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Proceedings of the 2013 International Conference on Ecology and Transportation (ICOET 2013)
BEST PRACTICES FOR IMPLEMENTING BIOTOPE NETWORKS IN
HIGHLY FRAGMENTED LANDSCAPES:
THE SAFETY NET FOR THE EUROPEAN WILDCAT
Burkhard Vogel, Ph.D. (++49 361 555 03 12, [email protected]), Managing
Director, BUND Thuringia, [email protected]
Thomas Mölich (++49 36254 85962, [email protected]), Project Manager. BUND
Thuringia, [email protected]
ABSTRACT
The fragmentation of landscapes belongs to the major causes for the ongoing loss of
biodiversity worldwide. Remaining habitats have become isolated patches within intensively
used cultural landscapes for many species. One of those species is the European wildcat Felis
silvestris silvestris SCHR. The original range of the European wildcat once covered forests
allover central and southern Europe. Today, wildcat distribution is heavily scattered due to
former human persecution and habitat fragmentation in Europe and especially in Germany.
To counteract this process, the environmental NGO BUND (Friends of the Earth Germany)
initiated a comprehensive project on biotope networking called “The Safety Net for the
European Wildcat” in 2004. The ambitious aim of the project is to establish a continuous
forest network of 20,000 kilometers length. Scientific basis of the project is the wildcat
routing map. It was calculated by combining the outcomes of a comprehensive habitat model
with a cost-distance-analysis in order to identify optimal connection routes between forests
occupied by wildcats and suitable wildcat habitats. Result of this procedure is a map which
shows potential migration corridors between all relevant forests throughout Germany.
Although the wildcat is the target species of the initiative, many other species benefit, thereby
improving the health of entire forest ecosystems.
The implementation of this corridor implicates a high potential for conflicts with land-use
owners due to the high competition for land by further infrastructural development,
agriculture and nature conservation. In order to raise public awareness and gain support for
biotope networking the BUND ran an accompanying publicity campaign from 2010 to 2012.
Stakeholder dialogues and public relations were major parts of the campaign, which was
funded by the EU (LIFE+). The case example of the first corridor implemented in the
framework of the wildcat project shows how potential conflicts can be dissolved: This
corridor was planted in 2007 in order to reconnect the Hainich National Park, which is
inhabited by a stable wildcat population, with the Thuringian Forest, where wildcats are still
rare. Intensively used agricultural land and a highway are major barriers for wildlife
migration between the two forests. When this highway was relocated the chance arose to
implement a wildcat corridor in the area. As a result of a long-lasting, but successful process
of dialogue between authorities, local farmers and the BUND compensational measures were
bundled within an area suitable for a wildcat corridor. Already in 2012 the first wildcats were
proven to use the corridor. Two other corridors in Rhineland-Palatinate and Lower Saxony
followed.
With funding from the German federal administration BUND will implement six new wildcat
corridors within the next two years in order to push forward the establishment of a functional
network of forests. Furthermore, an open database with wildcat DNA samples from ten
Vogel and Mölich 2
monitoring regions throughout Germany will be established. Since the reconnection of
European forests is a truly international task, BUND has a strong interest in initiating
international collaborations for biotope networking for the long term.
INTRODUCTION
Landscape fragmentation is one of the main causes for the continued loss of biological
diversity in central Europe. In the densely populated industrial country of Germany the
unchecked increase of urban and industrial areas, the expansion of traffic infrastructure and
the intensification of agriculture and forestry are reasons for ever fewer available large,
unfragmented natural areas. Especially affected by this process are forest habitats. Forests are
part of the original landscapes of Europe and after the last ice age used to cover vast parts of
the continent. Today, only 1/3 of Germany is covered by forest. Pristine forests, without
major fragmentation, with more than 100 km2 area, do not exist anymore. For many forest
species the existing forests are turning into habitat islands, in a cultural landscape that is
being used ever more intensely. For forest species like badger (Roth et al. 2000) or lynx
(Schadt et al. 2000), as well as many birds, the negative impacts of fragmentation have been
proven (Brotons & Herrando 2001).
Prominent example for this process is the wildcat: 150 years ago wildcats were widespread in
the forests of Germany. Since then, the population has decreased continuously. Today,
wildcats live reclusively in populations that in some cases are strongly isolated from each
other (Pierpaoli 2003).
Biotope concepts that counteract the consequences of fragmentation through the reconnection
of habitats have been under discussion for a long time in Germany (Jedicke 1994). The
functionality of such corridors has been proven by a number of studies (Beier 1993).
Intelligently laid out corridors help to interlink isolated forest biotopes (Bennett 1990, Perault
& Lomolino 2000, Brotons & Herrando 2001, Opdam 1991).
Since 2002 the German Environmental Act obligates the German States to create a
nationwide biotope network on 10 % of its land area (BNATSCHG 2002, § 3, ABS. 1).
Nonetheless, thus far the implementation of biotope network concepts is usually only
happening at small- and medium scale level. Within the scope of the implementation of the
European Protection Network Natura 2000, only isolated habitats have been reported and the
designation of network corridors has been refrained from.
Schemes for the large-scale reconnection of habitats at national or state level do not exist in
Germany thus far. Forest ecosystems play an essential role in the creation of a nationwide
biotope networks. Forest species react to landscape fragmentation more sensitively than
species of the open country.
With the project “A Safety Net for the Wildcat" the BUND has made the reconnection of
forest habitats in Germany its goal. The implementation of this goal is to be achieved by
means of:
- The establishment of a „Wildcat Routing Map“ as a strategic instrument for the
nationwide network plan
- Model-like implementation of corridors in well-chosen key locations
- The verification of the effectiveness of corridors by means of genetical analysis
Vogel and Mölich 3
- Nationwide genetical screening and setup of a genetic database for the
characterization of the population structure and the migration movements of the
wildcat in Germany
MATERIAL AND METHODS
The Wildcat Routing Map
The modeling of the migration paths of the wildcat as it relates to Germany. The data for its
land use are derived from the CORINE Project. Vector data from Germany from the year
2000 and grid data with the resolution of 250 m of the neighboring countries was used. The
applied scale is 1:100,000.
For the modeling of the wildcat corridors, cost-distance analysis were used (see Adriaensen et
al. 2003, Kautz et al. 2006, Schadt et al. 2002). In order to determine the resistance values in
landscape, a statistical habitat model for the wildcat was applied (Klar et al. 2008). Basis for
this model was radio-telemetric research on the wildcat. The resulting habitat applicability
values were used directly as resistance values for the cost-distance-analysis. In that context,
forest was assigned a low and agricultural landscape a high resistance value.
On the second step 35 starting points and 52 finish points were chosen. Starting points were
chosen, so that each established wildcat population in Germany was represented by a starting
point. Additionally, starting points were placed at the borders to other countries that are
known to have wildcat populations, which means areas from which wildcats could emigrate.
The location of the finish points was chosen with the help of the habitat model. The points
were placed in the areas that are categorized as suitable for wildcats, but where no proof of
stable populations exists yet. Only areas larger than 500 km2 were selected. Additionally,
finish points were placed at the borders to neighboring countries, where connections to
bordering forest habitats that are suitable for the wildcat are possible.
Genetical Evidence that corridors are being used by the wildcat
Wooden stakes (100x5x5 cm equals 39.4 x 1.9 x 1.9 inches) treated with valerian root extract
(Valeriana officinalis) are used to collect hair samples from wildcats. Valerian works as a
good olfactory attractant for cats. While exploring the stakes, the cats leave varying amounts
of hair on the rough sawn surface. These hair samples are collected from January to April, in
the mating period of the wild cats, generally once a week. Hairs are tweezed and stored in a
locking plastic bag containing drying paper on silica gel to minimize DNA – degradation.
DNA extraction and genetical analysis is done at Forschungsinstitut Senckenberg,
Gelnhausen, Germany.
Genetical Analysis
The genetical analysis of hair samples comprises sequence analysis of mitochondrial DNA as
well as nuclear DNA analysis with one sex marker (Pilgrim et al. 2005) and 14 microsatellite
markers (Menotti-Raymond et al. 1999). For details see Steyer et al. (2012).
Vogel and Mölich 4
Gene-Screening
Wildcats are genetically screened on a nationwide scale to characterize different populations
and reveal effects of isolation and hybridisation on a finer scale than presently known
(Pierpaoli et al. 2003; Krüger et al. 2009).
Figure 1 shows the location of 16 sampling rasters in known wildcat habitats in Germany,
each consisting of 25 adjacent cells of 3 km edge length.
FIGURE 1 Location of 16 sampling rasters in known wildcat habitats in Germany
Each cell contains two lure stakes placed in forested areas. The rasters are usually checked
weekly as described above in the winter season from 2011/12 to 2014/15. The work is done
by more than 400 volunteers (most of them members of BUND, hunters, foresters) who
received a special training concerning the lure stake method by BUND Wildcat Bureau.
Vogel and Mölich 5
FIGURE 2 The sampling raster “Hainich” as an example. Numbered dots: locations of
lure stakes. Green Line: border of National Park Hainich
Vogel and Mölich 6
RESULTS
Current and Potential Wildcat Habitats
FIGURE 3 Current distribution of the wildcat in Germany from the “Action Plan for
the Protection of the European Wildcat (Felis silvestris silvestris SCHREBER 1775) in
Germany“ (Birlenbach & Klar 2009).1-11: Populations. 12-19: Single Evidence. a-c:
reintroduction projects in the past.
Clearly visible is the spatial division between the wildcat distribution in West-Germany and
in Middle-Germany.
In figure 4 the start and end destination areas are depicted, from which the most convenient
path connections were calculated. The figure emphasizes the large potential of suitable
wildcat habitats within all German states.
Vogel and Mölich 7
FIGURE 4 Current and potential wildcat habitats in Germany with start-destination
points for the modeling of corridors.
Vogel and Mölich 8
The Wildcat Routing Map for Germany
FIGURE 5 Wildcat Corridors for Germany (for map and Web-Mapping see
www.wildkatze.info)
Vogel and Mölich 9
In the German-wide Wildcat Routing Map the corridors connect current wildcat distribution
areas with each other, as well as the existing populations with potential distribution areas
(Figure 3). The potential wildcat areas without an actual wildcat distribution are not
necessarily connected with each other. Taken together, all the corridors of the Wildcat
Routing Map, including existing forested areas, have a total length of 20,000 km. In
comparison: the German road network encompasses 12,400 km federal highways and 41,000
km state highways.
Model corridor Hainich – Thuringian Forest
The practicability of the Wildcat Routing Map is shown by the model corridor „Hainich –
Thuringian Forest“. The Hainich is the largest, continuous deciduous forest area in Germany.
The entire forest area is inhabited by wildcats.
The Thuringian Forest is a mixed forest, consisting of deciduous and coniferous trees. It is
located in southerly direction, not even 20 km distance to the National Park Hainich and
offers a large range of suitable habitats. Nonetheless, there was no evidence for the existence
of established wildcat populations in the past decades. The path to it from the Hainich has
been a dead-end, as field research shows (Mölich & Klaus 2003). The federal highway A4
Eisenach-Erfurt and the cleared and intensively used agricultural landscape act as barriers and
prevent migration of wildcats (and certainly many other species) from Hainich to Thuringian
Forest.
Since a rerouting of the federal highway A4 occurred due to transport engineering reasons,
the chance to create a biotope connection between Hainich and Thuringian Forest arose.
During construction of the new highway, a large valley bridge had to be built, under which
wildcats can now cross the highway unimpeded.
For the associated landscape destruction of the new highway, compensational measures were
determined. Those were bundled in a way, so that a 50m wide and 1.2 km long strip of forest
was planted. It closes the gap between the existing biotope network structures. Hence, the
first part of the spatial network between Hainich and Thuringian Forest, from Hainich to
Hörselberge, was established for migrating species.
Vogel and Mölich 10
FIGURE 6 The corridor between the National Park Hainich and the Nature Park
Thuringian Forest. 1 National Park Hainich. 2 Biotope network structures. 3 Open
fields. 4 Hörselberge. 5 Biotope network structures on the southern edge of the
Hörselberge. 6 Thuringian Forest.
Use of the Corridor Hainich – Thuringian Forest
Since 2010, the presence of wildcats inside the planted corridor and its neighboring open
fields is logged with the help of the lure – stake method. Stakes are checked for hair samples
once a week from beginning January to end of April. No wildcats could be detected 2010 and
2011. In 2012, the 5th year after the vegetation corridor was planted, first samples turned out
to be hair of wildcat. More positive samples occurred in 2013 but not all of this year’s
samples have been analysed yet.
Vogel and Mölich 11
FIGURE 7 The picture shows lure stakes (numbered green and red squares) along
the vegetation corridor (green belt). Lure stakes where wildcats were detected are
marked red. Aerial photo: Freistaat Thüringen, Landesamt für Vermessung und
Geoinformation, Erfurt.
A female wildcat was detected at two different spots inside the corridor as well as at the foot
of the Hörselberge hills (red squares). Three more individuals were logged close by in older
vegetation structures (not shown in the figure).
Vogel and Mölich 12
TABLE 1 List of Wildcat detections along the corridor connecting National Park
Hainich with the “Hörselberge”. f=female, ?=sex or individual not determinable,
“F”=Code for identified individual. The total number of collected samples was 18.
Analysis of 5 samples is still in progress.
ID of Stick visited by
Wildcat
Sex Individual Sample
collected
- 2010
- 2011
16 ? ? 1/26/2012
17 f „F“ 3/1/2012
4 ? ? 3/17/2012
17 f „F“ 3/17/2012
13 f „F“ 2/6/2013
13 f „F“ 2/15/2013
Gene-Screening
In the first year (winter 2012) a total of 1169 hair samples was collected. Up to now, 615
samples were analyzed. 282 wildcat samples are presently identified (142 individuals, 86
males, 55 females). From winter to spring 2013 436 samples have yet reached the
Senckenberg Institute and will be analyzed in the next months.
CONCLUSIONS
Do the corridors work?
A number of telemetric studies attest, that the occurrence of wildcats is closely linked to the
existence of forest habitat. Intensively used, open agricultural landscape is shunned by
wildcats, in contrary to their close relatives, house cats. Thus far, there has not been direct
proof, that wildcats use corridors, in order to wander between forest habitats. The results of
the gene-monitoring along the model corridor „Hainich-Thuringian Forest“ show
nonetheless, that wildcats are using the corridor that was put in place a few years ago.
Currently, the habitat structure still corresponds with that of grassland with young trees. A
forest habitat has not yet developed along the corridor. Nonetheless, wildcats prefer the
corridor over the surrounding agricultural landscape. It is likely, that the corridor offers more
food in the form of mice. Furthermore, bushes and old grass stands provide cover for the cats.
Thus, the corridor improves the network between the adjoining forest areas.
Whether this also increases the permeability of the landscape for the wildcat and furthers the
resettlement of habitats cannot be answered conclusively at this point.
In order to answer those questions, the BUND is setting up the first German-wide gene
database for wildcats in the course of its project „Wildcat Leap“. A comparable,
comprehensive genetic assessment of a wild mammal species in Germany has not been
undertaken thus far.
This wildcat-inventory makes it possible to assess, whether and to what extent, an exchange
between the wildcats in the isolated forests of Germany is occurring. In addition, wildcat
migrations of individuals can be monitored. This information will flow into the work dealing
Vogel and Mölich 13
with the Wildcat Routing Map. In this way, the BUND can determine the most important
corridor regions (vgl. Beier & Gregory 2012).
Moreover, the data permits statements about the genetic diversity of the gene pool of the
wildcats. Genetic diversity is one of the three pillars of biological diversity. The construction
of a gene database for the wildcat is therefore an essential next step for the long-term
protection of the species wildcat and Germany’s biodiversity.
Is the Wildcat Routing Map viable?
A forest network of 20,000 km appears to be an utopian order of magnitude. However, based
on the forest area of the Federal Republic of Germany, the number is relative. Assuming an
average corridor width of 50 m, a total area requirement of 1.000square km ensues. In
comparison: Germany has a total area of 358,000 square km and its forest area encompasses
110,400 square km. Thus, the Forest Network Plan only takes up 0.3% percent of Germany’s
area, which equals 0.9% percent of Germany’s forest area. In comparison: in Germany it
takes less than three years for an area that size to be completely sealed.
It has to be taken into account as well, that the corridor network does not have to be created
from scratch. In the case of the cost-distance-analysis, the calculated connection axes orient
themselves on already existing structural elements in the landscape. Thus, in many cases a
continuous network between existing habitats can be achieved by simply closing gaps.
The financial feasibility of the here proposed nation-wide network is given: the necessary
financial resources are low compared to the investments undertaken in road infrastructure.
For the construction of a corridor of one kilometer length and ca. 50 m width, including the
purchase of land and complete planting of vegetation, a total investment sum of ca. 300,000.-
Euro can be appraised. The average cost for a kilometer of highway is 12 Mio. Euro, which is
40 times the amount. The realization of the nation-wide Wildcat Routing Map within 10
years therefore is a realistic prospect.
The Wildcat Routing Map, as a strategic instrument of nature protection planning in
Germany
The Wildcat Routing Map concentrates on the wildcat. However, it is not merely a species
conservation concept. The Wildcat Routing Map is a strategic instrument to reconnect forest
habitats in Germany (see Vogel et al. 2009). The wildcat was chosen as a target species. To
secure the survival of this species German-wide, a strategic goal, the interlinking of forest
habitats suitable for the wildcat, larger than 500 km2, is defined. The scope of the interlinking
of forest habitats that is necessary to reach this goal was assessed using scientific methods. In
the end, not only the wildcat benefits, but all species that depend on a functioning forest
network.
The interactive map of the Wildcat Routing Map is available online under
www.wildkatze.info. Hence, a comparison of state planning and Wildcat Routing Map at all
planning levels, for all locations in Germany, is possible at any time. Prior to large scale
projects, that entail major fragmentation of the landscape, exclusion areas can be identified
and suggestions for the most landscape compatible alternative can be derived.
Vogel and Mölich 14
Ultimately, the wildcat as popular figure, creates the prerequisite for the political
assertiveness of the proposed measures. Measures for the protection of the wildcat achieve
high acceptance among the population and the political decision makers.
ACKNOWLEDGEMENTS
The authors thank the active people in administration, business and institutions, as well as the
full-time and voluntary employees in the „Safety Net Wildcat“ for their dedication. A special
thanks goes to the Federal Environmental Ministry, which accompanies the „Wildcat Leap“
project by means of the “Federal Program for Biodiversity” and the Federal Agency for
Nature Protection, which accompanies the project professionally, as authorization agency.
BIOGRAPHICAL SKETCHES
Burkhard Vogel studied Biology at the Universities of Saarbruecken and Wuerzburg,
Germany. After completing his diploma studies he was postgraduate at the Helmholtz Center
for Environmental Research. Following he worked as scientific assistant at the Center for
Nature Conservation (CNC) on the University of Goettingen. He did his PhD at the
University of Wuerzburg focusing on population ecology. Since 1999 Burkhard Vogel is
managing director at the environmental association BUND in the federal state Thuringia. He
is responsible for the environmental and nature conservation policy of the BUND in
Thuringia as well as the projects of the NGO.
Thomas Mölich studied Biology at the Universities of Mainz and Göttingen. After
completing his diploma studies he managed the first field study on native wildcats in
Germany for the environmental association BUND. For the Federal State of Thuringia he
took part in establishing National Park Hainich from 2000 to 2003. Since 2004 Thomas
Mölich is funding and managing nature conservation projects with the wildcat as a target
species for the BUND. His focus is on the realisation of biotope networks in dialogue with
science and stakeholders.
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