opinions on information that represents latestresearch results and philosophical concepts on biodiversity as a scientific discipline, as apolicy-instrument as well as a data management objective.

Several workshops have been held on biogeographic aspects of Europe's biodiversity.Ecological values of Northern and Western regions are often determined by aspects suchas species abundance, presence of rare and threatened species, functional integrity andcoherency (connectivity) of natural habitats as parts of complex (cultural) landscape-systems. The studies describing Mediterranean and Alpine ecosystems underline the roleof species richness and endemism as significant properties. Biodiversity can be defined asvariety in genetic information number of species. In nature conservation it is commonlyassociated with species richness, the number of species within an area (Dodd, 1994). It canbe concluded that any prioritization for (especially absolute) numerical aspects ofbiodiversity (richness) does not correspond with the observed characteristic properties of the natural environment. Mediterranean Europe has a high species richness in general.Northern and western parts of Europe have a greater richness in special ecosystems andspecies e.g. bogs and amphibians. The workshop on biodiversity in Wageningen (TheNetherlands) concluded that the identified regional characteristics point at the need for anadequate biogeographic classification and for a set of assessment criteria that reflect andbalance all observed ecological properties.

The methodological approach that came out of it was that a holistic approach should beintroduced in traditional nature conservation. As Lovejoy (1995) commented:"Biodiversity in essence represents the most fundamental library in support of the lifesciences: tens of millions of species with unique sets of properties, processes and 'solutions'to unique sets of biological histories and challenges". As such, the concept of biodiversityis expected to be complimentary, integrative and supportive towards the objectives ofnature conservation and vice versa. The international experts present at the WageningenWorkshop agreed that a methodology to "assess the state and trends of biodiversity" cannot be restricted to solely aspects of richness but needs to take into account criteria suchas rareness, representativeness, naturalness, connectivity and abundance for not onlyspecies and habitats but also for the larger context of landscapes. The inclusion of ‘landscapes’ as one of the basic corner stones of a European biodiversityassessment is principally based on the diversity of traditional agricultural landscapes andrelated species richness in Europe and its critical role for a sustainable future. While


European nature conservation legislation is focusing on some of the most important key-areas for rare and endangered species and habitats, the remaining large areas - dominatedby agriculture and forestry - are exposed to an ever increasing intensification or to changesof management regimes that devalue their long-term economic potential while at the sametime loosing important environmental functions for Europe’s nature and wildlife. BirdlifeInternational (1994) noted that «despite the recent reforms, the Common AgriculturalPolicy (CAP) is still one of the most damaging influences on the rural environment due tohabitat destruction and pollution.» The issue has also been addressed during the worldconference of the International Association for Landscape Ecology in Toulouse (August 27-31, 1995) which came to the conclusion that the existence of direct relationships betweenlanduse changes and diversity changes is suggesting that the future landscape diversity canbe directed by acting upon the driving forces of landuse changes, with particular referenceto common policies of the EU, especially the CAP. This view is supported by manyenvironmental reports, including the EEA’s latest publication «Europe’s Environment -The Dobris Assessment» which documents the role of landscapes for a sustainabledevelopment (Stanners & Bourdeau, 1995) and the Council of Europe’s «EuropeanBiological and Landscape Diversity Strategy».

1.4 Corridors and Buffer Zones

The role of landscapes to support nature conservation areas is more and more recognized.Population dynamics and landscape ecological theories indicate that many species can notsurvive in isolated reserves. For many these are too small or are only of use during a certainperiod of their lifecycle. Moreover land use around conservation areas can influence theenvironmental conditions inside. The Habitats Directive (EC92/43/EEC) and BirdsDirective are the major coordinating instruments at the Community level. In Article 3 ofthe former, Natura 2000 is proposed as a coherent structure for nature conservation areas.To strengthen the structure of Natura 2000 article 3c proposes the conservation of linearand continous features as corridors. In article 10 this is elaborated as the responsibility ofnational governments. This conservation must be seen in the context of favourableconservation status as formulated in article 11 of the Habitat Directive.

Ecological networks consist of core areas, buffer zones and corridors as links between theseareas. The core areas are the centres of biodiversity or centres of special importance forcertain species or species groups. In many countries they have a protection status. For thewell functioning of core areas in a network, measures in the wider landscape might beneeded. These can be buffer zones to prevent negative influences and corridors that maybe necessary to provide exchange between them, to prevent genetic erosion, for foraging,for population growth and for colonization of empty habitats or formerly non-suitablehabitats due to succession or environmental change.

1.5 Core areas and their environment

1.5.1 European policy


For the analysis of supporting areas for core nature conservation areas it is important toknow the position and the role of core areas first. Core areas and the species in them canbe supported by measures in the wider landscape. The Habitats Directive indicates thatSpecial Areas for Conservation are sites of Community importance designated by the memberstates through a statutory, administrative and/or contractual act where the necessaryconservation measures are applied for the maintenance or restoration, at a favourableconservation status, of the natural habitats an/or the populations of the species for which thesite is designated. The conservation of a natural status is favourable when- its natural range and the area it covers within that range are stable or increasing and- the specific structure and functions which are necessary for its long term maintenance

exist and are likely to continue to exist for the foreseeable future and- the conservation status of its typical species is favourable.The conservation status of a species is favourable when- population dynamics data on the spesies concerned indicate that it is maintaining itself

on a long-term basis as a viable component of its naural habitats, and- the natural range of the species is neither being reduced nor is it likely to be reduced in

the foreseeable future, and- there is, and will probably continue to be, a sufficiently large habitat to maintain its

populations on a long term basis

Spatial transition from one biological community to another has attracted the interest ofecologists, geographers and wildlife and land managers for several decades. 'Ecotones','buffer zones' and 'natural corridors' (and related or synonymous concepts) are conceptsrelying on the idea of transitional zones between ecological units. These concepts for natureconservation have recently been enriched by recognizing their value regarding biodiversitymaintenance and control of flows across the landscape. A landscape is a network of patchesor habitats connected by fluxes of air, water, energy, nutrients and organisms. Interactionsbetween habitats are thus defined by these landscape fluxes and the function of the latterfor certain habitat-conditions.

In theory, corridors are self-defined landscape elements generated through contact ofdistinct ecological units. Landscapes and/or landscape elements could become a buffer zonein relation to an area for conservation after the application of a management plan or landuse regulation.

If an area is a Special Area for Conservation for Natura 2000 (SAC), being representativesamples of Europe’s biodiversity, however, does not mean that it stands alone. It shouldfunction as a optimal habitat for the species concerned and function without disturbancesfrom the outside. They should even function for the wider environment as a source andrefuge area for species. That means that linkage with the wider landscape is essential. Thisalso means a link with policies for the wider countryside; policy and planning for thesupporting areas means also linkage between nature conservation, agriculture and therealization of road and railway networks. Here integration between national and Europeanpolicies is vital. Agricultural policy can harm or favour buffer zones by its financial andjuridical instruments and transport planning can mitigate its impact by including thepersistence of ecological corridors in the project.


Buffer zones and ecological corridors are management objects which may be necessary toensure the conservation status of species and habitats within the Natura 2000 sites. Thefollowing flow diagrams (I, II and III) present the logical paths for analysis of ecologicaland biological data which are necessary to assess if the full range of functions a landscapeor marine area needs to be capable of fulfilling to achieve favourable conservation statusfor the species involved is covered. There is a need to consider features required acrossareas, and set out the overall character of an area which is necessary to achieve favourableconservation status. This will include consideration of the full range of ecological needs ofthe species involved, including movement, dispersal, migration and genetic exchange.Buffer zones and ecological corridors refer to the specific and positive requirements forhabitats to meet the full ecological requirements of particular species so that favourableconservation status can be achieved.

Buffer zones relate to specific sites with particular needs. They should be shown to addressparticular issues that affect the achievement of the conservation objectives for the site. They should be the best means for addressing these issues at the particular site. This mayrequire specific policy support at a wider level, and this should be identified in theassessment of the suite of measures needed to achieve favourable conservation status. Itis important not to use buffer zones site by site when wider policy development is a moreefficient means of securing the conservation goals that have been set out.

The Habitats Directive refers to corridors and stepping stones. We need to be neutral asto shape and extent of corridors: one important contribution they can make is to ensuresufficient habitat to maintain populations across their total natural range.This will requiredecisions on location, management and pattern. This is clearly flagged in the BirdsDirective (article 3(2)(b), (c) and (d)) and is implicit in the Habitats Directive.

1.5.2 Spatial strategies for nature conservation.

Nature conservation strategies based on the designation of particular sites rather than onthe whole territory have not been successful, at least in terms of conservation of biodiversity(e.g. Shafer, 1991). In many ways the conditions within designated areas are influenced byhuman land use. Examples are acid deposition, lowering of water tables, deterioration offoraging and resting areas for animals, disturbance of migrating organisms, inflow of wastewater and disturbance by recreation. A designated area strategy may often proveinsufficient by itself in maintaining and upgrading biodiversity within the designated areasbecause of ecological processes and external influences on larger scales and because theconnectivity between habitats are not taken into consideration for the management of thesite.These influences on designated areas by human activities in their surroundings haveresulted in the need for a spatial strategy in nature conservation (Farjon and Bakker,1995).

Furthermore, habitat and landscape fragmentation negatively affects ecological andpopulation processes. In landscapes in which natural areas are being increasinglyfragmented, maintenance or restoration of habitat connectivity has become a central goalof biological conservation (Noss, 1993). The classic approach in nature conservation, that


is the conservation of target species and other valuable nature features within strictlydelineated protected territories, is currently re-oriented towards the (un)differentiated careof the whole landscape (Miklos et al., 1995))

Two ideas emerge as crucial points in this context. The first is that the limitation, controlor regulation of certain human activities in areas outside designated sites is essential infacilitating biodiversity within a reserve. The second is that there is a hierarchy inconservation objectives generating nested protection levels, necessary for the maintenanceof the stability of the landscape. The major pre-condition for the ecological stability of thelandscape is the maintenance of the spatial relations between ecosystems (of various levelsof stability) through a spatial system of functionally interconnected elements, i.e. a physical ecological network.





An ecological network is composed of core areas, (usually protected by) buffer zones and(connected through) ecological corridors (Bennett, 1991). Ecological corridors and bufferzones have already a history of scientific investigation and application and are becomingkey elements of the 'ecological network' strategy. Ecological networks are more widespreadin Europe than many would suppose (Jongman, 1995). Reviewing recent developmentsconcerning ecological networks, Arts et al. (1995) concluded that "during the last decade,the nature conservation policies in many European countries have been based onlandscape-ecological research, especially concerning the role of land use and landscapestructure in the survival of species and in the protection of nature reserves. Plan proposalswere made to establish ecological networks on local, regional and national scales."

The occurrence of wildlife species within a certain habitat is, amongst others, determinedby five habitat conditions: the optimal availability of water, nutrients, energy, organismsand minimal human disturbance. Within a habitat-network the optimal habitat-conditionis related to a certain steady state of landscape fluxes, such as air movements, water flows,migration and human transport. Within the perspective of landscape fluxes sub-optimalhabitat conditions in a designated area can result from too small or too large in- andoutputs of water, matter, energy, organisms and human influence. Farjon and Bakker(1995) call areas outside designated areas that facilitate biodiversity within designatedareas Nature Facility Areas (NAFA's). NAFA's are defined as those areas which are notdesignated as nature reserves but which have certain limitations to human interference innatural processes in order to facilitate abiotic, biogeographic and social-economicconditions for biodiversity within designated areas.

The nature facility areas often coincide with multifunctional landscapes. These landscapessupport both nature and other land use functions. Buffer zones and ecological corridorsare specifications of these multifunctional landscapes. By changing human influence innature facility areas other parts of the habitat-network habitat-conditions in the core areamay regain their former optimal status. That means that by managing buffer zones andecological corridors the favourable conservation status of habitats and species can besupported. In practice landscape linkage elements, especially ecological corridors, are notyet integral parts of conservation plans Implementation of theory in policy andmanagement practice needs time (Jongman 1995). Knowledge of scientific, political andsocial tradition and history are important in understanding these differences.

1.5.3 Buffer zones

The concept of buffer zones is rather old (Wright and Thompson, 1935). Literature offersa number of definitions, related to the approach used for their design within the frameworkof a spatial and management strategy. Within a hardly anthropocentic view of nature, Jehoram (1993) distinguishes the nature management-approach and the landscape-approach generating different definitions, allocation criteria and management strategiesfor buffer zones. The nature management-approach can be illustrated by the IUCNdefinition of bufferzone: a zone peripherical to a national park/reserve where restrictions areplaced upon resource use or special development measures are undertaken to enhance theconservation value of the area (Oldfield, 1988). The landscape approach is illustrated by the


World Bank definition: a social agreement or contract between the protected area and thesurrounding community, where size, position and type of buffer zone is defined by theconditions of this agreement.

Within the framework of an ecological network strategy, as is the case for NATURA 2000,the definition of a buffer zone should integrate both lanscape and functional attributes. Adefinition based on the ecological function(s) of the buffer zone should focus on the mainmanagement objective (Miklos et al., 1995)a. protection, to protect from the expansion of harmful humanactivities,b. interaction, to sustain positive landscape interactions,c. diffusion, to sustain natural and man-made flows in the landscape.

Landscape alteration outside the boundaries of the core area - a national park, a naturereserve or otherwise designated area - generally causes important biotic changes within theprotected area. Buffer zones intend to maintain landscape elements around the naturalremnant and to avoid abrupt changes by creating environmental gradients. Common sense(and the slowly accumulating practical experience) allows us to recognise that thefundamental role of protected areas would not be achieved if the primary need ofcontrolling adjacent human activities that influence them is not accomplished. Buffer zonesmay be viewed as a shield around the core area against the direct impact of humanactivities. Human activities should be viewed both macroscopically as more or less changingland use, according to their physical dimension as disturbances generating a long series ofabiotic and biotic fluctuations influencing species and communities under protection.

The ideal form of a buffer zone is materialized in the "ring pattern" of UNESCO'sBiosphere Reserves (UNESCO, 1974). According to a concentric zoning design, at least twokinds of rings are defined: the core area (inner ring) contains the biologically mostimportant areas. The next ring(s) is (are) a buffer zone where plans of controlled resourcemanagement are applied, and where traditional cultural activities are permitted (e.g. theouter ring has agriculture).

The participants in the CIFGB workshop stated that although national parks and otherconservation areas are meant to conserve species and habitats, they usually are not withoutimpact of the land use around it or upstream. They concluded that the following definitionof a buffer zone is appropriate:

Buffer zones are areas where the management objectives are aiming at the regulation offluctuations of abiotic, biotic and man-related factors in the land adjacent to a naturalremnant (entire -or parts of- NATURA 2000 sites), designated as a protected area.

This means that buffer zones are intended to serve direct ecological purposes related to theminimisation of the impact of land use activities and the effects of landscape fragmentationand core area isolation. A primary effect of fragmentation is related to changes inmicroclimate within an area and in immediately surrounding natural remnants. Thesechanges provoke alterations to the environmental conditions of the habitat (Saunders et al.,1991). In that case, buffer zones appear as a sensible strategy to seal off core areas fromfurther microclimatic changes.


The shape of the core area is crucial for the accomplishment of several key functions. Anecologically optimum patch shape usually has a large core with some curvilinear boundariesand narrow lobes, and depends on the orientation angle in relation to surrounding flows(Forman, 1995). In that case, buffer zones may play the role of correcting the shape of thecore area. This feature of a buffer zone becomes more and more important as the size of thecore area decreases. In the case of many small - sized NATURA 2000 sites, buffer zonesshould serve as management tools to integrate them efficiently in the landscape functionalflows.

Buffer zones aim at controlling human activities within the adjacent lands to a coreprotected area by promoting their sound management, thus decreasing the potentialimpacts and the probability of isolation. The presence of a local population is implicitelypermitted within the buffer zones (otherwise the buffer zones would be a totally protectedarea). The current approach in buffer zone design tends to accept them as areas where aplan of land-use regulations is applied rather than as clearly defined areas that could havelegal protection. Thus, the buffer zone is (or should be) designed (1) to protect localtraditional land use, (2) to set aside an area for manipulative research and, (3) to segregateland use like agriculture but also recreation or tourism activities, from the core area inorder to avoid adverse effects, and in this way to support direct site management, (4) tomanage adverse effects by putting up a barrier for immediate protection an (5) to locatedevelopments that would have a negative effect on the core area if they were situatedelsewhere.

1.5.4 Ecological corridors

An ecological network is successful if it sustains biological transition and landscapeconnectivity at all levels where fragmentation, isolation and barriers to movements andfluxes are defined. A European ecological network, an international network, shouldintegrate a set of mutually compatible national networks, being completed themselves byregional and local networks in each country. Natura 2000 sites that function as core areasmust inevitably be linked with the wider countryside to allow species dispersion to smallersites. On the other hand species must have the possibility to colonize empty sites within thecore areas if available.

Ecological corridors are various landscape structures, other than patches, of size and shapevarying from wide to narrow and meandering to straight, which represent links thatpermeate the landscape, maintaining or re-establishing natural connectivity. Ecologicallinks between patches have always existed also in natural landscapes. Most obvious aremigration routes for birds, ant-routes, badger routes and river corridors for fish migrationlike for the eel and the salmon. Now most of the ecological corridors are primarily the resultof human disturbance regimes. Their density and spatial arrangement change accordinmgto the human land use. Their connectivity varies from high to low. Nowadays nature needsdifferent types of ecological corridors that have a complementary role to play in aninterconnected habitat island system. Like other land use they need planning.


The term 'corridor' has appeared very early in the literature to refer to long range dispersal(Simpson, 1936). The current use of the term ecological corridor has been recommendedby Preston (1960) who has attributed it significant properties in spatial populationdynamics allowing the increase of size and enhancing the chance of survival of smallerpopulations between preserved patches. The currently expanding field of metapopulationdynamics presupposes that some degree of connectivity exists between the spatiallyarranged subpopulations within the fragmented landscape.The nature of ecological corriodors and their efficiency in interconnecting remnants andin permeating the landscape depend on their origin and the land use mosaic within whichthey are embedded and of which they consist: remnants (hedgerows), spot disturbance(railroad and power line strips), environmental resource (streams), planted (shelter beds),and regenerated (regrowth of a disturbed strip) (Forman, 1983).

Four types of corridors are defined:(1) line corridors, which are narrow strips of edge habitat, such as paths, hedgerows androadsides,(2) strip corridors, with a width sufficient for the ready movement of species characteristicof path interiors (for example, a wide power line corridor permitting movement of opencountry species through a forest),(3) stream corridors, which may function as one of the previous two, but which additionallycontrol stream bank erosion, siltation and stream nutrient levels, and(4) networks, which are formed by the intersection of corridors, this usually resulting in thepresence of loops, as well as subdiving the matrix into many patches.

The participants of the CIFGB-workshop having discussed the different features andcharacteristics necessary to define ecological corridors and agreed on the followingdefinition of ecological corridors in the context of the Habitats Directive:Ecological corridors are landscape structures of various size, shape and habitat compositionthat maintain, establish or re-establish natural landscape connectivity, supporting thefavourable conservation status of species and habitats for which NATURA 2000 sites havebeen designated.

The more complex a corridor is, the more it can be multifunctional. The higherimmigration rate that can help to maintain species number, increase population size,prevent inbreeding, and encourage the retention of genetic variation can be judged as the main advantage of corridors (Simberloff and Cox, 1987). They also increase the foragingarea for wide-ranging species and provide possibilities to escape predators anddisturbances. Of course they also can have negative influences like the breaking of isolationand exposing populations to more competitive species, the possibility of spreading ofdiseases, exotic species, and weeds, and disrupting local adaptations, facilitating spread offire and abiotic disturbances.

To define the need and the criteria for ecological corridors, it is first necessary to definewhat constitutes sufficient habitat to maintain the population of a species. Favourableconservation status means that species should be components of their natural habitats. TheDirective makes explicit mention of wide-ranging and dispersal species, particularly aquaticspecies, for which site-based conservation measures are of limited value. Features of the


wider landscape, and indeed the marine environment, are clearly significant for thesespecies. Corridors encompass the particular landscape features and contribute to theoverall character of an area capable of supporting such species at favourable conservationstatus. The following functions are related to the conservation measures required to achievefavourable conservation status:1. Ensuring adequate breeding success for viability of populations,2. Allowing expansion of existing populations in their natural habitats,3. Allowing expansion of populations into areas within their natural range currently not

occupied ,4. To meet the migration and seasonal movement needs of a species,5. Allowing populations across their natural range to be ecologicaly integrated.

Within this framework, ecological corridors should be defined hierarchically and at leastat two administrative levels, Pan-European and national/regional. However, from aconservation planning point of view, corridors should be designed at three ecologicallymeaningful levels: a supra-regional level, a regional level and a local level. Paneuropean (orsupra-regional) corridors should(a) mainly provide migration routes for species at the European level, either in a seasonal

perspective or in view of longer term forced movements related to global changes, and(b) should allow geographic expansion of species. Regional corridors should mainly

provide access to rescue areas (temporary survival areas for species leaving theirshelter areas and habitats) and support wide ranging animals.

Abiotic processes such as nutrient transfer or water cycles are also defined at this level.Local corridors should support the biotic and abiotic spatial processes, flows andmovements which are defined at a landscape level (sensu Forman and Godron, 1983).

1.5.5 Implementation

European and national or regional ecological networks are based on policy objectives, andapproaches are derived from these objectives. Nature conservation objectives are based onecological principles, but can be interpreted differently because of differences in ecologicalconcepts that play a role in the national or regional policy. They vary from the conservationof species to the conservation of natural and cultural landscapes. Due to a difference innature conservation history national strategies show great differences in Europe, but thepolicy objectives are more or less comparable: the protection of areas of high natural valuesin designated areas. However, differences in policy are expressed in the way natureconservation is implemented. Countries with strong planning traditions do approachnature conservation problems in a different way than those countries that lack planningtraditions. Objectives may be comparable, the methodology that is used and the functionof the planning can differ strongly.

In many countries nature conservation has a long development. It has become a field ofpolicy and is gaining force especially in the last decade. Knowledge and ideas fromlandscape ecological research found their way into nature conservation policy strategies.The development of coherent spatial structures is the most obvious part of it and ecologicalnetworks became an important strategy in nature conservation in The Netherlands,


Flanders and Germany. In the Central and East European countries integrated planninghas a strong tradition. Nature conservation as a independent policy had a minor position,but it developed in the framework of physical planning and other forms of integrativeplanning. In this framework elaborated ecological networks have been developed consistingof several hierarchic levels. Most of the networks are part of a systematic approach and arein a process of realization. The present situation of renewal and change in policy systemsoffers both opportunities and threats because of the changes in the system of ownership.This causes a great amount of uncertainty.

National and regional networks have comparable structures. They consist of core areas,corridor zones and buffer zones and have a basis in metapopulation theory and islandbiogeography theory. The networks are hierarchical structures on national to local levelexcept for the Danish "Regionplan", that only functions at the regional level. Differencesin planning systems and national or regional priorities make it difficult to relate thenational and regional planning systems for nature. A first attempt to relate nationalstrategies systematically has been discussed at the conference on European coastalconservation (Udo de Haas and Vertegaal, 1991).Two regional European studies have nowbeen carried out, by the IUCN for the Central European countries (Czech Republic,Slovakia, Hungary and Poland and one for the Benelux (Jongman and Van de Windt,1995). In many countries in southern, central and eastern Europe nature conservationstrategy is now in a pioneer phase. The planning system and the legislation for natureconservation and related land uses is in development. Natura 2000 can be at one hand theincentive for governments to develop a nature conservation policy, on the other handnational policies can enforce the European network by developing spatial coherence. It isthis process of mutual enforcement that has to be started and that possibly will lead to acoherent ecological network for all Europe.

Regarding the guidelines for buffer zones and corridors the following steps describe anorderly suite of phases in relation to the Habitats Directive prescriptions:

1. Favourable conservation status needs to be defined as the starting point. That can bedifferent for all NATURA 200 sites, because most will be a complex of habitat types ofdifferent sizes and with different characteristics and species composition. The objectivemust be clear that it is possible to derive guidelines for the management of:Ø species:(1) habitat quality, (2) habitat size and (3) possibilities for exchangeØ abiotic features from the wider environment, (1) vital inputs and (2) pollution from

water, and air orØ human impact through land use and traffic systems.

2. The contribution of protected areas to favourable conservation status of species andhabitats needs to be established and the conservation objectives of each site must beanalysed in the light of this. This is comparable to an analysis of strengths, weaknesses,opportunities and threats.

3. Optimization of the conservation status might need action by enforcing strengths andopportunities, diminishing threats and preventing development of weaknesses.Strengths and opportunities are the positive aspects of a conservation area. These can be


linked to the objective of the Natura 2000 site but also to its location. The strength of a sitecan be its very vital population, and the opportunity can be that there are possibilities toenforce the functioning of the site for the wider countryside because there are many emptyniches or a good network of corridors for dispersal exist.

Weaknesses can be both internal and external. An internal weakness can be the shape ofthe core area or the small size of the key populations in it. An external weakness can be thedistance between the core area and forgaging areas outside for migrating species.Threats are always external but can be introduced into the core area, like recreationfacilities near a vulnerable site or population. External threats can be abiotic e.g. pollutedwater, or anthropogenic, e.g. land use.

4. Other measures to meet the ecological requirements of each habitat and species toachieve favourable conservation status will include specific contributions from outsideprotected areas, and these can be described in terms of landscape character and features.This can be as buffer zones including particular buffering systems as "managed retreat"for flood defense, particular uses for set-aside land, and so on. Corridors and steppingstones should be defined as the features and characteristics of the main land uses in thearea contributing to the conservation status of the species an area supports or shouldsupport.

5. Wider threats to the conservation status of wild species and natural habitats will beidentified. These are likely to be best addressed by wider policy measures reducing thechallenges to the environment or to the species concerned. These are administrativemeasures controlling the activities and methods used by organisations and individualswhere these affect the conservation status of habitats and species.

Coordination or integration of the local, regional, national and international level is animportant aspect for policy making. The integrated planning systems seem to have anadvantage in this matter. However, the short nature conservation history, the complexityof integrated planning and the political changes in most of the central European countriesmay hamper the success of this planning system. The Dutch system seems to be complex aswell, but it appears to function and even larger projects are getting started. The Danishapproach, a strongly decentralized policy, shows to be very successful to realize smallerprojects, but also here larger projects are initiated and co-ordinated at the national level.

There are differences in ecological network systems depending on land use history andpresent agricultural policy. Economic conditions as overproduction in most basic foodproducts and free market rules are driving forces for land use changes. The commonagricultural policy (CAP) of the European Union but also the official environmental policyof the Ministry of Environment and the Ministry of Agriculture of the Czech republic arenow beginning to be directed on the reduction of subsidies on agricultural production andslowly to support landscape multifunctionality and to keep traditional settlements in therural landscape. It is estimated that in the Czech Republic about 15 percent of the totalagricultural land will be available for set-aside programmes. Regional differences in landuse development depending on natural conditions, especially on soil fertility and landsuitability for agricultural production will be emphasized in this way.


Directing this change in land use also according to nature conservation objectives mighthelp to develop supporting systems for nature conservation areas and especially for Natura2000 sites. Nature conservation objectives can be used as a guiding principle for land usesupport to farmers in sensitive areas. That allows farmers to get an income and preventsland abandonment.

In intensive farming areas the preconditions for nature conservation could havefar-reaching consequences for the management of the agriculture. Van den Aarsen (1994)showed that in the Netherlands the implementation of ecological networks means areduction in acreage, the necessity to reduce the release of nitrogenous compounds andphosphate, the use of groundwater and the requirement of space for the creation ofstepping stones and corridors.

The means for implementing ecological networks are limited. There exist the possibility tostimulate extensification of agricultural land use through the policy of EnvironmentallySensitive Areas (ESA). However, the number of ESA schemes that can be supported byCAP is still restricted. Structural support for buffer zones and landscapes with a corridorfunction could help greatly to reach the favourable conservation status.That means that thefuture scenario given by the proposed ecological networks gives a nice outlook towards abetter future, but that the road to get there is still under construction.


2. Spatial strategies for nature conservation.

2.1 Introduction

It is generally accepted that nature conservation strategies based on the designation ofparticular sites rather than on the whole territory have not been successful, at least in termsof conservation of biodiversity (e.g. Shafer, 1991) As habitats within a landscape areinterconnected, the conditions within designated areas are influenced in many ways byhuman activities in the surrounding land. Examples are acid deposition, lowering of watertables, deterioration of foraging and resting areas for animals, disturbance of migratingorganisms, inflow of waste water and disturbance by recreation. A designated area strategymay often prove insufficient by itself in maintaining and upgrading biodiversity withindesignated areas because ecological processes and external influences defined and/orpromoted on larger scales, through the interconnection of habitats, are not taken intoconsideration for the management of the area (site). These influences on designated areasby human activities in their surroundings have resulted in the need for a spatial strategyin nature conservation (Farjon and Bakker, 1995).

Furthermore, habitat and landscape fragmentation affects negatively ecological andpopulation processes. In landscapes in which natural areas are being increasinglyfragmented, maintenance or restoration of habitat connectivity has become a central goalof biological conservation (Noss, 1993). The classic approach in nature conservation, thatis the conservation of target species and other valuable nature features within strictlydelineated protected territories, is currently re-oriented towards the differentiated care ofthe whole landscape (Miklos et al., 1995))

Two ideas emerge as crucial points in this context. The first is that the limitation, controlor regulation of certain human activities in areas outside designated sites is essential infacilitating biodiversity within a reserve. The second is that there is a hierarchy inconservation objectives generating nested protection levels, necessary for the maintenanceof the stability of the landscape. The major pre-condition for the ecological stability of thelandscape is the maintenance of the spatial relations between ecosystems (of various levelsof stability) through a spatial system of functionally interconnected elements, i.e. anecological network.

An ecological network is composed of core areas, (usually protected by) buffer zones and(connected through) ecological corridors (Bennett, 1991). Ecological corridors and bufferzones have already a history of scientific investigation and application and are becomingkey elements of the 'ecological network' strategy. As an example, regarding speciesconservation at a population biology level, the ecological network should ensure three maintypes of ecological processes at a landscape level:1. vectorial processes associated with environmental gradients, such as the movement ofseeds or the circulation of nutrients through rivers, slopes etc.2. equi-potential processes, allowing the dispersion of species between habitats of similarenvironmental features, and3. processes associated with border effects of ecotones.


Historically two approaches in spatial strategy can be distinguished, the landscape-approach and the habitat-approach. The landscape-approach considers not only ecologicalbut also socio-economic and aesthetic functions of corridors and buffer zones. The habitat-approach, on the other hand, simply optimizes their ecological functions (or even oneecological function). As such the habitat-approach tends towards technocratic solutionsdenying a socio-economic context of the problem. Traditionally the landscape-approach isbased on landscape patterns instead of landscape fluxes. To overcome the problems anddifficulties of these approaches there is a need for the definition of a land system-approachin the allocation and management of corridors and buffer zones. This approach shouldincorporate the best ecological knowledge on landscape fluxes of the habitat-approach withthe awareness of social-economic and aesthetic functions of corridors and buffer zones ofthe landscape-approach.

Ecological networks are more widespread in Europe than many would suppose (Jongman,1995). Reviewing recent developments concerning ecological networks, Arts et al. (1995)concluded that "during the last decade, the nature conservation policies in many Europeancountries have been based on landscape-ecological research, especially concerning the roleof land use and landscape structure in the survival of species and in the protection ofnature reserves. Plan proposals were made to establish ecological networks on local,regional and national scales." However, because the land-pattern design is the dominantapproach, landscape linkage elements, especially ecological corridors, are integral parts ofconservation plans in theory more than in practice in Europe. Certainly, differences areobvious between countries. Scientific, political and social tradition and history areimportant in understanding these differences.

2.2 Nature conservation and physical planning in The Netherlands

In the Dutch Nature Policy Plan (Ministry of Agriculture, Nature Conservation andFisheries, 1990) it is stated that optimal habitat conditions within protected areas need anetwork of habitats large enough to sustain viable populations, connected by ecologicalcorridors and protected from external influences of acidification, eutrophication anddesiccation. The design of the National Ecological Network (NEN) includes indications forexpansion of core areas (nature development areas) and ecological corridors. Locations forbuffer zones, however, are lacking. This will be developed as a special policy, because oflocal and regional differentation that can be of importance.

In order to develop a national buffer policy for NEN's core areas, Geesink and Bleuten(1992) executed a national survey of hydrological and atmospheric buffer zones. Thissurvey indicated that hydrological buffer zones for the Ecological Main Structure requiredan area of more than 6,000 km2. According to this survey the size of atmospheric bufferzones is too large for implementation in physical planning.

By Farjon and Bakker (1995) land outside designated areas with a common purpose forfacilitating biodiversity within designated areas are called nature facility areas (NAFA's).NAFA's areas are defined as those areas which are not designated as nature reserves butwhich have certain limitations to human interference in natural processes in order to


facilitate abiotic, biogeographic and social-economic conditions for biodiversity withindesignated areas. Buffer zones and ecological corridors are generally accepted terms forNAFA's. According to these authors, the spatial strategy in nature conservation focuses onallocation and management of the so-called NAFA's.

NAFA's can be characterized/typified by: - the conditions that are facilitated by landscape fluxes, - the function of these landscape fluxes for these conditions;

The occurrence of wildlife species within a certain habitat is, amongst others, determinedby the optimal availability of water, nutrients, energy, organisms and human disturbance (five habitat conditions). Within a habitat-network the optimal habitat-condition is relatedto a certain steady state of landscape fluxes, such as air movements, water flows, migrationand human transport. Within the perspective of landscape fluxes sub-optimal habitatconditions in a designated area can result from too small or too large in- and outputs ofwater, matter, energy, organisms and/or man. For instance, manuring upstream of aswamp leads to a larger input of matter into this swamp-habitat and subsequently to itseutrophication.

By changing human influence in other parts of the ecosystem network habitat-conditionsin the designated area may regain their former optimal status. Four network controlprinciples can be distinguished in optimizing fluxes for a certain habitat (Figure 1):

- limiting inputs: buffer control principle - increasing inputs: supply control principle - limiting outputs: retention control principle - increasing outputs: extraction control principle

Figure 1. Ecosystem network control principles (Farjon and Bakker, 1995)


A typology of NAFA's is generated by combining these four network strategies with the fivehabitat-conditions. However not all combinations are relevant in nature conservation. Forinstance too few nutrients is seldom a problem in nature conservation. Table 1 summarizesrelevant NAFA-types and gives their commonly used synonyms. For clarification purposessome measures with a limited spatial extension are also given.

Water supply areas are areas outside designated areas with such allocation, design andlimitations to land use that an optimal supply of water to water-dependent habitats withindesignated areas is guaranteed. Examples are watershed management strategies (forinstance terracing and reservoirs) to guarantee water supply in brooks, rivers andfloodplains during dry periods. The water management plan for the Dutch provinceGelderland indicates restrictions to groundwater extraction and forestry in somegroundwater infiltration areas in order to guarantee groundwater supply to seepage areaswith calcareous fens and bog woodlands.

Water retention areas are areas outside designated areas with such allocation, design andlimitations to land use that an optimal retention of water in water-dependent habitatswithin designated areas is guaranteed. Examples are water-retention strips around bogs,mires and fens, bog woodlands and wet heaths. In Northwestern Europe water-retentionpilot studies are known from bogs in North Germany, England, Scotland, Ireland and theNetherlands.

Table 1 : A functional typology of Nature Facility Areas (Farjon and Bakker, 1995).

Habitat-condition Supply Buffer Retention Extraction

water :- too dry or desiccation

watershedmanagement,infiltration areamanagement,reservoir

water conservation strip, weir

water :- too wet or flooded

watershedmanagement,flood-control dam

spillway

nutrient :- too rich or eutrophication

watershed management, buffer strips, dam

no spatialsolution

energy :- too hot

no spatial solution too hot : greenbelts

organisms : corridors, stepping no spatial solution


- too few or extinction stones

organisms :- too many orcompetition

no spatial solution no spatial solution

man :- too much or disturbance

buffer strips, fences recreation facilities

Water buffer areas are areas outside designated areas with such allocation, design andlimitations to land use that an optimal buffering of floods in habitats within designatedareas is guaranteed. An example is watershed management strategies such as terracing inorder to prevent peak flows that can be disastrous to floodplain ecosystems.

Water extraction areas are non-designated areas with such allocation, design andlimitations to land use that an optimal drainage of water from habitats within designatedareas is guaranteed. An example is the construction of spillways in order to prevent extremeflooding of floodplain ecosystems.

Nutrient buffer areas are non-designated areas with such allocation, design and limitationsto land use that an optimal nutrient status of air and water flowing to habitats withindesignated areas is guaranteed. In Northwestern Europe many studies focus on the designand efficiency of buffer strips and artificial wetlands to reduce nitrogen concentration inbrooks, rivers, overland flow and groundwater that influence a wide range of ecosystems(Haycock, Pinay & Walker, 1993; Jansson et al., 1994; Knauer & Mander, 1989; Duel,During & Kwakernaak, 1993).

Energy extraction areas are non-designated areas with such allocation, design andlimitations to land use that an optimal discharge of energy from habitats within designatedareas is guaranteed. As far as known this control principle is not applied in natureconservation. The construction of green belts penetrating large urban areas in order toobstruct an urban heat island is a fine example of ecology-based urban planning(Landsberg, 1987).

Organisms supply areas are non-designated areas with such allocation and design that anoptimal migration between habitats within designated areas is guaranteed. Examples areecological corridors and stepping stones that allow animals to migrate through ratherhostile areas. Migration can serve different functions for organisms such as dispersal ofyoungsters, seasonal or daily migration from/to resting foraging areas.

Human disturbance buffer areas and men-extraction areas are non-designated areas withsuch allocation and design that human disturbance of habitats within designated areas islimited to an ecologically sound level. Both physical defence to intrusion (buffers) androuting of recreation by diverting into other attractive recreation facilities (extraction) arewell known control principles.


2.3 Nature conservation and landscape ecology in Slovakia.

The Territorial System of Ecological Stability (TSES) in Slovakia is a relevant example ofthe hierarchization of conservation objectives and of the consequent planning approaches.Miklos et al. (1995) report that TSES might be defined as "a whole space covering systemof an ecologically optimum structure of the landscape, composed by individual elementswith different degree of ecological stability and of different use, but as a whole ensuringboth (a) the internal functioning of the individual core ecosystems, and (b) the functioningof the spatial relations among them, as a precondition for the maintenance of the diversityof both the conditions and forms of life and thus the spatial landscape-ecological stability".The very recent Nature Protection Act in Slovakia (1994) proposes TSES as the main toolfor the maintenance of the stability of the landscape. According to Miklos et al. (op.cit.)"man needs different ecosystems and landscapes. Different landscapes may be loaded bydifferent activities of humans, but at the same time differently loaded ecosystems (includingheavily burdened ones) might function also as biocenters for certain species, populationsand communities (which are also parts of the diversity of the life, in spite they areinfluenced or even conditioned by man). The objective of sustainable development and ofnature conservation is to maintain the whole range of the diversity of the landscapes, i.e.the whole territory on a different hierarchical levels. So, in fact a territory might beconsidered at the same time as a core area on certain level of ecological stage and legalprotection, and on the other hand as a buffer zone for a core area with higher level ofprotection".

In practice, according to that Nature Protection Act, the whole territory of the SlovakRepublic is protected at 5 different levels (with increasing protection from level 1 to level5). This is the core principle of the differentiated care of the whole territory. Figure 2shows a schematic presentation of the principle of nested protection levels. Natureconservation and physical planning are closely related and are carried out in differenthierarchical levels (Miklos 1992, Doms et al, 1995).

Figure 2: Hierarchisation of nature conservation objectives: the case of Slovakia (Miklos etal, 1995).


Legend:1st level: the whole territory of Slovakia2nd level: Protected Landscape Regions (PLR), but also protective belts of national parks(NP), parts of biocorridors of TSES3rd level: NP, but also protective belts of Protected Areas (PA), zones C of NP and PLR andparts of biocorridors of TSES4th level: PA, but also protective belts of Nature Reserves (NR), nature monuments (NM),zone B of NP and PLR, biocentres, parts of biocorridors, interactive elements of TSES5th level: NR, NM, but alsozone A of NP, supraregional biocentres of TSES

2.4 Nature conservation and land use in Madrid Region, Spain

Nature conservation in Spain has a long tradition. The act on national parks origuinatesfrom 1916 and the first national park has been founded in 1918 (Covadonga). Now natureconservation is regionalised. That means that the main responsibility is at the regional level.Although road construction, housing, modification of groundwater flows and modernagriculture reduce the range of natural and semi-natural habitats and increase theirisolation, fragmentation is less evident in comparison with Northern European regions.Large parts of the landscape maintain their high natural values. Functional connectivitydoes not depend necessarily on distinct linear landscape elements (corridors), but thelandscape matrix itself may serve as a "corridor". Even though conservation policies arestill site-based rather than area-based in Spain, spatial strategies are gaining momentumemphasizing the need for new approaches aiming at the conservation of the whole territory.

The most striking element of land use change in the Madrid region during the last 40 yearsis the progressive abandonment of traditional activities leading to the decline of wetpastures, riparian forests, etc. Any conservation strategy in Spain, and in Madrid regionin particular, must take into account the important role of traditional land uses. A 'dehesa'supports a highly diverse system of production by combining grazing, farming and forestry,and permits the coexistence of natural elements together with agricultural elements (Pinedaet al ., 1991). The abandonment of traditional practices causes biological simplification,raising the risk of big fires or leading to the loss of valuable elements which structure thelandscape such as stone fences, hedges or ponds (Ruiz, 1989). The conservation oflandscapes, guaranteeing the preservation of certain ecosystem functions and values suchas erosion control, rainwater infiltration, stability of snow deposits, resistance to fire,biological diversity, and so on, depends on the maintenance of traditional uses, even if themethods are to be modernized (Bernáldez, 1988).

In this context, preservation of sites is clearly insufficient. A first proposal for the designof an ecological network in Madrid region is currently under development, focuses, amongother important objectives, on the need for the identification of the elements of the network(CIFGB, 1995). Till now, criteria such as representativeness and biological and landscapediversity have been poorly taken into account in the design of the nature protection system. Hence, important parts of the territory have not yet received the proper legal recognition:riverine systems, mountain ranges, dehesas or structures related to traditional land uses,


such as drovers' roads, need to be recognized as vital elements of the network whichprovide connectivity and buffer the actual or potential protected areas. The identificationof the functions and structure of corridors must be directly related to the features of thelandscape matrix.

2.5 The nature conservation directives of the European Union

The Habitats Directive (43/92/EU) and the Birds Directive (409/79/EEC) establish similaroverall objectives, namely the conservation of naturally occurring wildlife and its habitatsin the European Territories of the Member States. Both also identify priority features,habitats and species, based on the danger of extinction, vulnerability, population size orabundance, restricted distribution or specific requirements. The relevant prioritycomponents are listed in Annexes to the Directives.Both Directives set out measures to achieve these objectives, giving particular weight tothose needed to achieve the goal for priority elements. This is described as "favourableconservation status" in the Habitats Directive, and as "the population level whichcorresponds to ecological, scientific and cultural requirements" in the Birds Directive. Inboth, the concept of distribution is an important part of the objective, at least for thepriority elements.

The measures proposed include the identification of a coherent network of sites which issufficient to meet the protection needs of the target species and habitats, given the needsto achieve the conservation goal. Additional measures are also supported, including thecreation and restoration of further habitat outside protected areas, the promotion ofhabitat management, and a system to protect the habitats, sites and individual species fromadverse effects.

In the directives the terminology is dufferent. In this report it is taken that "populationlevels that correspond to ecological and scientific requirements" and "to ensure their survivaland reproduction in their area of distribution" is equivalent to favourable conservation status.The components of favourable conservation status need to be set out for all the prioritybird species and the habitats and species of Community interest. Once this is done themeasures required to secure this status and the contribution made by protected areas toenable this can be defined. The specific objectives for each selected site can then be set outin detail and measures can be derived from that.

Each site selected under the Directives will have specific conservation objectives. These aretaken as achieving the conditions required so the site contributes to Natura 2000 as plannedand as achieving the planned contribution to favourable conservation status of the priorityelements for which it was notified. The requirements to achieve the conservation objectivesfor each site can then be determined. Buffer areas are one way of meeting the requirements set out in Article 6 of the Habitats and Species Directive. Paragraphs 2, 3 and 4 apply toBirds Directive sites. Article 3 (2) (b) of the Birds Directive requires the upkeep andmanagement of habitats in protected areas, and is the equivalent of Article 6 (1) of theHabitats Directive.


Article 10 of the Habitats Directive refers to the landscapes which are of major importanceto wild species. Features that are essential for dispersal, migration and genetic exchangeare highlighted. The idea of ecological coherence of the suite of sites making up Natura2000 is given particular emphasis.

The Birds Directive also refers to the idea of a suite of sites as a coherent whole, given theprotection needs of the species concerned. Both Directives include the idea of ensuring thatthere is sufficient area and diversity of habitat to meet the conservation needs of the targetspecies. This explicitly includes habitat creation as well as re-establishment andrehabilitation of species in the Birds Directive. This is implicit in the Habitats Directive inthe definition of favourable conservation status which mentions "sufficient area of habitat"to maintain the population of the target species in the long term.

The contribution of ecological corridors and buffer zones to favourable conservation statusneeds planning as part of the overall set of measures needed to achieve the above objective.Ecological corridors and buffer zones are areas that have a specific contribution to theconservation needs of named species for which favourable conservation status has beendefined.3 Buffer zones.

3.1 Definitions.

The concept of buffer zones is rather old (Wright and Thompson, 1935). Literature offersa number of definitions, related to the approach used for their design within the frameworkof spatial planning and management.Within a hardly anthropocentic view of nature,Jehoram (1993) distinguishes the nature management-approach and the landscape-approach generating different definitions, allocation criteria and management strategiesfor buffer zones. The nature management approach can be illustrated by the IUCNdefinition of a bufferzone: a zone peripherical to a national park/reserve where restrictionsare placed upon resource use or special development measures are undertaken to enhancethe conservation value of the area (Oldfield, 1988). The landscape approach is expressed inthe World Bank definition: a social agreement or contract between the protected area andthe surrounding community, where size, position and type of bufferzone is defined by theconditions of this agreement.

Within the framework of an ecological network strategy, as is the case for Natura 2000, thedefinition of a buffer zone should integrate both lanscape and functional attributes. Adefinition based on the ecological function(s) of the buffer zone should focus on its mainmanagement objective (Miklos et al., 1995)a. protection, to protect from the expansion of harmful man activities,b. interaction, to sustain positive landscape interactions,c. diffusion, to sustain natural and man-made flows in the landscape.Partial definitions of buffer zones based on the ecological function(s) they fulfill areproposed by Farjon and Bakker (1995).

Landscape alteration outside the boundaries of a core area generally causes important


biotic changes within it. By creating environmental gradients buffer zones intend tomaintain landscape processes and elements around the natural remnant to avoid abruptchanges. Common sense and the slowly accumulating practical experience allow us torecognise that the fundamental role of protected areas would not be achieved if the primaryneed of controlling adjacent human activities that influence them is not accomplished.Buffer zones may be viewed as a shield around the core area against the direct impact ofhuman activities. Human activities should be viewed both macroscopically as more or lesschanging land use, and at their physical dimension as disturbances generating a long seriesof abiotic and biotic fluctuations influencing species and communities under protection.

The ideal form of a buffer zone is materialized in the "ring pattern" of UNESCO'sBiosphere Reserves (UNESCO, 1974). According to a concentric zoning design, at least, twokinds of rings are defined: the inner ring, the core area, contains the biologically mostimportant areas. The next ring or set of rings is a buffer zone where plans of controlledresource management are applied, and where traditional cultural activities are permittede.g. in the outer ring agriculture can be the main land use.

The participants in the CIFGB workshop stated that although national parks and otherconservation areas are meant to conserve species and habitats, they usually are not withoutimpact of the land use around it or upstream. They concluded that the following definitionof a buffer zone is appropriate:

Buffer zones are areas where the management objectives are aiming at the regulation offluctuations of abiotic, biotic and man-related factors in the land adjacent to a naturalremnant (entire -or parts of- NATURA 2000 sites), designated as a protected area.

3.2 Multifunctionality of buffer zones

The buffer zones are intended to serve direct ecological purposes related to theminimisation of the effects of landscape fragmentation and core area diminishment andisolation. Buffer zones aim at controlling human activities within the lands adjacent to acore area by promoting sound management, thus decreasing the potential impacts anddiminshing effects of small size. The presence of indigenous people is implicitely permittedwithin the buffer zones, otherwise the buffer zones would be a totally protected area. Whatdegree of human intervention or activity is then tolerated within a buffer zone? Experiencesuggests that the success or failure of buffer zones is correlated with the efficiency andability of reserve planning and zoning in estimating the carrying capacities of the differentzones (core areas + buffer zones). The current approach in buffer zone design tends toaccept them as areas where a plan of land-use regulations is applied rather than as clearlydefined areas that could have legal protection.

To develop a buffer zone means an analysis of the objectives of the core area. A statementof positive needs and specific threats to the conservation objectives should be prepared foreach site. It is important to keep the elements within these statements on an appropriatescale. General air pollution, for example, is likely to be a factor identified at the level offactors affecting the capacity to achieve favourable conservation status rather than one that


affects individual sites independently. It needs to be managed on a national andinternational scale. However, local air pollution from particular types of development, suchas intensive livestock units, is likely to be best considered at a site by site level. Once astatement is prepared, the measures to address the needs and specific threats can bedetermined. In some cases buffer areas of one sort or another will be appropriate. A bufferarea addresses a specific need for a particular site with particular conservation objectives. Buffer areas may address a number of specific needs. Each buffer area may alsocontribute to other needs. The best practice should encourage the management of bufferareas such that they do contribute to other purposes as far as it feasible given their primaryfunction. The following major management functions for buffer zones can be enumerated:

1. Accomplishment of area requirementsInsufficient area of protected sites for the long-term survival of some species is common tomany national parks and reserves. This probably will be the case with many Natura 2000sites due to their small size and the insular approach of the designation criteria. In thesecases, buffer zone should provide space for wide-ranging species, such as large carnivoreswith large home ranges, geese requiring foraging sites nearby moulting sites and for rarespecies for which the core may be too small to permit an adequate population size. Thus,buffer zones are viewed as opportunities and capital for the needs of future management andexpansion of the size of core areas.

2. Correcting the shape of the core areaThe shape of the core area is crucial for the accomplishment of several key functions. Anecologically optimum patch shape usually has a large core with some curvilinear boundariesand narrow lobes, and depends on the orientation angle in relation to surrounding flows(Forman, 1995). In that case, buffer zones may play the role of correcting the shape of thecore area, in order to:-minimize the exposed perimeter to outside effects and conserve internal resources moreefficiently,-facilitate interactions with adjacent ecosystems and with more distant portions of thelandscape (the optimum shape may differ in respect to the interaction process),-correct the orientation of the long axis of the core relative to flows (e.g. wind, water,nutrients, individuals) in the landscape.

Figure 3. The National Park of Mercantour. Zone A represents the core area, zone B thebuffer zone.


This feature of a buffer zone becomes more and more important as the size of the core areadecreases. In the case of many small-sized Natura 2000 sites, buffer zones should serve asmanagement tools to integrate them efficiently in the landscape functional flows. Forexample the Parc National de Mercantour has a long axis of about 75 kilometers and awidth of locally less then two kilometers connecting a series of mountain areas. The bufferzone is essential in completing the national park (Figure 3).

3. Support of direct site managementWhilst the boundary of protected areas will correspond to the particular interest for whichthe site is identified, the practical management system required on the site may requireadditional areas to allow sufficient control. Grazing within protected areas often requiresdifferent numbers at different times of year, and may require short term adjustment ofnumbers in response to the needs of the interests on the site. To achieve this additionalland may be required to hold stock. Where this cannot be integrated into the wideractivities of the managers of the site, land will need to be identified for this.

4. External management purposesThe requirements include the management of factors that directly affect the ecologicalconditions on the site. These may also affect the response of the habitats and species withina site to management on the site. For example, water levels within a protected area maybe managed on a scale larger than the site, and will affect the ecological results of grazingand cutting management on the site. To address this situation a buffer area may berequired that covers the management scale that is relevant for the factor concerned. Thisshould be restricted to factors that are directly managed, such as water levels and drainage.


5. Immediate protection purposesThe direct primary effect of fragmentation is related to changes in microclimate within andimmediately surrounding natural remnants. These changes provoke alterations to theenvironmental conditions of the habitat (Saunders et al., 1991). A mega-edge effect is thencreated, the consequences of which for biological diversity are still poorly understood.These physical changes together with changes in the nature of interactions between speciesgenerated by isolation probably transform the nature of the core habitat under protection.Changes and their consequences are certainly different for different species and differentkinds of habitat. In that case, buffer zones appear as a sensible strategy to seal off coreareas from further microclimatic changes.

Also the management of land adjacent to protected areas affects the protected areas. Spray drift and nutrient enrichment are examples. This may require adjustments of theseactivities on adjacent land. When identifying areas from which significant impacts deriveas buffer areas, the activities within the latter should be modified sufficiently to remove anythreat. This can include areas that stem the impact by capturing or filtering the adversematerial.

6. Protecting traditional land use and deflecting threatsAccording to recent versions of the ideal Biosphere Reserve model, indigenous people andtheir long established patterns of land use were not incompatible with the concept. Beyondthe "varied or harmonious landscapes", i.e., landscapes created by past pastoral oragricultural activities, it is accepted that even "modified or degraded landscapes" may beincluded within a peripheral buffer zone system. Furthermore, the newest concept of"multiple use zone", which can in some cases accommodate cattle grazing, farming,forestry, settlements, etc., considered as an "area of cooperation", is proposed (Peine, 1985)and often applied (in the EU, NP Abruzzo, Italy, NP Cevennes, France, or MNPV.Sporades, Greece).

Certain developments such as outdoor recreation, agriculture and housing are likely toaffect the interest within protected areas if they take place in particular locations, but areunlikely to have such direct effects if they are located elsewhere. Buffer areas can beestablished within which consultation on development proposals is required in order toensure these do not lead to such adverse effects. It is important to keep these as specific aspossible, and relevant to the nature of the threatening impacts. Partnerships with localauthorities that are responsible for development control, or for environmental quality, willoften be helped by such buffer areas. This system will help achieve the assessmentsidentified in Article 6 (3).

7. Mitigation purposesSome adverse effects can be managed by simply putting up a barrier. This really coversimmediate protection. A fence has this function where the aim is to keep people off andthus limit trampling or disturbance. However, for this to be socially acceptable, alternativeareas are often required, and where this is site specific, as opposed to a wider recreationaland access program, then a buffer area needs to be identified.

8. set aside an area for manipulative research,


Research on natural processes is important to carry out, but can mostly not be done insidethe core area. The buffer zones delivers site for manipulative research that could becompared to non manipulative research in the core area.

3.3 Buffer zones in the European experience: case studies.

3.3.1 The landscape approach: zoning system for protected areas.

This approach does not discriminate between specific functions of corridors and bufferzones. Shape, size and allocation of buffer zones are closely related to former or existinglandscape patterns, such as species distribution, land use and linear landscape features.New forms are hardly site-specific, for instance the circumcircular shape of a buffer zone.The landscape-approach resulted in a zonation of land use outside nature reserves. Zonesare defined by different degrees of limitations in human interference to natural processes.

Conservation planning in Spain, France, Italy and Greece follows common principles,though the extent of their application and implementation in practice greatly differs amongthese countries. Buffer zones are commonly used in the design of nature reserves and parks.In Slovakia, buffer zones are designed (at the appropriate level) for Biosphere Reserves,National Parks, Protected Areas and Nature Reserves.

Some elements of the designation and design process of protected areas appear to besignificant for the understanding of the implementation procedure of the Nature 2000network and the effort for diminishing size effects and the isolation of the sites (Figure 4).

1. The major common trend in conservation is the striking bias toward the selectionof mountainous areas (even of high altitude) as nature reserves, in comparison toother ecologically significant biotopes/habitats (e.g. wetlands, grasslands, riparianecosystems, marine and coastal areas).

2. The protected areas have mostly been selected with the scope of protecting precisetarget animal species. The broader ecological value of the ecosystems (biodiversity,scenery, ecological processes, etc.) is a secondary selection criterion and theirprotection is a positive "by"-product of the species oriented conservation strategy. Conservation biology has already presented an extended discussion on the benefitsof protecting large species on the conservation of smaller or restricted species.

Figure 4. Relation between the surface of core areas and the surface of buffer zones in someEuropean national parks (Examples from Italy, Greece, France and Slovakia: it should benoted that in only 1 Italian National Park -among 24- and in only 5 Greek National Park -among 10- buffer zones are reported).


3. The zoning system, when applied, is mostly oriented towards the regulation of humanpresence. Physical planning approaches for the regulation of water nutrient andorganism fluxes are not considered as components of the conservation policy domain.

However, important differences in quantitative and planning parameters (surface, bufferzone/core area ratio, shape, etc.) exist in the application process of the zoning system amongthe above mentioned countries. Figure 3 illustrates this fact: e.g. Greek national parks areconsiderably smaller than the French and Slovakian ones, or the buffer zone/core ratiovaries enormously.

3.3.1.1 The National Park of Abruzzo (Italy).

The Abruzzo National Park is situated in the middle of Italy, in the Central Apennines, nottoo far from Rome. It is an area of mountains and forests of outstanding beauty, the laststronghold for endangered species, such as the Abruzzo Brown Bear (Ursus arctosmarsicanus), with about 70-100 specimens, the Abruzzo Chamois (Rupicapra ornata), 450-500 specimens, the Apennine Wolf (Canis lupus italicus), 35-40 specimens. It has been thesite for a largely successful reintroduction of some species that had vanished in the past,such as the Red deer (Cervus elaphus hippelaphus), now counting 500-600 individuals, andRoe deer (Capreolus capreolus), with a population of 150-200 still increasing. There areabout 40 species of Mammals, 300 of Birds and 30 of Reptiles and Amphibians in the Park,as well as a very rich and distinctive flora, including more than 1200 species of higherplants with many endemic and rare taxa (Tassi, 1984) .


The actual size of the Park is 44.000 hectares, surrounded by an Exterior Protected Areaof about 60.000 hectares, covering parts of the territory of 3 regions - Abruzzo, Latium andMolise - in a master plan of conservation and management (figure 5).

In order to better achieve its institutional purposes, the Abruzzo National Park was thecentre of special planning efforts by means of the so-called zoning system. This consists insubdividing the territory into various zones subject to diversified protection andmanagement systems:

Zone A: Strict nature reserve deserving absolute protection (IUCN Category I);Zone B: Natural environment, supporting only very limited traditional activities

(IUCN Category II);Zone C: Countryside, ffor the protection of cultural landscapes (IUCN CategoryV);

and,Zone D: Villages and other inhabited areas promoting development reconcilable with

park aims (IUCN Category VIII).

More precisely, in Zone A exploitation and productive use are abolished. The visitor canwalk into it discretely, and must never leave the special beaten tracks. Zone B is a vast"green space" of forests and grasslands. It was already "humanised" by millennia ofhistory, but is still substantially unspoilt, genuine and free of serious alterations or signs ofinbalance. Activities of the past can continue with sufficient care and under control. ZoneC is the classical "countryside". Agriculture and pastoral life can continue here. Zone Dis the "inhabited" space. Here the old historical centres are restored, and enriched withcultural attractions in order to develop the life of local communities in close harmony andcoexistence with the presence of visitors. It is divided into three different subzones.

Figure 5. The zoning system of the National Park of Abruzzo, Italy.


I. Subzone D1 - Inhabited CentresThese areas includes the villages which already existed inside the Park. They can developand expand according to standards and limits established by the Park's Authority andLocal Authorities.

II. Subzone D2 - Reception FacilitiesPre-existing little buildings or houses and restricted Camping grounds in the Park. Theseplaces play a fundamental role in concentration, organization and control of visitors andtourists.

III. Subzone D3 - Park OrganizationPoints of access to the Park and to services connected with it such as parking sites andpicnic areas, fauna and nature observation points and Park's tourist centres.

3.3.1.2 The Regional Park of "Cuenca Alta del Manzanares", Madrid region, Spain.

This park shows a zoning system which can illustrate one of the examples of Spanishprotected areas with a similar structure to the zoning model of core area and buffer zones(Mugica et al., 1995) . The Park covers over 46,728 ha in midland and highland mountainareas dominated by mediterranean forests of evergreen oak (Quercus ilex subsp. ballota),ash groves (Fraxinus angustifolia), dehesas or forested graslands (Q. ilex subsp. ballota,F.angustifolia, Q.pyrenaica), mainly re-afforestated pine forests (Pinus pinaster, P. pinea,P. sylvestris, P. nigra, P. uncinata), Cytisus purgans and Juniperus communis subsp.nana,and grasslands of Festuca indigesta. Besides these there are small but widespread "sotos",riparian forest of Salix salvifolia, S. atrocinerea, S. triandra and Frangula alnus.


The core area of the Park is composed by a zone A1 (Integral Nature Reserve) and A2

(Educational Nature Reserve). It represents 35% of the Park. These areas are devoted tothe protection of natural resources, landscape and cultural resources. The ecosystems aresubstantially unaltered. Farming and forestry activities are allowed only under certainconditions which guarantee the compatibility with conservation purposes. In A2 areasrecreational activities such as trekking are allowed.

"Area B" or Agricultural and Farming Park (Parque Comarçal Agropecuario) correspondsto 51% of the total area. Area B includes ecosystems partially modified by traditional landuses. Extensive stock rearing is not only allowed but promoted. Three sub-zones aredefined, relating to the level of nature conservation and production land uses: B1 orProtective area (24%), B2 or Protective area (24%), and B3 or Regenerative area (3%).Area B could be considered as a buffer area in terms of complementary ecological functionand promotion of traditional land uses.

A small area, so-called T Area or "Transition area", occupies 4% of the territory and it isdevoted to protecting the Monte de El Pardo, one of the best samples of mediterraneanforests. Sports, recreational and cultural activities are allowed. The remaining 10% of thePark are P Areas or areas subject to urban planning.

The so-called Peripheral zone of Protection should be located on lands owned by the Stateor the Municipalities, not included within the current territory considered by the law of thePark. Ecological corridors are not considered explicetly neither in the master plan nor inthe law.

3.3.1.3 The Marine National Park of Vories Sporades, Greece.

The Marine Park is a designated area, containing both valuable marine and terrestrialecosystems characterized by threatened biodiversity, interesting geomorphology andsignificant cultural, archaeological and historical aspects (Troumbis and Kardakari, 1995).The Park adheres to specific legal measures with the purpose of protecting and conservingits rare habitats or endangered species, while at the same time preserving all of its otheraspects. The Marine Park is located in the Central East part of the Aegean Sea. The areaof the the Marine National Park of Vories Sporades (NMPANS) could be characterised asa typical Mediterranean island cluster. Its main habitats are :

1. The coasts (Cliffs and Rocky Shores). The main features of its morphology are the rockyand precipitous coasts which often form caves, the main type of habitat for the Monk seal (Monachus monachus). Birds such as the Eleonora's Falcon (Falco eleonorae), theAudouin's gull (Larus audouinii), the Shag (Phalacrocorax aristotelis), the Crag Martin(Hirundo rupestris), the Rock Nuthatch (Sitta neumayer) etc., nest the cliffs.

2. The islands and islets (Islets and Rock Stacks). Endemic plant species like Campanulareiseri, Linum gyaticum, Arenaria phitosiana etc. are of particular interest, along withmosses and wild flowers. This is an important wintering place for up to 80 species ofwaterfowl. Records of the Bonelli' s Eagle (Hieraetus fasciatus) also exists. The prevailing


vegetation of the islands (maquis and brushwood) favour species of the Sylviidae sp. family.Various reptiles and mammals like the Wild goat of Gioura (Capra hircus aegagrus) formalso part of the islands' fauna.

Figure 6. Zoning system of the Marine Park of Vories Sporades, Greece.

3. The Surrounding Sea. Apart from the Monk seal, many dolphins use the area, with themost common being the Common dolphin (Delphinus delphis) and the Striped dolphin(Stenella caerueloalba).The Long-finned pilot whale (Globicephala melaena) has beenrecorded. Records of around 300 fish species exist. The Poseidonia beds in the sea,particularly important for the reproduction of species and the retention and recycling ofvarious dissolved and particulate substances of the marine environment, are widespreadand preserved in excellent condition.The total area of the Park is approximately 2200 km2

and includes 7 islands and 22 rocky islands and reefs. The whole is divided into a core andtwo zones of protection (A and B). Zone A incorporates the core (the island of Piperi andthe sea surrounding it, up to a radius of 3 nautical miles) and numerous uninhabited islets.Zone A is the top priority area for the protection of the Monk Seal. Zone B includes the onlyinhabited island, Alonnisos (3000 residents), and a number of islets and rock stacks. It formsa buffer zone around Zone A (figure 6).

Table 2. Regulation of activities within the area of the National Marine Park of VoriesSporades, Greece.


Description Activities NOT ALLOWED Activities ALLOWED

ZONE A-under water activities suchas scuba-diving, fishing ,shell-fishing, sponge fishing-fishing with medium fishingvessels within a 1,5 n. mileradius of the ishore of theisland-hunting, free camping

-the entry of all floating vessels, aslong as it has obtained the relevantpermit

Core of theNMPANS

island of Piperi and a 3n.m. range marine zonearound it

-the approach of any vesselwithin 3 n. miles from thecoast-disembarkation on theisland

A permit is required for visits onscientific purposes

ScientificResearchReserve

island of Gioura and a400 metre marine zonearound it ,between 1/12- 31/8 each year, and a1 n.m. marine zonearound it between 1/9 -30/10

-the approach of vesselswithin 400 m from the coast.-disembarkation on theisland-Surpass the speed limit of10m/h within 2 n. miles fromthe coast

A permit is required for visits onscientific purposes

SeasonalProhibitionReserve

island of Psathoura,parts of the islandKyra Panagia andSkantzoura and theislets of Korakas, Praso, Skountzili,Strogylo and a 500mrange marine zonearound them.

-the approach of any vesselexcept the professional vessels of coastal fishing,within 100 meters fromrestricted parts of the IslandKyra Panagia-The passage of any vesseland the practice ofprofessional fishing forrestricted periods of the yearfor the rest of the islands

-the transport of passengers withappropriate equipped vessels on andaround the island of Psathoura andother islands which belong to ZoneA. The permitted activities areswimming, free diving, amateurphotography and filming of theterrestrial and marine Ecosystems

ZONE B islands of Alonnisos,Peristera and DioAdelfia along withsmaller rocky islets.

-under water activities suchas scuba-diving, fishing,shell-fishing, sponge fishing-fishing with middle fishingvessels within a 1,5 nauticalmile radius of the island’scoast-free camping

-amateur fishing-professional fishing underregulations-all types of marine recreationforeseen by regulations

3.3.2 Habitat-based design and ecological function(s) of buffer zones.

As the need for a spatial strategy to protect biodiversity in nature reserves became moreurgent with growing inputs in agriculture and expanding cities, the habitat-approachemerged during the 80's. This habitat-approach optimizes just ecological functions ofbuffers and corridors and applies a process-based design. The requirements for allocationand management of a buffer and a corridor originate from specific habitat conditions ofa certain nature reserve.


3.3.2.1 Water retention in Northwestern European wetlands and water fed ecosystems.

Wetlands and water fed ecosystems such as wet heaths can suffer from lowering ofwatertables in their surrounding. Even the smallest lowering of the watertable withinprotected areas can induce prominent changes in biodiversity as water chemistry canchange dramatically when the balance between precipitation and seepage water shifts. Dueto their landscape position wetlands located on plateaus and divides, for example raisedbogs, seem most vulnerable to the lowering of water tables as can be shown in a case studyof Groote Peel bog reserve (Van Walsum, 1992; Van Walsum and Joosten, 1994).Northwestern European countries have a well established tradition in research onhydrological buffering of remnants of raised bogs. There is a coordinated research on raisedbog ecology between institutes in Germany Bodentechnisches Institut Bremen, Germany(Leegmoor and Koningsmoor), Ireland (Clara- and Raheenmore), the University ofSheffield,United Kingdom (Thornmoor) and the University of Groningen, the Universityof Utrecht and DLO-Winand Staring Centre, The Netherlands (Peelvenen, FochtelooerVeen and Bargerveen).

The Groote Peel bog reserve (1360 ha) is a remnant of the Peel bogs that extended over anarea of 3000 ha in the southeast of the Netherlands. Most of the former bog have beexcavated for fuel. The Groote Peel reserve contains a great variety of habitats, includingmarshes and heathlands, stretches of purple moor grass (Molinia caerulea), and bogwoodland. It has also a considerable extent of open water. Bog communities and plants areconfined to former peat pits where a local regeneration of bog growth has taken place. Thereserve also contains a substantial area of moist heathlands. It is among the richest birdhabitats of Western Europe, both for breeding (about 200 species), moulting, and resting(Crane Grus grus; Bean Goose Anser fabalis). The reserve was established in 1953 and hasgradually expanded to its present size. Continuous efforts have been made to raise the waterlevel inside the bog. In 1980 the area was officially designated an internationally importantwetland site by the Dutch government according to the Ramsar convention. The reserve isintended to become a National Park and in 1986 the reserve was designated a "specialprotection area" under the EC Birds Directive.

Reacting against these developments, the farmers in the surrounding land began to installsubsurface drainage. As a result, about 38% of the wetter soils surrounding the bog reservehave actually been drained since 1985. In 1989 the Dutch Government, due to a juridicalorder based on the Nature Conservation Law, designated a buffer zone, forbidding furtherhydrologic interventions within 600 meters from the reserve. This zone was subsequentlyextended to 2000 meters after another juridical order in 1990 (Figure 7).

Figure 7. Buffer zone of nature reserve "De Groote Peel"


Currently negotiations are taking place about supplying water from the river Meuse to theagricultural area surrounding the Groote Peel, intended for infiltration in the ditches thatnormally fall dry during the summer period.

With respect to the conservation objectives of bogs, the target species are bog mosses of thegenus Sphagnum. These mosses are highly sensitive to both the quality and quantity ofwater. They require ombrotrophic habitat conditions where only precipitation water feedsthe substrate. The water table should roughly remain within 20 cm under the soil surface.These habitat requirements can only be fulfilled if the following conditions are met: - The drainage base must be shallow. This means that surface water flow should stagnate; - The storage capacity within the bog must be very high; - The groundwater seepage must be directed downward and must not exceed a certainlimit.

In the actual situation all these conditions are critical. The dense artificial drainage networkfor peat reclamation has increased the surface water flow enormously. Nowadays most ofthis artificial drainage network within the reserve is dammed. The artificial drainage,however, has desiccated, oxydated and densified the peat so it looses its porosity and abilityfor "mooratmung". The restoration of the former storage capacity will only be possiblethrough reactivating sphagnum growth. Groundwater seepage is increased by lowering ofhydraulic heads in the surrounding land by artificial agricultural drainage andgroundwater extraction for drinking water supply and sprinkling. Downward groundwaterseepage is the hydrological variable between external hydrological changes and internalhydrological effects. Practical experience in other bog reserves shows that for the prevailingclimatic conditions the long-term average of the downward seepage should not be more thanabout 30-50 mm/yr. The total estimated area with a long-term average downward seepagesmaller than 30 mm/yr is called the Potential Bog Area (PBA). In order to evaluate theeffectiveness of buffer zone measures 41 scenarios have been defined varying in size, shape,agricultural restrictions and management. Partially, scenarios have been generated byoptimization techniques searching for best fits and locations for measures under differenteconomical conditions. The scenarios were evaluated by the transient hydrologic modelSIMGRO that integrates groundwater, soil moisture and surface water. The model wascalibrated and validated to actual groundwater levels and discharge data. Regionalhydrological models as such are rather coarse for ecological objectives as the basic spatialelements of these models are large in comparison to vegetation patterns. To overcome thisscale incompatibility a formula was developed to translate calculated downward seepage fora spatial element of the hydrologic model to PBA depending on variation in hydraulicconductivity of the peat within the spatial element.

Table 3 summarizes some results of the evaluation. The removal of all actual artificialdrainage and sprinkling in the surroundings of the bog reserve will cause a 25% increaseof the potential bog area. The termination of ground water extraction for drinking watersupply and industries will cause a similar increase. Autonomous expansion of drainage andsprinkling for agricultural purposes, however, causes a further 25% decline of PBA. Theimplementation of a concentric 2 000 meters wide buffer zone with a standstill for drainageand sprinklers would reduce the future 25% decline of PBA to only 5%. A smaller bufferzone of 600 meters reduces the future decline to just 18% of the actual PBA. Better solutions


are additional surface water supply from the river Meuse (a 50% increase of the actual PBAinstead of a further decline) and the rising of water tables within the buffer zone. Howeverthat will change water quality. Maximum area with raising of watertables and maximumadditional water supply doubles the actual PBA. Optimization scenarios showed, amongstothers, that the concentric shape of the buffer zone is not the most optimal form.Optimization of the raising of water tables within the buffer zone showed that areas witha high groundwater discharge at 500 to 1000 meters from the bog reserve contributed highlyto the increase of PBA.

Table 3: Calculated change of potential bog area with respect to the actual situation due todifferent water management scenario's

Water management scenario Potential bog area(in % of actual situation)

Termination of all artificial drainage andsprinkling

+ 25

Termination of groundwater extractionfor drinking water supply and industrysupply

+ 25

Autonomous increase of artificial drainage and sprinkling for agriculture - 25

2000 m wide buffer zone with standstillfor drainage sprinkling

- 5

600 m wide buffer zone with standstill fordrainage and sprinkling

- 18

Maximum additional water supply forriver Meuse

+ 50

Idem plus maximum raising of watertable within 2000 m wide buffer zone + 105

3.3.2.2 Nutrient-buffer areas in The Netherlands.

Oligotrophic and mesotrophic ecosystems are suffering from high nutrient loads ofatmospheric deposition and inflowing water. In the Netherlands critical nutrient loads ofall ecosystems are exceeded everywhere. At the same time ecosystems are able to immobilizeor to decompose nutrients. This buffer capacity varies between ecosystems. Landscapeecological research focuses mainly on nutrient buffering in (artificial) wetlands and riparianecosystems (Figure 8).

Two Dutch studies are available for the regional design of nutrient buffer zones for nature


reserves with groundwater fed ecosystems. They differ in scale and methodology. Van Dort& Kemmers (1988) developed a regional model that simulates groundwater transport anddenitrification of nitrogen in a transect along regional groundwater flow directiondepending on agricultural management, topography, geohydrologic parameters, soil types,groundwater depth and denitrification capacity parameters (pH and organic matter).Model calculations result in a buffer width varying from 1 to 400 meters. Model calculationscould be partly simplified to a set of nomograms. Simplification of groundwater transportmodelling was not possible/allowed. Geessink & Bleuten (1992) used almost similarnomograms for a national design of nutrient buffer zones for core areas in the NationalEcological Network (NEN) of the Netherlands. This study also considered transport ofnutrient through the air. The Dutch NEN covers in total 6900 km2 of which 5000 km2

already designated for nature conservation and 1900 km2 to be aquired. For hydrologicalnutrient buffering adjustment of the actual land use would be necessary in another 180 km2

(or 10% extra).

Figure 8: The nitrogen removal efficiency of artifical wetlands used for municipal andagricultural wastewater treatment (Duel et al, 1993)

3.3.2.3 Hydrologic buffer zones in the National Ecological Network of the Netherlands.

The Dutch National Ecological Network (NEN) is an ecological network of core areas,nature development areas and ecological coridors. The NEN includes habitats such as seadunes, north atlantic heathlands, raised bogs, calacareous fens, grasslands and residualalluvial forests. The design of this network did only partly consider landscape fluxes assufficient knowledge on spatial influences of drainage, groundwater withdrawal and


waterpollution was lacking. For instance about half of the NEN is suffering fromdesiccation, which is partly caused by human activities outside the NEN. Nutrient loadsthrough influx of air and water exceed critical ecological load almost everywhere. Althoughthe need for a general reduction of environmental stress through environmental policy isevident, buffer zones will be necessary.

The main objective of this case study was a provisional national design (scale 1 : 250 000)of buffer zones aditional to the NEN in order to buffer influx of nutrients by groundwaterand air and to supply sufficient water. The proposed procedure to design hydrologic bufferzones includes two phases: - the estimation of the need for buffering of habitats within the NEN, - the evaluation of buffer scenario's.

During the first phase the need of buffering is estimated based on the kind and sensitivenessof the occuring habitats, the intensity of the emission and the objectives of natureconservation. The evaluation needs GIS-linked models simulating denitrification andhydrology. Most of these activities can only be operational on a regional scale as for instancesensitiveness of habitats and denitrification vary considerably due to variability in soilcharacteristics and ground water depths. For a national design simple guidelines weredeveloped and applied to national datasets.

The design of national hydrological nutrient buffer zones only ground water fed habitats(ground water seepage areas) were considered to be sensitive to eutrification by groundwater fluxes. An optimal buffering require all land upstream of the core habitats onto thehydrologic divide. A buffer zone width twice the width of the groundwater seepage areawithin the core area is estimated to be sufficient under Dutch circumstances: a annualmoisture surplus of 200 mm, a higher evapotranspiration within than outside core areas anda rather dense surfac water drainage network.

For water retention zones all ground water dependent habitats within the core areas wereconsidered sensitive for dessication. A national design require all land upstream of thosehabitats plus the land downstream until a regional divide. A more exact design that needless land was only operational in regional studies.

The eastern and southern part of the Netherlands with predominantly sandy soils requireextensive areas as most habitats are sensitive to eutrification and dessication. In total 180km2 of nutrient buffer zones and 6250 km2 of water retention areas are needed. As the totalarea of the core areas within the NEN amounts about 7000 km2 the need for buffering andwater retention needs respetively 2.5% and 89% extra land for implementation. Theresearch considered atmosferic nutirent buffering as well but concluded that such largebuffer zones were necessary (estimated order of magnitude: some tens of kilometres) thatthese would exceed practical possibilities.


4 Ecological Corridors

4.1 Definitions

An ecological network is successful if it sustains biological transition and landscapeconnectivity at all levels where fragmentation, isolation and barriers to movements andfluxes are defined. A European ecological network, an international network, shouldintegrate a set of mutually compatible national networks, being completed themselves byregional and local networks in each country. Natura 2000 sites that function as core areasmust inevitably be linked with the wider countryside to allow species dispersion to smallersites. On the other hand species must have the possibility to colonize empty sites within thecore areas if available.

Ecological corridors are various landscape structures, other than patches, of size and shapevarying from wide to narrow and meandering to straight, which represent links thatpermeate the landscape, maintaining or re-establishing natural connectivity. Ecologicallinks between patches have always existed also in natural landscapes. Most obvious aremigration routes for birds, ant-routes, badger routes and river corridors for fish migrationlike for the eel and the salmon. Now most of the ecological corridors are primarily the resultof human disturbance regimes. Their density and spatial arrangement change accordinmgto the human land use. Their connectivity varies from high to low. Nowadays nature needsdifferent types of ecological corridors that have a complementary role to play in aninterconnected habitat island system. Like other land use they need planning.

The term 'corridor' has appeared very early in the literature to refer to long range dispersal(Simpson, 1936). The current use of the term ecological corridor has been recommended byPreston (1960) who has attributed it significant properties in spatial population dynamicsallowing the increase of size and enhancing the chance of survival of smaller populationsbetween preserved patches. The currently expanding field of metapopulation dynamicspresupposes that some degree of connectivity exists between the spatially arrangedsubpopulations within the fragmented landscape.

The nature of ecological corriodors and their efficiency in interconnecting remnants and inpermeating the landscape depend on their origin and the land use mosaic within which theyare embedded and of which they consist: remnants (hedgerows), spot disturbance (railroadand power line strips), environmental resource (streams), planted (shelter beds), andregenerated (regrowth of a disturbed strip) (Forman, 1983).

Four types of corridors are defined:(1) line corridors, which are narrow strips of edge habitat, such as paths, hedgerows androadsides,(2) strip corridors, with a width sufficient for the ready movement of species characteristicof path interiors (for example, a wide power line corridor permitting movement of opencountry species through a forest),(3) stream corridors, which may function as one of the previous two, but which additionallycontrol stream bank erosion, siltation and stream nutrient levels, and


(4) networks, which are formed by the intersection of corridors, this usually resulting in thepresence of loops, as well as subdiving the matrix into many patches.

The participants of the CIFGB-workshop having discussed the different features andcharacteristics necessary to define ecological corridors and agreed on the followingdefinition of ecological corridors in the context of the Habitats Directive:Ecological corridors are landscape structures of various size, shape and habitat compositionthat maintain, establish or re-establish natural landscape connectivity, supporting thefavourable conservation status of species and habitats for which NATURA 2000 sites havebeen designated.

The more complex a corridor is, the more it can be multifunctional. The higherimmigration rate that can help to maintain species number, increase population size,prevent inbreeding, and encourage the retention of genetic variation can be judged as the main advantage of corridors (Simberloff and Cox, 1987). They also increase the foragingarea for wide-ranging species and provide possibilities to escape predators anddisturbances. Of course they also can have negative influences like the breaking of isolationand exposing populations to more competitive species, the possibility of spreading ofdiseases, exotic species, and weeds, and disrupting local adaptations, facilitating spread offire and abiotic disturbances.

4.2 Ecological and spatial aspects of ecological corridors.

Biological transition is a scale dependent phenomenon. Transition occurs in as many spatiallevels as the ones defined by the examined species' ecology and/or the examined ecologicalprocess(es). Consequently, the design of an ecological network would be successful if itsustains biological transition and landscape connectivity at all levels where fragmentation,isolation and barriers to movements and fluxes are defined. A European ecological network,an international network, should integrate a set of mutually compatible national networks,being completed themselves by regional and local networks in each country.

Within the framework of this report, ecological corridors should be defined at twoadministrative levels - paneuropean and national. However, from a conservation planningpoint of view, corridors should be designed at three ecologically meaningful levels: a supra-regional level, a regional level and a local level. Paneuropean (or supra-regional) corridorsshould (a) mainly provide migration routes for species at the European level, either in aseasonal perspective or in view of longer term forced movements related to global changes, and (b) should allow geographic expansion of species. Regional corridors should mainlyprovide access to rescue areas (temporary survival areas for species leaving their shelterareas and habitats), should serve as pathways towards and from the core areas for specieswithin a region and support wide ranging animals. Abiotic processes such as nutrienttransfer or water cycles are also defined at this level. Local corridors should support thebiotic and abiotic spatial processes, flows and movements which are defined at a landscapelevel (sensu Forman and Godron, 1983).

To prevent nature decline by isolation of biotope sites it is important not only to preserve


or develop areas that are large enough for persistence of populations, but also to maintainthe possibilities for exchange of species. That means that important aspects are (1) the sizeof the sites, (2) the distance between them and (3) the absence of barriers (Bischoff andJongman, 1993). Modelling, field research and also nature conservation practice show, thatwithout species exchange apparently vital populations can get extinct on the long run. Thisis not the case for all species, but it is for many vulnerable species. Ecological corridors andstepping stones can be essential for long term persistence of species. Ecological relations arefound to be of all kind, through air, in the water and on the ground. Their spatial scale candiffer from local to continental and global. As the distance between suitable biotope sitesincreases, the number of species that can bridge this distance decreases. Ecological corridorscan be of all kind as well, and that makes it difficult to define them and to realise them inpractice.

An issue that needs to be defined in this context is what constitutes sufficient habitat tomaintain the populations of a species. Favourable conservation status means that speciesshould be components of their natural habitats. The measures to achieve this may requiresubstitute habitats. The Nightar and Woodlark occur in the Breckland area of England forexample. The natural habitat in this area is grass-heath. The local population is dependenton rotational clear-felled areas within commercial forestry. The contribution such areasmake to the viability of the populatin can be extended through the management of the clearfeel areas to extend the period following planting that open ground is maintained withineach felling coup. Equally, to achieve a shift towards a greater proportion of the populationin natural habitats, more such habitats need to be created.

The Habitats Directive makes explicit mention of wide-ranging and dispersal species,particularly aquatic species, for which site-based conservation measures are of limited value. Features of the wider landscape, and indeed the marine environment, are clearly significantfor these species. Corridors encompass the particular landscape features and contribute tothe overall character of an area capable of supporting such species at favourableconservation status.

The following functions are related to the conservation measures required to achievefavourable conservation status:

1. Ensuring adequate breeding success for viability of populations: The example of Nightjar and Woodlark above, indicates a need for substitute habitatscapable of ensuring sufficient breeding success to maintain the population at a viable levelin the Breckland. Many species will require such "artificial" measures, at least in the shortterm, and probably in the longer term.

2. Allowing expansion of existing populations in their natural habitats: Many surviving areas of the natural habitats of species are small: often too small to hold apopulation of the species concerned, or too small to hold more than an insignificantpopulation. Given the aim of supporting populations as viable components of their naturalhabitats, it is desirable to establish sufficient habitat by building on the surviving areas sothat these form the core of the overall habitat available for these species. Corridors insuitable locations will allow the expansion of populations in existing natural habitats. This


meets the objective of dispersal and the provision of sufficient area of habitat in the naturalrange of the species. It should be noted that such a corridor is also likely to act as amanagement buffer for sites containing the natural habitats required for the speciesconcerned.

3. Allowing expansion of populations into areas within their natural range currently notoccupied :

The current distribution of many species is clearly not at favourable conservation status. In such cases measures to secure the expansion of the current range are required. Corridors will provide sufficient habitat to support the populations, and encourage naturaldispersal from current populations to new areas. The following examples should be seenquite generally : landscapes capable of allowing movement from occupied areas, supportingwintering populations so they can populate new areas for breeding, landscapes capable ofsupporting juveniles to allow sufficient survival to breeding so as to allow expansion of therange, and so on, can be seen as corridors. Measures to establish corridors capable ofsupporting the full ecological requirements of a species such that it expands to fill its naturalrange, include the creation and management of features such as ponds, hedgerows, smallwoodlands, as well as the adaptation of management regimes for commercial farming andforestry, and the creation of areas of particular habitats for the species. A corridor for thesepurposes can be defined at a landscape with particular characteristics that make it capableof supporting the ecological function required. This should include the creation of thenatural habitats of the species where this is required. 4. To meet the migration and seasonal movement needs of a species :The Directive is quite explicit that this function pertains to features in the landscape outsidespecial sites. It is obvious one of the main issues not only in strongly fragmented agriculturallandscapes, but at the European level for migrating birds. Routes for species migrationconsist of zones that are accessible for the species to move from one site to another and back.For flying animals this means that this route lacks barriers and that stepping stones areavailable at appropriate distance for feeding, rest and shelter.

Migration routes can be manyfold, from single wooded banks to small scale landscapes andfrom river shores to rivers and coastlines. Migration is a prerequisite for many species fromnorthern Europe to survive the winter period.

Most natural and semi-natural habitats sites are remnants of former natural areas. In thetime that the territory of the EC was merely covered by natural and semi-naturalvegetation, species within these forests and scrubs - in general the less dynamic habitats -had no problems of dispersal or migration. Their biotopes were large and well accessible.Dynamic ecosystems were present as well, but relatively small and the species were adaptedto fast dispersal and colonisation. Now dynamic biotopes dominate the landscape andpopulations of wild species of former large stable biotopes are dispersed over severalsubpopulations in relatively small sites. The single sites are mostly too small to let thepopulation survive on the long run. If one gets extinct it must be recolonised. The speciesis in danger if the area in between becomes impossible to cross (Opdam 1991). Species ofdynamic habitats are better adapted to present land use and survive easily or even increase


in numbers.

5. Allowing populations across their natural range to be ecologicaly integrated: Many populations are now fragmented and isolated, where they have previously been partof a single population. Whilst it may not be possible to fully restore the original range, itis desirable to link the remaining populations so that movement and exchange can occur. Equally, for wide-ranging and dispersed species, where sites make a limited contribution,features in the landscape, and ecological quality across all the habitats used, are the mainconservation measure, supported by direct protection from killing and exploitation. Corridors can assure that such features are present in appropriate areas in ways that allowthe population to function effectively. Feeding areas for bats, and the requirements of manymarine species, are examples.

The potential advantages of corridors include (Simberloff and Cox, 1987):1. higher immigration rate that will maintain species number, increase population size,

prevent inbreeding, and encourage the retention of genetic variation; 2. increased foraging area for wide-ranging species; 3. predator escape cover for movement between patches; 4. a mix of habitats and environmental stages for species that require them; 5. provision of refugia from large disturbances;6. greenbelts to limit urban sprawl, abate pollution, and provide recreation and

scenery.

Potential disadvantages include:1. higher immigration rate that could spread disease, insect pests, exotic species, and

weeds, and disrupt local adaptations; 2. easier spread of fire and abiotic among disturbances; 3. exposure of wildlife to hunters, poachers, and predators; 4. riparian strips might not be used by upland species; 5. cost and possible conflicts with land preservation strategies in protecting endangered

species habitat, if corridor quality is low.

A typology of ecological corridors may be proposed relating to attributes such as shape,position and structure. As an example, in Slovakia the following types of corridors havebeen described: 1. according to their relative spatial position to core areas (biocentres):- conjunctive corridor, connecting 2 core areas,- "blind" corridor, no core area in one end (peninsular wedging, Forman and Godron,

1983)

2. according to their structure:- continuous corridors, without gaps,- interrupted corridors, "stepping stones", "diffusion by jumps",

3. according to their topographic position:- on ridge positions watersheds- in valleys


- on slopes (transversal)

4. according to their shape:- line-like (typical example : ecotones)- belt-like- belt-like for water flows (as specific type of belt corridors)- diffuse (created by a mosaic of different landscape elements without marked

direction)

4.3 The European experience in designing ecological corridors: case studies.

Unlike buffer zones, very little experience exists in practice in applying the ecologicalcorridor principle in the design of ecological networks on a national or regional scale inEurope. The following examples illustrate scientific and planning approaches and the actualstatus of implementation of the ecological corridor principle in ecological network design.

4.3.1 Possible ecological corridors in mountainous national parks in France.

Some national parks in France present excellent interest as case studies of the role ofecological corridors - and buffer zones - in maintaining viable populations of rare species. The national parks of Cevennes, Mercantour and Pyrenees Occidentales have beendesigned following the core areas and buffer zones ring system. The area and the diversityof habitats satisfy, in theory, the species - area and the habitat-area requirements of naturereserve design. However, the shape and the location of the core area is somehow peculiar,although understandable (it follows the abrupt mountainous relief). Figure 10 presentsmaps of the three national parks indicating the core areas and the buffer zones. The coreareas are elongated along altiduninal isolines showing in places bottlenecks which may beconsiderably narrower. For example, the core area of the Pyrenees National Park locallyhas a width of less than 1,5 km even though its maximum width is 15 km. The MercantourNP presents a long axis of about 75 km but the core area is locally reduced to a width of afew kilometres only, serving to connect a series of parallel mountainous compartments. Therole of these parts is more or less that of a corridor for maintaining populations andprocesses may be ex-post evaluated according to the initial objectives of the Park (e.g. targetspecies survival) but also regarding other criteria defined later (e.g. ecological processes,human activities control).

4.3.2 Ecological corridors in the National Ecological Network of Metropolis CentralNetherlands.

The most important metropolis in The Netherlands is called Metropolis Central Netherlands(MCN). This name refers to its ring shape and its location in the central part of the country.The most important natural habitats in the central part of the Netherlands are coastaldunes, woodlands, marshlands and extensively cultivated grasslands (Figure 11). Someimportant ecological problems in this part of the Netherlands are:


- fragmentation of habitats by a very dense infrastructural network, causing a highdispersal mortality among (terrestrial) animals;Figure 10: Maps of the Mercantour, Pyrenees and Cevennes National Parks in France.

NATIONAL PARK OF CEVENNES

NATIONAL PARK OF MERCANTOUR


NATIONAL PARK OF PYRENEES

- isolation of (potential) habitats by extended urban areas, causing local extinctions and lackof re-colonization; - disturbance of nature areas by agricultural and recreational activities possibly causinga decline of local viable populations.

In 1990, the NEN was designed to counter these effects in the future development of the area(Ministry of Agriculture, Nature Management and Fisheries, 1990; Zadelhoff & Lammers,1995). Implementation of the NEN as shown on figure 12 will be realized over the next 15-25years. NEN include various measures: - Fragmentation of habitats will be mitigated by the construction of fauna passages. Faunapassages include fences lining main roads leading into tunnels crossing underneath orecoducts crossing over the road, shallow shores to facilitate the crossing of waterways, andtunnels to cross underneath roads along waterways. The implementation of faunapassages should result in a decrease of dispersal mortality, and facilitate the process of re-colonization. - Isolation of important (potential) habitats (core areas) will be countered by creating newhabitat sites in between existing sites to act as refugia or stepping stones (e.g. new marshes to connect existing marshland areas), and gateways through municipal areas (woodlotsand wooded banks connecting existing woodland areas). These measures should result ina network of corridors connecting four important marshland areas (Oostvaardersplassen,Vechtplassen/Nieuwkoopse plassen, Biesbosch and Gelderse Poort) and three importantwoodland areas (Veluwe, Utrechtse Heuvelrug and coastal dunes), facilitating re-colonization of potential habitats and exchanges of individuals between existing viablepopulations or re-introduced populations. - Effects of disturbance will be lessened by enlarging important existing nature areas andimproving their habitat quality. The last is to be accomplished by changing an area's landuse type: the multi-functional woodlands of the Veluwe will become natural grazed woods,and currently intensively cultivated grasslands will change to extensive cultivation. Thesemeasures may also compensate for increased fragmentation elsewhere. A sufficiently largeincrease of habitat area may compensate for its isolated location. Larger habitat areas willincrease the probability to maintain viable populations and the possibilities to succesfullyre-introduce species in vacant habitat areas; habitats of higher quality may be suitable formore species and thus increase an area's bio-diversity.

The effects of the implementation of the NEN on connectivity were evaluated ex ante by theLEDESSystem (Harms, Knol & Roos, 1995). This system comprises modules for modellingthe suitability of habitats (SHAPE) and the dispersal (GRIDWALK). The models wereapplied to seven mammal species representing marshland areas (beaver, otter), woodlandareas (pine marten, red deer) and extensively cultivated areas (polecat, red fox, badger). Thefollowing points summarize the results of the study:

_________


Next page:Figure 11: Metropolis Central Netherlands, actual habitats and National Ecological Network(NEN)


- The main impact of NEN appears to be the increase of habitat area, which may be largeenough to succesfully re-introduce some of these species. - NEN's proposed wet corridor connecting Holland's important marshland areas may haveless impact on connectivity than expected. The current design contains too few details tosufficiently facilitate re-colonization of core areas for marshland species. Another reason forthese unexpected results can be technical. Marshland species may tend to disperse betterthan is simulated in GRIDWALK as they migrate more selectively, e.g. by following waternetworks. NEN appears to have small impact on the dispersal possibilities of marshlandspecies. Although habitat sites increase in size, and new sites are created, populations thatareconnected in the current situation tend to remain so after completion of the NEN (figure13). - For woodland species the newly planned habitat sites appear to be essential to eventuallyconnect the central and eastern parts of the Netherlands to the coastal area, and to a lesserextent, to the south. The largest impact on connectivity of NEN was found for the speciesof woodlands. Figure 14 shows dispersal patterns for one year of red deer, originating fromthree currently existing populations on the Veluwe and in the Oostvaarders Plassen, andone hypothetically re-introduced population in the coastal dunes. In the current situation,the coastal dunes are not connected to existing populations. After completion of the NEN,the newly created habitats provide stepping stones to connect these areas in the course ofseveral years. This is the case for the pine marten as well, although the implementation ofNEN causes some of the habitat sites in the coastal dunes area to decline.

- Common species such as the polecat and red fox appear to have adapted to the currentsituation and are able to exchange individuals between existing populations and colonisenew habitats already. However, NEN will facilitate these processes and provide larger andmore habitat areas for these species as well. For the species of extensively cultivated areas,the NEN mainly results in better dispersal to the north- and southwest due to new habitatsites. Figure 15 shows the dispersal patterns for one year of the polecat: new habitatsnorthwest of Amsterdam and in the Biesbosch area are colonized.

4.3.3. Landscape elements as corridors and buffer zones in Madrid region, Spain.

A first proposal for an ecological network in Madrid region is currently under development.This potential ecological network should include a set of core areas, connected throughvarious types of corridors and/or buffer zones. Mountain ranges and wetlands associatedwith underground water are planned as nodes of the network, whereas more or less linearlandscape elements (riparian forests and drover's roads) and low intensity agrarian systemsshould function as corridors and/or buffer zones. More explicitely (Mugica et al., 1995):________next pages:

Figure 13: The dispersal of beaver with (a) and without (b) NEN

Figure 14: The dispersal of red deer with (a) and without (b) NEN


Figure 15: The dispersal of polecat with (a) and without (b) NEN




1. Core areas:

Mountain ranges.Sierra of Guadarrama is the main mountain system in Madrid region. About 1500 plantspecies, birds of prey such as black vulture (Aegypius monachus), imperial eagle (Aquilaheliaca), golden eagle (Aquila chrysaetos) and red kite (Milvus milvus) are some of thevaluable samples of biodiversity of this mountain (CIFGB, 1995). In Madrid region,mountains have played the role of refuges for flora species due to the cooler and wetterclimate with respect to the lowlands. This has caused the existence of isolated populationsand a high level of endemism.

Preservation of natural values has been possible due to climatic features, shows relief andpoor soils which have reduced the possibilities of intensive agriculture development. Actualprotection of mountain ranges is needed in order to guarantee the functionality ofequipotential processes (physical connections between landscapes) and vectorial processes(slope effect, erosion processes, and so on). The importance of the area has been recognisedby the establishment of some patches as protected areas. However, it is necessary to includebuffer zones and corridors. Prieto and De Lucio (1993) noted that several communities offauna and flora located on the top areas are endangered due to their reduced andfragmented distribution. Therefore buffer areas are needed: corridors to allow themovement of some populations of fauna to the corner part of the valley, refuges, breedingareas for passerines in the pine forests and birds of prey, etc., are also needed. Theproposed areas include mainly public lands. In fact, close to 80% of Guadarrama area ispublic land, which makes easier, at least in theory, the management of the mountain area.

Wetlands associated with underground water: evaporative discharge habitatsWater supply from the underground is, in many Mediterranean areas, the key factor for thesurvival of many species during the summer period. Aquifer discharge takes place asvapour through the vegetative surfaces, the existence of liquid water not being visible; theybehave as habitats of evaporative discharge (Gonzáles Bernáldez et al , 1985). Zones ofdischarge due to evapotranspiration in the Madrid aquifer, with a surface of 3,700 Km2, areparticularly important in the configuration of the landscape. Soil humidity means a richervegetation, fauna and land uses with respect the surroundings (GonzálesBernáldez et al ,1989). In spite of the quite small surface of vegetation associated with the zones of localdischarge, the density of discharge in the territory is relatively high. Moreover, theseformations are the more characteristic representatives of wet elements in a country poor inlakes like Spain. The interest of these sites can be found in the great dynamism whichimpose particular biological adaptations to their species (Alonso, 1987; González Besteiro,1992). The ecological importance of evaporative discharge areas in arid zones, andparticularly Madrid region, was pointed out by Gonzáles Bernáldez et al, (1985): thedifferential energy sink effect, their contribution to landscape diversity, their biogeographicinfluence and biological diversity due to hydrological changes caused by infratructure(motorways, pipelines, etc.) and water pumping may be observed in the Madrid aquifer.

If these areas are kept in a good conservation state, they will represent a good system ofrefuges for many animals. Important numbers of fauna including birds, mammals, insects,etc., of the Madrid region depend, to a large extent, on the distribution of the aquifer


discharge zones (Sterling, 1990).

2. Ecological corridors

Riparian ForestsIn Mediterranean or semi-arid climates the main forested corridors are "sotos" or riparianforests. Riparian forests are naturally linear or sinuous features with well-known habitatand ecological values: high biological productivity, microclimates moderated by thepresence of water etc. (Sterling, 1990,; Noss, 1993). In the Madrid region they constitutesmall wet islands within a rural landscape. In spite of their reduced size, they representhabitats of high biological richness. Moreover, they are structures which increase betadiversity. The higher the environmental contrasts, the more important is the landscape andbiological variety. In a study carried out in River Guadarrama, in Madrid, Sterling (1990)found that the number of bufferfly species is triple in the riverine forest as compared to thesurrounding land. Species such as Melanargia lachesis and Iphiclides podalirius areconcentrated in the "sotos" using them as aestival refuges. Others such as Limenitis reductaor Inachis io, characteristic of mountain environments, can be found at lower altitudes inthe riparian forests. With regard to birds, Mediterranean riverine systems act as refugesfor Eurosiberian bird species, e.g. Erithacus rubecula, characteristic of zones above 800 mbut found in lower and more arid zones where riverine forests exists. Mammals such asApodemus sylvaticus and Elyomis quercinus are more abundant within the "soto" thanoutside (Sterling, 1990).

Riparian forests are also migratory routes for species of fauna and flora associated with wetenvironments, especially in those cases where the valley's main orientation coincides withthe direction of the main migratory routes. This is particularly probable for some rivers ofthe Madrid region such as the Henares, Jarama, Manzanares and Guaderama rivers, whosegeneral orientation is North-South (Sterling, 1990).

Drovers' roadsThe great interest of livestock roads for nature conservation in the Iberian peninsula hasbeen recognised. These roads made possible the transportation between uplands andlowlands during the year depending on weather and quality and availability of pastures(Pineda et al, 1991). Today, when trashumance in Spain has seriously declined, these roadsseem to be useful as ecological corridors and ways to connect natural habitats.

The network of drovers' roads in the Madrid region has a great potential for natureconservation, being also adequate for recreation and education in a territory where thesedemands are growing day by day. Its location, in the centre of the Iberian peninsula, thegeographic variety from mountains to lowlands, and the historical and economicimportance of the Madrid region, have configured this land as a cross-way of big drovers'roads which cross the Peninsula from north to south: four of the nine main Spanish drovers'roads cross the territory of Madrid through more than 4000 Km. The Madrid region hasthe second largest, after the province of Valladolid, surface of resting and watering placesfor cattle.


As a result of the decline of traditional uses linked to trashumance, drovers' roads havesuffered the abandonment and alienation of property which have contributed to thefragmentation and loss of this natural and cultural heritage. Although there is not muchscientific research evaluating the role of this structure as ecological corridors, there is nodoubt that not so long time ago the livestock migrations were accompanied by predatorsand carrion-eating species such as wolves and vultures; an interesting flora of herbaceousplants appears on these roads (Pineda et al, 1991).

Inclusion of these structures in the conservation network must be understood in terms oftheir roles as corridors, which implies the existence of legal regulations to guarantee theirfunctionality (CIFGB, 1995).

Agrarian systems of low intensity.Dry-farming and wooded pasture lands are agrarian systems characterized by a lowconsumption of fertilisers and agrochemical products, and so compatible with the needs ofprotection and conservation of natural environment. Among the values of pasturelands onecan note a high turnover and productivity rate, an ability to maintain high species diversity,cultural values and potential for playing a role in the system of nature conservation (Pinedaet al, 1991; Gomez-Sal et al, 1992).

Natural features of Madrid region are not suitable for the development of intensive andprofitable agriculture and so there is a good representation of this kind of low intensivesystem (GIFGB, 1995). Lowlands and steppe areas of Madrid South and Southwest areparticularly valuable due to the presence of birds such as the great bustard (Otis tarda),included in several European directives and conventions (Birds Directive, BernConservation, Bonn Conservation, CITES). In Spain the bustard is protected since 1980. In Madrid region there is a fragmented population threatened by the construction of amotorway which will cross the territory occupied by the bustards. The area where thepopulation is found belongs both to the Madrid region and the Guadalajara province. Thisis a new case of inter-regional concern.

Migration of rural populations to urban centres and abandonment of marginal agriculturalland have caused the disruption of the equilibrium between natural and human processes(Pineda et al, 19991). In the Madrid region agrarian systems are strongly affected byspeculative pressures, forestry exploitation, second home development, tourism, recreationand water catchment uses. Promotion of extensive agriculture linked to traditional uses isvital for the conservation of high natural values and biological and landscape diversity(Pineda, 1992).

5 Criteria and procedures

5.1 Ecological networks in Europe

Ecological networks are based on nature conservation policy objectives, and approaches are


derived from these objectives. Nature conservation objectives are based on ecologicalprinciples, but can be interpreted differently because of differences in ecological conceptsthat play a role in the national or regional policy. They vary from the conservation ofspecies to the conservation of natural and cultural landscapes. Due to a difference in natureconservation history national strategies show great differences in Europe, but the policyobjectives are more or less comparable: the protection of species and areas of high naturalvalues in designated areas. However, differences in policy are expressed in the way natureconservation is implemented. Countries with strong planning traditions do approach natureconservation problems in a different way than those countries that lack planning traditions.Objectives may be comparable, the function of the planning can differ strongly. Three levelscan be distinguished, the European, the national and the regional/local level. Most of thenetworks are part of the national or regional nature conservation policy, some are stillproposals or desk studies (Table 4).

In many countries nature conservation has a long development. It has become a field ofpolicy and is gaining force especially in the last decade. Knowledge and concepts fromlandscape ecological research found their way into nature conservation policy strategies.The development of coherent spatial structures is the most obvious part of it and ecologicalnetworks became an important strategy in nature conservation in The Netherlands,Flanders Denmark and Germany. In the Central and East European countries integratedplanning has a strong tradition. Nature conservation as a independent policy had a minorposition, but it developed in the framework of physical planning and other forms ofintegrative planning. In this framework elaborated ecological networks have been developedconsisting of several hierarchic levels.

National and regional networks have comparable structures. They consist of core areas,corridor zones and buffer zones and have a basis in metapopulation theory and islandbiogeography theory. The networks are hierarchical structures on national to local level.The Danish "Regionplan" functions only at the regional level. Differences in planningsystems and national or regional priorities make it difficult to relate the national andregional planning systems for nature. A first attempt to relate national strategiessystematically has been discussed at the conference on European coastal conservation (Udode Haas and Vertegaal, 1991).Two regional European studies have now been carried out,by the IUCN for the Central European countries (Czech Republic, Slovakia, Hungary andPoland and one for the Benelux (Jongman and Van de Windt, 1995). In many countries insouthern, central and eastern Europe nature conservation strategy is now in a pioneerphase. The planning system and the legislation for nature conservation and related landuses is in development. Natura 2000 can be at one hand the incentive for governments todevelop a nature conservation policy, on the other hand national policies can enforce theEuropean network by developing spatial coherence. It is this process of mutual enforcementthat has to be started and that possibly will lead to a coherent ecological network for allEurope.


Table 4. Examples of ecological networks at the national and regional level in Europe, a shortindication is given of its approach and function based on the texts in policy documents orresearch reports (after Jongman, 1995b).

name of the network Concept/approach

National Ecological Network (TheNetherlands)

policy document aiming at conservation of species in acoherent areal structure at the regional level

Ecologische en Groene hoofdstructuurNoord Brabant (The Netherlands)

policy document aiming at conservation of species in acoherent areal structure at the regional level

Nature frame of Lithuania system for land management to preserve and create anenvironment for both conservation and restoration of nature

Territorial system of landscape ecologi-cal stability (TSLES), Czech Republic

network of ecologically important landscape segments basedon functional spatial criteria aiming at the preservation ofbiodiversity, conservation of nature and supporting multi-functional land use

Territorial System of Ecological Sta-bility (TSES), Slovak Republic

network of ecologically important landscape segments basedon functional spatial criteria aiming at the preservation ofbiodiversity, conservation of nature and supporting multi-functional land use

Groene Hoofdstructuur van Vlaan-deren (Belgium)

coherent structure of areas in which nature conservationpolicy is the main objective

Network of compensative areas(Estonia)

planning and management of rural areas aiming at optimaldiversity of landscape pattern and ecological infrastructure

Vernetzter Biotopsysteme (RheinlandPfalz, FRG)

planning concept for conservation of nature and naturalcommunities, development of core areas and corridors andto conserve species

Zonas de interes potencial para la red"NATURA 2000" en el estado Españoland EECONET in Spain

tentative proposal for natural areas to be part of NATURA2000 based on criteria of biodiversity, size representativity,vulnerability, endemism, management and an indication forpotential ecological corridors

Design of a Nature reserve system inGreece

design of a system of nature reserves to protect species andspecies assemblages against extinction and breakdown

Naturområder /økologisk forbindsele(Denmark)

core areas and ecological corridors in regional plans (Amte)

Green lungs of Poland plan for sustainable development in Poland in relation withits eastern neighbour countries

Because national policies play an important role both for planning and for science it isobvious, that most ecological networks have been designed at the national level. Nationallevel is meant as an organization level. Especially in central eastern European countriesintegrative planning is the traditional approach and these networks are not restricted to thenational level, but do include the regional and local level as well. In these countriesdiscussion and decision making on changes in ownership, land use and nature conservation


policy include ecological networks as an important aspect.

In some countries like Germany, Spain and Belgium the actual responsibility for natureconservation is not at the national level but at that of the member states within thefederation or the regions. That means that developments can differ within a country. InGermany Rheinland-Pfalz is developing ecological networks at the regional level (Burkhartet al, 1995). For Niedersachsen at the moment only desk studies are available. In Spain inCatalunia the regional government is taking its responsibility by active development of anature conservation policy based on the ecological network principle. Also in Denmark theregional governments have a major responsibility for nature conservation and regionalcommittees (Green Councils) play an important role in decision making (National Forestryand Nature Research Agency, 1992). The Danish physical planning system includes arealclaims for nature conservation and it is mainly the responsibility of the counties (amte) torealize them. These differences within countries cause differences between regions inpriorities and in development. National or international co-ordination does not seem to beof such great importance for the local and regional public awareness and involvement.However, Brandt (1995) concludes from an evaluation study that many corridors have beenplanned, but only few have been implemented and due to the emphasis on the regional levelnational coordination is lacking.

Coordination or integration of the local, regional, national and international level is animportant aspect for policy making. The integrated planning systems seem to have anadvantage in this matter. However, the short nature conservation history, the complexityof integrated planning and the political changes in most of the central European countriesmay hamper the success of this planning system. The Dutch system seems to be complex aswell, but it appears to function and even larger projects are getting started. The Danishapproach, a strongly decentralized policy, shows to be very successful to realize smallerprojects, but also here larger projects are initiated and co-ordinated at the national level.

5.2 Implementation of ecological corridors and buffer zones

As mentioned before, the concept of buffer zones is rather old. Although in theory, nationalparks or nature reserves world-wide are very often designed following the general model ofconcentric rings, in practice there is a large gap between the model and its implementation,even for UNESCO's Biosphere Reserves (Tangley, 1988). Two major features of the land-use conflict over the adjacent lands may be defined:

The timing of application of the conservation plan, where buffer zones are designed.The land-use conflicts become inevitable when adjacent land-use zones are not created atthe time the national park or biosphere reserve is first established

The lack of integration of conservation into the regional planning. The relationships between core protected areas and their adjacent or surrounding areas isprobably the major management challenge of planning today (Nelson, 1988 in Shafer, 1990).Experience throughout the world suggests that while there is a definite need to integrate theplanning of national parks and other protected areas with regional plans, this need is not


perceived by managers as being critical (Eidvik, 1984). Long-established traditions havefixed a management style in which governments and non-government organisations haveconfidence that the parks can best achieve their objectives under present managementregimesPractical experience regarding ecological corridors is very limited. What we really knowabout what constitutes a good corridor and how to design and manage it, is asthonisinglylittle. Although it is logically assumed that width and connectivity are the primarycontrolling characteristics of an ecological corridor (Forman, 1987) and beyond theintuitively stated pro- (e.g. Harris, 1989) and con- (e.g. Simberloff and Cox, 1987) ecologicalcorridor advocacy, it is remarkable that solid scientific documentation on the followingquestions is badly lacking:

1. what is the degree to which various species would use corridors ?It is suggested that riparian forests or woods may be the best solution for designing anecological corridor in very modified landscapes. There is no evidence that a non riparianspecies may find or not find a riparian habitat corridor to its liking (Frankel and Soule,1981).

2. what constitutes a barrier or a corridor for a species ?Life-history strategies and the spatial scale on which species realize them are critical for thedesign of an ecological corridor (Forman and Godron, 1986). For example, large mammalsneed connectivity on a large spatial scale continuous natural habitat. Small vertebrates andmost invertebrates may be effectively isolated by roads or even small incursions ofunsuitable habitat. Plants are dependent on other species and mechanisms as wind andwater for dispersal. Succesful dispersal depends on the availability of these mechanisms anda suitable habitat for colonization. For them the dispersal mechanism is much moreimportant, because of their undirected transport mechanisms. I northwestern Europe mostof the rivers and brooks have been regulated and these do not flood any more in winter andspring. That means that the most effective dispersal mechanism has disappeared. Nowplant species are much more dependent of other transport like fauna, wind and man.

ture, barriers inducing isolation occur in different forms. Landscape features, either natural or man-made may act as general barriers indifferently for all or most of the organisms or selectivelyfor some of them. Examples of barriers of natural character are borders between differentgeoecosystems (wet-dry, cold-warm, terrestrial-aquatic). Ecotones may form eventuallysemi-natural barriers, as for example borders between forests and agricultural land.However, ecotones may also be very important corridors. Man-made barriers have apronounced technical character: e.g. urbanized areas, transport lines. Usually they arebarriers for genetic flows for most terrestrial and aquatic species. Man-made barriers arebeneficial for anthropochorous species (Miklos et al., 1995)

Ecological corridor design experience is in practice limited by the gaps in ecological theoryon what factors influence the movement of a species and by the lack of planning guidelinesfor ecological corridors. For example, we do not really know what are the fundamentaldifferences between maintaining or re-estabilishing landscape linkages and creatingpreviously non existing connections.


Nevertheless, ecological corridor design may be one of the most important single challengesconservation and regional planning face. There is apparent concensus around the need forecological corridor: the statement that "in the face of scientific ignorance about thesephenomena, maintenance of habitat connectivity would seem to be the prudent course" hasgained wide support (Noss, 1987).

Figure 16 summarizes the degree of magnitude of spatial requirements. Water supply areasrequire the largest tracts of land (hunderds to 1000 kilometres). Corridors to providemigration of terrestrial mammals vary from tens of kilometers (hedgehog, red deer) to somehunderds of kilometres (Otter, Elk, Wolf, Bear). Buffering of atmospheric deposition sometens of kilometres. Water retention tens of kilometers. Hydrologic nutrient buffering andmigration of small mammals requires relatively small tracts of land (meters to hundreds ofmeters).

Figure 16: Order of magnitude of spatial requirements for nature facility areas

5.3 Procedural guidelines

The fundamental assumption of this document is that Natura 2000 sites are representativesamples of Europe's biodiversity. Species and their biological characteristics and ecologicalprocesses within the sites have to be subjects of protection and management in order toform a stable ecological network according to the previsions of the Habitats and SpeciesDirective. Buffer zones and ecological corridors are management objects which may benecessary to ensure the conservation status of species and habitats within the Natura 2000sites. The following methodology flow diagrams (I, II and III) present the logical paths for


analysis of ecological and biological data which are necessary to assess if the full range offunctions a landscape or marine area needs to be capable of fulfilling to achieve favourableconservation status for the species involved is covered. There is a need to consider featuresrequired across areas, and set out the overall character of an area which is necessary toachieve favourable conservation status. This will include consideration of the full range ofecological needs of the species involved, including movement, dispersal, migration andgenetic exchange. Buffers and corridors refer to the specific and positive requirements forhabitats to meet the full ecological requirements of particular species so that favourableconservation status can be achieved.

Regarding the planning process, the following steps describe an orderly suite of phasesin relation to the Habitats Directive prescriptions:

1. Favourable conservation status needs to be defined as the starting point. That canbe different for all Natura 2000 sites, because most will be a complex of habitattypes of different sizes and with different characteristics and species composition.The objective must be clear that it is possible to derive guidelines for themanagement of:

- species:(1) habitat quality, (2) habitat size and (3) possibilities for exchange- abiotic features from the wider environment, (1) vital inputs and (2) pollution from water,and air or- human impact through land use and traffic systems.

2. The contribution of protected areas to favourable conservation status of species andhabitats needs to be established and the conservation objectives of each site mustbe analysed in the light of this. This is comparable to an analysis of strengths,weaknesses, opportunities and threats.

3. Optimization of the conservation status might need action by enforcing strengthsand opportunities, diminishing threats and preventing development ofweaknesses.

Strengths and opportunities are the positive aspects of a conservation area. These can belinked to the objective of the Natura 2000 site but also to its location. The strength of a sitecan be its very vital population, and the opportunity can be that there are possibilities toenforce the functioning of the site for the wider countryside because there are many emptyniches or a good network of corridors for dispersal exist.

Weaknesses can be both internal and external. An internal weakness can be the shape of thecore area or the small size of the key populations in it. An external weakness can be thedistance between the core area and forgaging areas outside for migrating species.

Threats are always external but can be introduced into the core area, like recreationfacilities near a vulnerable site or population. External threats can be abiotic e.g. pollutedwater, or anthropogenic, e.g. land use.

4. Other measures to meet the ecological requirements of each habitat and species to


achieve favourable conservation status will include specific contributions fromoutside protected areas, and these can be described in terms of landscapecharacter and features. This can be as buffer zones including particular bufferingsystems as "managed retreat" for flood defense, particular uses for set-asideland, and so on. Corridors and stepping stones should be defined as the featuresand characteristics of the main land uses in the area contributing to theconservation status of the species an area supports or should support.

5. Wider threats to the conservation status of wild species and natural habitats are thefinal isuues to be identified. These are likely to be best addressed by wider policymeasures reducing the challenges to the environment or to the species concerned.These are administrative measures controlling the activities and methods usedby organisations and individuals where these affect the conservation status ofhabitats and species.

5.4 Planning challenges

Buffer areas relate to specific sites with particular needs. They should be shown to addressparticular issues that affect the achievement of the conservation objectives for the site. They should be the best means for addressing these issues at the particular site. This mayrequire specific policy support at a wider level, and this should be identified in theassessment of the suite of measures needed to achieve favourable conservation status. It isimportant not to use buffer areas site by site when wider policy development is a moreefficient means of securing the conservation goals that have been set out.

The Habitats Directive refers to corridors and stepping stones. We need to be neutral asto shape and extent of corridors: one important contribution they can make is to ensurethere is sufficient habitat to maintain populations across their natural ranges. This willrequire decisions on location, management and pattern. This is clearly flagged in the BirdsDirective (article 3(2)(b), (c) and (d)) and is implicit in the Habitats Directive.

However, the planning process should take into account specific needs and/or limitationsthroughout the implementation region(s). The spatial requirements differ regionally andbetween kinds of buffers and corridors. A set of criteria to delineate buffer zones andcorridors is difficult to generate. Thus, a need emerges for a planning procedure thatintegrates the needs of different kinds of buffers and corridors and links their different typesto different hierarchical planning levels. The allocation of nature facility areas from aEuropean to a national scale should focus on those buffers and corridors that need largeareas and distinct landscape features. For other buffers and corridors just global indicationof width, shape and allocation is sufficient at the European and national planning level.Further elaboration on regional scale, however, is necessary as regional characteristics canvary in size, shape and allocation considerably.

There are differences between countries depending on land use history and presentagricultural policy. Economic conditions as overproduction in most basic food products andfree market rules are driving forces for land use changes. It can be seen now already and


is expected to continue in the future that agriculture retreat from large areas (NetherlandsScienticfic Council for Government Policy, 1993). The common agricultural policy (CAP)of the European Union but also the official environmental policy of the Ministry of Environ-ment and the Ministry of Agriculture of the Czech republic are now beginning to bedirected on the reduction of subsidies on agricultural production and slowly to supportlandscape multifunctionality and to keep traditional settlements in the rural landscape. Itis estimated that in the Czech Republic about 15 percent of the total agricultural land willbe available for set-aside programmes (Jongman et al, 1995). Regional differences in landuse development depending on natural conditions, especially on soil fertility and landsuitability for agricultural production will be emphasized in this way.

Directing this change in land use also according to nature conservation objectives mighthelp to develop supporting systems for nature conservation areas and especially for Natura2000 sites. Nature conservation objectives can be used as a guiding principle for land usesupport to farmers in sensitive areas. That allows farmers to get an income and preventsland abandonment.

In intensive farming areas the preconditions for nature conservation could havefar-reaching consequences for the management of the agriculture. Van den Aarsen (1994)showed that in the Netherlands the implementation of ecological networks means areduction in acreage, the necessity to reduce the release of nitrogenous compounds andphosphate, the use of groundwater and the requirement of space for the creation ofstepping stones and corridors.

The means for implementing ecological corridors are good in terms of future space, but theyare limited in financial and political instruments. The possibility exist to stimulateextensification of agricultural land use through the policy of Environmentally SensitiveAreas (ESA). However, the number of ESA schemes that can be supported by CAP is stillrestricted. Structural support for buffer zones and landscapes with a corridor functioncould help greatly to reach the favourable conservation status.That means that the futurescenario given by the proposed ecological networks gives a nice outlook towards a betterfuture, but that the road to get there is still under construction.

Evaluation of nature conservation practice can be based on either an ex-ante or an ex-postapproach. Ex-post evaluation is based on monitoring ecological characteristics afterexecution of certain nature conservation measures. This approach evaluates the aims ofthese measures by (statistical) analysis of monitoring data. Ex-ante evaluation is based onsimulation of expected effects on ecological characteristics before the execution of natureconservation measures. Both expert and simulation models can be applied in ex-anteevaluation. Practical experiences in evaluation of spatial conservation measures are veryscarce in Europe due to both practical (few plans executed so far) and methodologicalreasons. This is true, even in countries with expertise in this field such as The Netherlandswhere well-documented ex-post evaluations of nature facility areas are largely lacking.However, a lot of ex-ante evaluations of most functions of buffer zones and ecologicalcorridors are available.

A review of ex-ante evaluations of buffer zones and ecological corridors show that


knowledge of spatial requirements (size, shape, position within land system, management)for most kinds of them are available. Those spatial requirements differ between the variouskinds of buffers and corridors.

The planning of buffer zones and ecological corridors within the framework of theimplementation of the Natura 2000 network will face several difficulties ranging from thelack of well established practical design guidelines to the limited efficiency of the existingnational conservation law system. The following points are identified under the assumptionthat ecological corridors and buffer zones should be viewed primarily as land useregulations integrated within a regional plan.

1. Defining conservation targets within sitesMost of the habitat types included in the Annexes of the Habitats Directive and even morethe Natura 2000 sites are defined in a way covering an extraordinary variable ecologicalcommunity, presenting over large scales complex mosaics of distinct subcommunities. Main question and challengeHow the spatial heterogeneity, the time variability and the community dynamics will beassessed in order to avoid mis-interpretation of their distribution and/or overviewing areasthat may have long-term conservation values?

2. Fragmentation: remnants and sizeThe various habitat types and species listed in the Habitats Directive present a geographicdistribution which, by definition, is severely fragmented as a consequence of either theirnaturally patchy occurrence or the large scale modification of the landscape over theirrange. Species occurring in coastal areas or along basin drainages are those that especiallysuffer from urban and agricultural encroachment. Consequently, habitat patch sizes arehighly variable and small sizes are predominant among the remnants likely to form the coreareas.Main questions and challengesa.The role of ecological corridors becomes crucial in connecting the small sized core areas.There is an urgent need to develop guidelines for the design of ecological corridors and fortheir integration in the regional planning process.b.The SLOSS debate (Single Large Or Several Small reserves) requires elaboration:"many" and "large" should be considered in conjunction with other issues that parallel theSLOSS debate: proximity/barriers, corridors, coverage, genetics, and shape.

3. Land ownership.The implementation of conservation planning, especially the design of an ecological network(ecological corridors, landscape linkages and buffer zones), lies in the capacity and legalityof the State's authorities (Central Government, Local Governments, Regions, Agencies,Public Enterprises etc.) to control and impose land use over public and private land.Presupposing that the land ownership status is established in an area (meaning that OfficialCadastral plans exist), the design of ecological corridors and buffer zones appears primarilyas a matter of land use regulations within a framework of competing interests on public landand of constitutional prohibition of confiscation or uncompensated public use of privateproperties.In The Netherlands the implementation of the national buffer policy stagnated due to the


huge area of agricultural land required. Nowadays there is no official buffer zone policy asobjectives are integrated within water management plans. The introduction of ecologicalcorridors in The Netherlands is more succesfull as it requires (in the chosen design) less landand it is incorporated in land consolidation plans and infrastructure (re)constructionplans.In central and eastern Europe the change in land ownership is a both a challenge anda threat to the implementation of ecological corridors and buffer zones.Main questions and challengesa. Does the competent State Authority for conservation planning possess:- cadastral plans of the area under planning indicating which lands (at a parcel-by-parcellevel) are public property and which are privately owned?- the legality of zoning or general planning, and under which mandate (National, Regional,Local, European) if the lands affected are privately owned?b. What is the structure of the land ownership on the landscape scale appropriate for theneeds of the design of ecological corridors and buffer zones? The structure of the landownership becomes a crucial factor for planning buffer zones and ecological corridorsbecause it determines the possibility of establishing co-operative approaches between theowners themselves and the planning authority. Few land owners mean large proprieties andsmaller differences in individual willingness to participate in the conservation process. Alarge number of owners makes in practice any attempt to create a common approach toconservation priorities impossible.c. What are the interactions between the structure of the land ownership and theGovernment level at which conservation planning is decided? Land use conflicts are mostlygenerated by large scale policies (e.g. agriculture, tourism etc.). If the conservation planningprocess has to deal with hundreds or thousands of land owners, although intimatelyconnected with land use regulation, regional or local level authorities would not have theability to resolve such conflicts. Because these authorities have very little impact on centralpolicy making, they do not influence the fundamental trade-offs between conservation anddevelopment.d. What is the nature conservation value of private lands. Often private land is poorlysurveyed for biological resources and can be an important refuge for threatened species.

4. Multiple jurisdictions.Multiple jurisdiction is involved in conservation policy design and implementation.Responsibility for nature conservation is organised differently in different states. Somecountries have regulations at the national level, even in the nature conservation law onecological networks, ecological corridors and buffer zones. Other countries have a welldeveloped planning system and some have none. Moreover, the political strength and theacceptance as a policy field differs greatly through Europe. In general three organizationlevels are particularly important.Main questions and challengesa. Central Government: There is little coordination among the ministries that are principallyresponsible for protected areas, or that are influencing or affecting natural resources. Forexample, in Greece, without being complete the following Ministries and/or Public Servicesmay be involved in the decision making and the management scheme of protected areas:(a) Ministry of Agriculture, Forest Service(b) Ministry of the Environment,(c) Ministry of Marine Affairs, Directorate of Protection of Marine Environment,


(d) Ministry of Culture, Direction of Protection of Monuments,(e) Ministry of National Economy, Directorate of Regional Planning,b. Regional Authorities, Local Governments: at a regional or even local level, the centralgovernement policies have to be adapted and implemented by a second level of decisionmaking and planning. In many countries, Spain, Austria, Germany, Belgium Denmark andthe Netherlands nature conservation planning has been decentralized. That means that theregional governments carry out the policy and are responsible for implementation. Theirrelation with the central government and their power is of great importance for theefficiency of nature conservation policy in Europe. This now already leads to differentdevelopments in different regions.While in many countries local government may have the statutory authority to deal withland-use designations and issues, it has critical limitations. The local government is seldomprepared to develop the policies necessary to provide for effective, scientifically defensibleconservation programs. Local government traditionally serves urban needs and often lacksstaff trained in conservation planning. Moreover, its authority is by definition limited toa specific jurisdiction, and local government simply cannot provide the regionalcoordination of plans necessary to meet effective conservation goals.c.Protected areas are located within different administrative jurisdictions.The planning area where the integrated planning process should be implemented mayinclude many local jurisdictions, cities and natural areas of different level of developmentand face different on-going land-use approval processes and, of course, pressure forimmediate development. Involving all of the jurisdictions in one comprehensive planningeffort may be the most critical feature of the process of participation of people. Thisproblem is very acute in the case of ecological corridors and buffer zone design.

5. Insufficient implementation of nature conservation laws. In practice, all European countries have already adopted a nature conservation

policy specified in numerous laws, Conventions and international agreements.However, claims for strengthening the implementation of this legal frameworkare emerging everywhere. For example, in Greece, where the two first NationalParks have been created in 1938, and although the authority exists since 1971 forpromulgating them, specific regulations for each national park do not exist.Furthermore, operating policies, guidelines and procedures for carrying out theday-to-day protection of resources in national parks exist only to the extent thatthey exist for normal operations in managed forests.

In the Madrid region, within the Regional Park fragmentation and barriers due to theincreasing development of infrastructures (i.e. motorway N-VI west side of the park) do notpermit us to be very optimistic about the implementation of areas such as corridors orbuffer zones in this part of the territory.


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Annex 1

Basic Reports on ETC/NC project MN2.7, Ecological Corridors and Buffer Zones:

English Nature, Peterborough, England:Felton, M. 1995. Corridors and buffer areas: requirements of the Habitats and SpeciesDirective and the Birds Directive. Preliminary Report, Project MN2.7, ECNC, ETC/NC

Staring Centrum, Instituut voor Onderzoek van het Landelijk Gebied, Wageningen, TheNetherlands:Farjon, J.M.J. and J.B. Bakker. 1995. Ecological corridors and buffer zones: Role,practical experience and planning. Preliminary Report, Project MN2.7, ECNC,ETC/NC.

UNESCO Chair for Ecological Awareness and Sustainable Development, Banska Stiavnica - TUZvolen, Slovakia:Miklos L, M. Koren and J. Steffek. 1995. Ecological corridors and buffer zones.Preliminary Report, Project MN2.7, ECNC, ETC/NC.

Centro de Investigacion de Espacios Naturales Protegidos, DepartamentoInteruniversitario de Ecologia, Comunidad de Madrid, Spain:Mugica, M., J.V. De Lucio and F.D. Pineda. Ecological corridors and buffer zones: Thestudy case of Madrid region, Spain. Preliminary Report, Project MN2.7, ECNC,ETC/NC.

Biodiversity Conservation Laboratory, Department of Environmental Studies,University of the Aegean, Lesbos, Greece:Troumbis, A.Y. and N. Kardakari. 1995. Ecological corridors and buffer zones inGreece, Italy and France. Preliminary Report, Project MN2.7, ECNC, ETC/NC.


Annex 2

PARTICIPANTS ON THE MEETING OF THE ETC-PROJECT MN 2.7, BUFFERZONES ANDCORRIDORS

Teresa AndresenUniversidade de Aveiro, 3810 Aveiro, Portugal

Carles CastellServei de Parcs Naturals de BarcelonaCompte d’Urgell 187, 08036 Barcelona, España

Ricardo ColmenaresCIFGB, San Sebastian, 7128791 Soto del Real, Madrid, España

Juan Manuel de BenitoEuropean Topic Centre on Nature ConservationMNHN, 57 Rue Cuvier, 75231 Paris Cedex 05 Paris, France

Geert Den BlustInstitute for Nature Conservation VlaanderenKiewitdreef 5, 3500 Hasselt, Belgium

Francisco Diaz PinedaComplutense University, Dept Ecología28040 Madrid, Spain

Hans FarjonWinand Staring CentrePO box 125, 6700 AC Wageningen, The Netherlands

Mark FeltonEnglish Nature, PeterboroughPE1 1UA England

Rainer JähnigBundesamt für NaturschutzKonstantinstraße 110, 53179 Bonn, Germany

Rob JongmanWAU-Dept of physical planning and rural developmentgen Foulkesweg 13, 6703 BJ Wageningen, The NetherlandsandECNC, Postbox1352, 5004 BJ Tilburg, The Netherlands

Dr Renato MassaUniversity of Milan. Dept of Environmental ScienceVia L. Emmanueli 15, 20126 Milan, Italia


Ladislav MiklosInstitute for Landscape Ecology, Academy for SciencesPO-box 254 (Stefanikova 3), 814 99 Bratislava, Slovakia

Marta MugicaCIFGB, San Sebastian, 7128791 Soto del Real, Madrid, España

Ole OstermannEuropean Topic Centre on Nature ConservationMNHN, 57 Rue Cuvier, 75231 Paris Cedex 05 Paris, France

Ulla PinborgEuropean Environmental AgencyKongens Nytorf 6, DK 1050 Copenhagen, Denmark

Karl ReiterInstitute of plant physiology of the University of ViennaDepartment of Vegetation Ecology and Conservation BiologyAlthanstraße 14, Box 285, A 1091 Vienna, Austria

Alain TamisierCentre d’Ecologie Fonctionelle et Evolutive CNRS MontpellierEquipe de Recherche sur les Oiseaux des Eaux MéditerranéensLe Sambuc, 13200 Arles, France

Andreas TroumbisDept of Environmental Studies, University of the Aegean17 Karantonistreet, GR 81 100 Mytilene, Greece

José Vicente de LucioCIFGB, San Sebastian, 7128791 Soto del Real, Madrid, España

Dirk WascherECNC, postbox 1352, 5004 BJ Tilburg, The Netherlands

Thomas WrbkaInstitute of plant physiology of the University of ViennaDepartment of Vegetation Ecology and Conservation BiologyAlthanstraße 14, Box 285, A-1091 Vienna Austria

Written comments have been received from:

Françoise Burel,CNRS URA 696, Université de Rennes 1Laboratoire d'Evolution des systèmes naturels et modifiésCampus de Beaulieu, 35042 Rennes Cedex, France