The assessmenT of landscape and vegeTaTion …31 The assessmenT of landscape... The assessmenT of landscape and vegeTaTion chang-es: The case sTudy – upper lusaTian heaTh and pond

31The assessmenT of landscape...

The assessmenT of landscape and vegeTaTion chang-es:

The case sTudy – upper lusaTian heaTh and pond landscape

olaf Bastian

saxon academy of sciences, dresden, germany

abstract

In the UNESCO-biosphere reserve „Upper Lusatian heath and pond landscape” (301 km2), a complex landscape-ecological research programme including studies of landscape changes and threats was realized. Especially, the following analyses are described:– changes of land use and secondary landscape structure, compared with the aid of

maps at four times;– ecological situation of the river Kleine Spree: morphology, water balance, water

chemistry, and vegetation;– present vegetation within and around the fish-ponds and its bioindicative value;– present grassland vegetation (riverside meadows): vegetation units and bioindi-cation

of site conditions;– comparison of vegetation of moist forests (fenwoods and oak-hornbeam forests):

vegetation relevés in 1950s to 1990s; – changes of soil properties (comparison of past and present situation);– construction of the potential natural vegetation at two times: historical and present

potential natural vegetation;– landscape functioning in its changeability.Consequences for the future landscape development are outlined.

introduction

Structure, function and change are among the most important points of view in modern, holistic landscape-ecological research and planning. Thus, it is necessary to compare historical and present situation in order to grasp landscape changes and to favour a more dynamical view. Investigations of landscape change, above all, have several objectives (Bastian, 1991): • Early recognition and assessment of development tendencies give the possibility of

intervening in a regulating manner and countering efficiently possible undesired processes in due time and thus at relativly low economic expense.

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• Knowledge and documentation of the ecological situation of passed ages are absolutely part of the preservation of our historical and cultural heritage.

Schulz (1998) expects a „historical landscape analysis“, starting-points for the characterization of landscape’s peculiarities and its current ecological situation (including various landscape factors like soil, water, climate, land use), and for the elaboration of landscape visions „without breaks” with the previous development. Landscape change is a complex process, comprehending physical, biotic and human factors. Recent studies of landscape changes cover an essential part of all activities in landscape-ecological research. For example, 78 of 524 presentations (= 15%) of the 5th IALE world congress (29.7-3.8.1999, Snowmasse Village, USA) dealt with this issue, 21 (= 27%) of all change studies (78) with vegetation changes, 31 (= 40%) with land use / land cover changes. The practicability of such studies stands the test or not with the availability of (esp. historical) data that differs with parameters and geographical location. At best, there are series of topographical maps, whereas information concerning soils, waters, vegetation, fauna, and special land use regimes is scaree. With regard to the sustainable use and to landscape management programmes in biosphere reserves, studies of human induced landscape changes are of particular importance. Approaches and results of such investigations are shown on the example of the biosphere reserve – Upper Lusatian heath and pond landscape.

study area

Biosphere reserves are a category of protected areas which were introduced in 1973 in the frame of the UNESCO MAB-programme. In 1974, the following objectives were outlined by the FAO (Food and Agricultural Organization of the United Nations):• to conserve the diversity and integrity of biotic plants and animals communities

within natural and semi-natural ecosystems, including those maintained under long-established land use,

• to provide areas for ecological and environmental research;• to provide facilities for education and training. Biosphere reserves contain characteristic ecosystems of the earth, and they shall realize aspects of nature preservation, management of valuable cultural landscapes according to a holistic approach and link economy, ecology, culture, and ethics of the people (see Fig. 1-4). They represent a network for monitoring environmental changes. The Upper Lusatian biosphere reserve which was founded only recently is one of 13 in Germany and of more than 340 in the world. The reserve (301 km2) contains a representative part of one of the largest Central European fish-pond areas. There are a lot of rare plant and animal species and a high diversity of valuable biotopes, e. g. dry and moist forests, swamps, heaths, dry and wet meadows, reeds, waters. Most remarkable about the fauna is that this area has the largest number of old world otters (Lutra lutra) in Germany 15 species of bat, and 150 breeding bird varieties (e. g. the white stork - Ciconia ciconia). Typical of its ponds and wetlands is that significant parts of the Saxon populations of sea eagles (Haliaeetus albicilla - 40%), cranes (Grus grus - 30%), red-neck grebes (Podiceps grisegena - 30%), and goldeneyes (Bucephala clangula - 40%) live there. In addition, most of the protected indigenous amphibians


Fig. 2. An old water-mill at the Spree river near Halbendorf village. In front a sandy rough meadow with flowering Hieracium pilosella and Rumex acetosella.

Fig. 1. Extensive Calluna-heaths have developed especially on former military training areas.

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Fig. 3. Old road marks belong to our cultural heritage.

Fig. 4. Local marketing of goat products is also an attraction for tourists.


and reptiles are found in this area, e. g. the fire-bellied toad (Bombina bombina) and the tree frog (Hyla arborea). Remarkable invertebrates live in sandy dunes, such as yellow-jacket, digger and sand-wasps, dune antlions and robber wasp. Usually, biosphere reserves are divided into four protection zones (see Tab. I).From its establishment in 1994, our working group of the Saxon Academy of Sciences carries out scientific activities to deepen several aspects of landscape-ecological research (Syrbe et al., 1998; Bastian, 1999; Röder, this issue) and accompanies - at the same time - the administration by underpinning their efforts. Several degree dissertations have also served this objective (Schulze, 1997; Arnold, 1998; Großert, 1999; Hoffmann, 1999; Martin, 1999), caused and supervised by us. We are working on two levels (scales) and with specific indicators/metho-dologies:– regionally (1:50,000) to gain a general view of the total area of the biosphere

reserve,– locally (1:10,000) to enable precise and comprehensive research in two smaller test

areas:1. The floodplain of the „Kleine Spree” small river (16.1 km2) mainly belongs to protection zone II: Apart from some riparian woods, alder swamps and fish-ponds, arable fields, grassland and small settlements dominate (see Fig. 5).2. The agricultural area east of the Kreba village (5.8 km2, zone IV): Large arable fields predominate, only very few meadows and woods structurize the landscape. Negative consequences are deflation on sandy soils, and the reduction of biodiversity.

Fig. 5. Kleine Spree river in the harmonious cultural landscape of the Lusatian biosphere reserve.

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The main tasks of our research programme are the analysis and the assessment of • landscape structure, including physical and biological parameters, as well as attri-

butes of land use,• landscape functions, and• landscape changes as a basis of landscape prognosis and monitoring (Syrbe et al.,

1998).

Land use changes in the Kleine Spree floodplain

Usually, land cover meets a fundamental attention in studies of landscape changes. For the Kleine Spree floodplain, selected land use types (forests, grassland, arable

Table i. protection zones in the biosphere reserve „upper lusatian heath and pond landscape”

protection characteristics aim size / ecosystems zone share

II-Buffer zone

Valuable biotopes which most ly are the result of human cultivation

M a i n t e n a n c e a n d caring utilisation serve the interests of nature exclusively and are caried out in accordance with precisely defined plans.

12.015 ha (= 39.9%)

Ecologically-important pond areas and their adjacent woods and grasslands, floodplain and wet meadows, heaths

I - Core area The o r ig ina l state with natural ecosystems is maintained to a large extent

All natural processes are to be allowed, without human intervention and influence

1.024 ha (= 3.4%)

Marshes, inland dunes, riverside forests

III - Transition zone

Most intensively used areas with less ecological values

Regular agriculture, forestry and fishery are possible, while preserving or improving the natural scenery, prevent water pollution and erosion. The villages shall be developed while keeping the surrounding scenery

14.949 ha (= 49.7%)

All the other areas, which are used for agriculture, fishery or forestry, settlements

IV - Regenera-tion zone

Areas where the balance of nature is harmed es-sentially

After regeneration these areas shall be included in higher categories

2.014 ha (= 6.7%)

Areas which suffer from groundwater lowering (influences of brown-coal mining, ruthless hydromelioration), very intensive agriculture, carries, kaolin pits


fields, settlements), and landscape elements (standing and running waters, paths and roads, single trees, groups of trees, woodlots and hedgerows, and the borders between different land use types) were analyzed for four periods (time points: 1825 - 1884/86 - 1936 - 1987/91) with the aid of topographical maps 1:25,000 and digitalized (Schulze, 1997; Fig. 6). Quantitative analyses explained that this rather natural land-scape is subjected to essential human impacts and landscape changes, too. The developments

Fig. 6. Land use changes in a part of the Kleine Spree floodplain (from Schulze, 1997).

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Table iii. Boundaries (m /%) between land-use types and linear landscape elements in the Kleine Spree floodplain (from Schulze, 1997)

Boundaries 1825 1884/96 1936 1987/92 (= 100%)

Forest/grassland 19,550 14,520 (74 %) 18,890 (97 %) 15,390 (79 %) Forest/arable fields 6,630 3,560 (54 %) 3,590 (54 %) 5,370 (81 %) Grassland/arable fields 30,390 28,890 (95 %) 30,300 (99 %) 9,090 (30 %) Edges of settlements 7,480 7,720 (103 %) 10,220 (137 %) 10,830 (145 %) Banks of ponds 25,920 3,640 (140 %) 33,130 (128 %) 35,850 (138 %) Running waters (km), 36/15 29/21 20/42 7/45 category A/B* (81%/140%) (56%/280%) (19%/300%)

*Category A – natural or only slightly impacted; category B – impacted to far from nature (see Tab.

Table IV. Average size of arable fields and grasslands in the Kleine Spree floodplain (from Schulze, 1997)

Table II. Land use changes in the Kleine Spree floodplain (ha/%)(from Schulze, 1997)

(Only c. 2/3 of the test area were considered because no maps were available for the former Prussian part in 1825)

1825 (100 %) 1884/86 1936 1987/92 Arable fields 2.5 ha 2.3 ha (92 %) 1.9 ha (76 %) 14.0 ha (560 %) Grassland 3.6 ha 4.0 ha (111 %) 3.2 ha (89 %) 4.3 ha (119 %)

Phases (time points): 1. 2. 3. 4 1825 (100 %) 1884/1896 1936 (1987/1992) Forests/fenwoods/coppices 76/?/8 (S 84) 31/10/32 (87 %) 84/?/24 (129 %) 81/19/20 (143 %) Grassland/moist grassland 354/88 (S 442) 374/64 (90 %) 431/19 (102 %) 265/59 (73 %) Arable fields 237 227 (96 %) 181 (76 %) 307 (130 %) Settlements: buildings/ 21/8 (S 29) 25/8 (114 %) 27/10 (128 %) 38/7 (155 %) gardens and open spaces Standing waters (ponds) 188 ha 208 (111%) 201 (107 %) 170 (90 %)


follow general trends of landscape changes in Central Europe described by Bastian and Bernhardt (1993), and others. Extent and rate of changes increased more and more, and the most important differences could be established between the last two phases (1936 - 1987/91). The intensification of agriculture is regarded as the main cause. All land use types and most of the landscape elements are concerned (Tab. II). Generally, size of individual areas increased, and the number of landscape elements, edges (ecotones),

Fig. 7. Changes in the system of running waters in a part of the Kleine Spree floodplain (from Schulze, 1997).

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and therefore landscape heterogeneity decreased (see Tab. III, IV). The comparison of topographical maps, however, conveys only an incomplete picture of landscape changes. Even if no obvious changes could be established, the consequences of higher land use intensities (e. g. application of fertilizers, biocides, irrigation, drainage, reduction of crop diversity - vanishing flax, millet, buckwheat; soil compaction, surface sealing) must not be ignored. Furthermore, apart from subjective aspects of mappers, there had been different mapping instructions for the map series (e. g. for the registration of linear woods, borders beween elements like swamps, reeds, wet and fresh grassland). Special attention was given to the running waters themselves (Kleine Spree river, tributary rivulets and ditches). With a special method (according to Giessübel, 1993, modified for topographical maps), the naturalness of waters morphology was assessed (2 degrees, Tab. V). Step by step, a decrease in „natural and only slightly impacted“ sectors (of running waters) took place 1825: 71% —> 1884/86: 58.5% —> 1936: 33% —> 1987/92: 16%). Morphological changes are: straightening and canalization (reclaimation), construction of weirs, creation or removal of ditches and riparian woods (Schulze, 1997). Today, Kleine Spree over long distances represents a channel-like streamlet with an artificial morphology: with technical (stony) embankments, small barrages, deepened bottom, missing riparian woods and other typical habitats (see Fig. 7, 8). Water quality is impacted by nutrients from liquid manure (cattle breeding), sewage, outlets from fish-ponds, non-point source runoff from arable fields and pastures (Martin, 1999).

Fig. 8. Over long distances Kleine Spree river was reclaimed: here with Glyceria maxima-reeds.


Bioindication of threats and changes

Waters In contrast to historical topographical maps, comparable comprehensive basic materials concerning biological features of a landscape mostly do not exist. A resort is the interpretation of present data (e. g. vegetation relevés) with the aid of available historical data (topographical maps, older publications, documentations in archives or museums) or with experiences from other test areas. Our investigation included analysis and mapping of vegetation units of running and standing waters, grasslands, forests and arable fields, the calculation of ecological indicator values, and the inter-pretation of these data concerning actual ecological conditions, impacts and changes. In order to return to Kleine Spree river, we could establish, that morphological and chemical conditions and the way of utilization adjacent stripes are well reflected by the riverside vegetation: nitrophilic reeds being poor in species (e. g. Phalaridetum arundinaceae with nitrophytes) and perennial herb communities (esp. with the stinging nettle Urtica dioica)(Martin, 1999). A phytosociological analysis (Arnold, 1998) of a group of fish-ponds showed the dominance of nitrophilic communities, too (see Tab. VI, Fig. 9). For example Lemno-Spirodeletum covers areas sheltered from the wind. Potamogetonetum pectinati indicates heavily polluted ponds, and Zannichellietum palustris also prefers eutrophic waters. Reeds (Phragmitetum australis) lines (säumt) most of the ponds and adjacent ditches; nitrophytes such as Urtica dioica, Galium aparine, Calystegia sepium and Solanum dulcamara often are added. Also Glycerietum maximae indicates eutrophic conditions. As representatives of nitrophilic and ruderal edges, Urtico-Convolvuletum and Bidenti-Polygonetum hydropiperis, but also shrubs like Sambucus nigra - community dominate the pond banks. The dominance of nitrophytic plant communities is caused by water eutro-phication due to intensive fish farming. Whereas in 1946 only about 50 kg carps were produced per hectare, this number grew to 850 kg in 1969, and up to 1,500-3,000 kg by the end of the eighties. Intensification of fish farming (and agriculture) caused a

Table v. criteria for the morphological assessment of the running waters in the Kleine Spree- floodplain (from Schulze, 1997, sligthly modified)

parameter elements of natural elements of running waters running waters being far from nature

Structures (isolated, linear) curved course weirs, barrages, straightened course Riverside vegetation woods at one or at both sides no woods, but grassland, bank reinforcements Adjacent land use (of the forests, grassland arable fields, gardens, ways or floodplain) roads (parallel with the river), settlements (reaching to the water)

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Table VI. Vegetation types of a group of fish-ponds (near the village Lippitsch in the Kleine Spree floodplain) in the biosphere reserve

„upper lusatian heath and pond landscape” (according to data from Arnold, 1998)

plant community ecological characteristics occurrence in the test area open water areas Lemno-Spirodeletum polyrrhizae eutrophic waters shady areas sheltered from the wind Zannichellietum palustris eutrophic and polytrophic waters mostly as a broad stripe of the above sludge reeds Potamogetonetum pectinati heavily polluted, eutrophic and partly large patches polytrophic waters Potamogetonetum obtusifolii* mesotrophic waters here and there areas between open water and banks Typhetum angustifoliae mesotrophic up to polytrophic between open water area and the waters with muddy bottom adjoining Phragmites-reeds Phragmitetum australis a broad ecological amplitude,but shape almost all ponds and adjacent threatened by heavy water pollution ditches, interspersed with nitrophytes Glycerietum maximae eutrophic and polytrophic waters flat bank areas Sparganietum erecti* eutrophic waters places with frequent reed-cutting Acoretum calami muddy, eutrophic waters southern-exposed areas Rorippo-Oenanthetum aquaticae muddy, eutrophic waters frequently Sagittario-Sparganietum emersi muddy, eutrophic waters-banks stripes off Phragmites-reeds Caricetum ripariae* eutrophic peat-grounds Caricetum elatae* slight to medium eutrophic peats Banks of the ponds Peucedano-Calamagrostietum on sites of clear-cutted alder- upper banks of slightly shaded canescentis swamp-forests ponds Tanaceto vulgaris-Arrhenatheretum nutrient-rich sites only small fragments elatioris Lolietum perennis places with much trampling Potentilletum anserinae* typical for way- and ditch-sides Agrostis capillaris-Festuca ovina- piled banks of very sunny places community Lysimachio vulgaris-Holcetum moist edges moist, narrow banks of the ponds mollis Calamagrostis epigejos-community ruderal places edges of pond embankments Carex hirta-community edges of pond embankments Epilobio hirsuti-Convolvuletum sunny, warm pond embankments almost at all ponds and ditches sepium Urtica dioica-community almost at all ponds and ditches Bidenti-Polygonetum hydropiperis moist nutrient-rich muddy soils short-living Polygonum persicaria-community short-living, on building-rubble Rubetum idaei on clear-cuttings and fallowland shrubs at nearly all ponds, frequently in contact with forests, often dominated by Rubus fruticosus agg. Sambucus nigra-shrubs nitrophilic conditions surround adjacent forests (Urtico-)Salicetum cinereae interspersed nitrophytes indicate rather narrow at almost all ponds rich nutrient supply Rhus typhina-stands neophytic probably on places with old garden rubbish alder-/birch-/asp-woods/shrubs narrow stripes along banks of ponds Holco mollis-Quercetum prefers sites with better nutrient fragments, contact to adjacent larger conditions forests pine stocks (Pinus sylvestris) secondary forest stands variants with Deschampsia flexuosa and Molinia caerulea, contact to

* only small patches, rare.


serious decline of several bird species (e.g. waders, some ducks, rails and reedwar-blers) in this region, but also an increase of some other species, profiting from high fish populations and cereal feeding, e. g. Ardea cinerea, Podiceps cristatus, Fulica atra, Anas platyrhynchos, Aythya ferina, A. fuligula, Cygnus olor. The populations of some of these species nowadays declined again due to the decrease in the average fish yields (1998: only 615 kg/ha). grassland Grassland was analyzed very detailed in the floodplain of the „Kleine Spree” river (Tab. VII, Fig. 10-12). The most common community is the Alopecurus pratensis-meadow (Alopecuretum pratensis). Modern management practices caused an impove-rishment of the species spectrum. Moist forms can be identified with the occurrence of Phalaris arundinacea and Carex-species. Arrhenatherum elatius-meadow (Dauco-Arrhenatheretum elatioris) marks drier sites, but esp. species-rich forms became very rare. Fertile pastures (Cynosurion-communities) are mostly very poor in species, too. On sites with sufficient water supply (esp. on gleyic soils), moist and wet meadows are occurring, but mostly they are fragmented and reduced in species. We found e. g. Ranunculo-Deschampsietum, Epilobio-Juncetum effusi, Angelico-Scirpetum, but also Phragmites- and tall Carex-reeds. Moreover, Ranunculo-Alopecuretum geniculati and Rumex obtusifolius-occurrence indicate impacts by heavy cattle trampling.

Fig. 9. A large fish-pond near Kauppa village

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Table VII. Actual grassland and reed vegetation of Kleine Spree floodplain: communities, indicator values (according to Terra Botanica), and utilization

plant community w n o intensity

Molinio-Arrhenatheretea Arrhenatherion elatioris Dauco-Arrhenatheretum 3 3-4 3 i Alopecuretum pratensis, typical variant 3-4 4 (2-)3 i Alopecuretum pratensis, Aegopodium podagraria-variant 3-4 4 (2-)3 i Alopecuretum pratensis, Holcus lanatus-variant, typical variant 3-4 (3-)4 (2-)3 e Alopecuretum pratensis, Sanguisorba officinalis-variant 3-4 3-4 (2-)3 i Alopecuretum pratensis, Holcus lanatus-variant, moist variant 4 (3-)4 2-3 e Alopecuretum pratensis, Phalaris arundinacea-variant 4 4 (2-)3 i non-permanent grassland Bromus hordeacus-community 3(-4) 4 (2-)3 i Cynosurion cristati Lolio-Cynosuretum, Trifolium repens-facies, typ. var. 3 (3-)4 (2-)3 i Lolio-Cynosuretum, Alopecurus pratensis-variant 3-4 4 (2-)3 i Deschampsion cespitosae Ranunculo-Deschampsietum, typical variant 4 4 2-3 e Ranunculo-Deschampsietum, Carex gracilis-variant 5-6 4 2-3 e Carex hirta-community 3-5 (3-)4 (2-)3 f Calthion palustris Epilobio-Juncetum effusi, typical variant 4-5 3(-4) 2-3 i Epilobio-Juncetum effusi, Deschampsia cespitosa-variant 4-5 3-4 2-3 i Angelico-Scirpetum 5 (3-)4 2-3 e Agrostietea stoloniferae Potentillion anserinae Ranunculetum repentis 3 4 2-3 e Ranunculo-Alopecuretum geniculati, Alopecurus pratensis-var. 5 4 (2-)3 e Ranunculo-Alopecuretum geniculati, Phalaris arundin.-var. 5 3-4 2-3 e Ranunculo-Alopecuretum geniculati, Deschampsia cespit.-var. 5 3-4 2 e Ranunculo-Alopecuretum geniculati, typical variant 5 4 2 e Phragmitetea australis Phragmition australis Glycerietum maximae 4 (3-)4 2-3 e Caricion elatae Carex gracilis-meadow (4-)5 3-4 2-3 e Caricetum gracilis, typical variant 5-6 4 2-3 f Caricetum gracilis, Phalaris arundinacea-variant 5-6 4 2-3 f Eleocharito-Sagittarion sagittifoliae Eleocharitetum palustris 5-6 (3-)4 2(-3) e

w - „water”, n - „nutrient”, o - „oxygen in the soil”, i - intensive, e - extensive, f - without use (fallowland)w 2 - medium dry, 3 - fresh, 4 - moist, 5 - medium wet, 6 - wet up to very wetn 3 - medium rich in nutrients, 4 - richo 2 - temporary oxygen deficits in the soil (or in some layers), 3 - good oxygen supply


Fig. 10. Current land use and vegetation in Kleine Spree floodplain (from Schulze, 1997, and Bastian)

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Fig. 11. Rumex obtusifolius - an indicator of soil compaction in floodplain meadows near Kleine Spree river.

Fig. 12. Wet sites are often occupied by Carex gracilis-reeds.


It is obvious, that - due to natural suppositions (floodplain!) and intensive farming - the nutrient supply of the soils is high, in general! The ecological indicator values of the vegetation relevés were calculated with computer programme „Wild plant data and information system Terra Botanica” (Dahmen, 1994).

Arable fields The weed vegetation of arable fields (see Tab. VIII) is also characterized by high nutrient supply and low species diversity. Poor and acid types can be identified by Scleranthus annuus, and moist sites by Rorippa palustris, Gnaphalium uliginosum and others. The last mentioned type shows low values for „oxygen“ in consequence of a poor soil aeration.

Table VIII. Weed-communities of arable fields in the test area Kreba and their indicator values (calculated with „Terra Botanica”, see Tab. vii, X)

forests Tendencies of eutrophication, decrease in biodiversity and - partly - drying out can be observed in the forest communities, too. Among alder swamp-types of Kleine Spree floodplain, the stingle net - alder forest (Urtico-Alnetum) marks an essential poorer water supply, but higher oxygen and nutrient contents in the soil in consequence the mineralization of organic hydromorphic soils. Natural forests in the floodplain represent a transition form between the Stellario-Carpinetum - oak-hornbeam forest and the (original?) Pado-Fraxinetum riverside forest. There are also remarkable lowland spruce stands (Calamagrostio-(Piceo-) Quercetum) on peat soils which are threatened by drying out (see the low value for „water” - Tab. IX, Fig. 13, 14). Comparing analyses in moist forests (alder swamps, moist oak-hornbeam and oak-birch forests) of the biosphere reserve (Hoffmann, 1999) have also been carried out. For the 1950’s, forest site inventories (which focus soils and vegetation) were involved, and for the present time relevés of the actual vegetation were carried out and assessed with the help of indicator values (according to Ellenberg, 1974/79 and „Terra Botanica”): Some of the test plots suffer from groundwater lowering. Most of the relevés show higher nutrient supplies and an immigration or an increase of herb species

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which profit from better nutrient conditions (Urtica dioica, Impatiens noli-tangere, Oxalis acetosella). soils Generally, there are much less studies about changes of abiotic (physical) landscape factors such as soils (and waters).

Fig. 13. Old oaks as remnants of former riparian forests along Kleine Spree river.

Table IX. Forest communities in the test area Kleine Spree floodplain and their indicator values (calculated with „Terra Botanica”, see Tab. vii, X)


Large-scale changes in soil properties of the Upper Lusatian biosphere reserve are assumed due to drainage, acidic immissions (until 1990 but since then there is pH increase in precipitations from 4.5 up to 7), agriculture on peat soils, disconti-nuation of dung application, military activities until the beginning 1990 s. In the test area Kreba, detailed analyses were carried out (Syrbe et al., 1998; Röder, this issue). Actual field samples (in 1998) were compared with the German agricultural soil inventory (from 1951/52).The following changes and soil degradations were proved among other things:• Loss of humus in upper horizons of sandy soils.• Decomposition of peats.• Progressive podzolisation of former sandy gleys. From it, essential changes of site conditions result, which can be characterized in a complex manner by the potential natural vegetation.

Fig. 14. Poor pine forests on sandy dunes are characteristical for the region.

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potential natural vegetation

Potential natural vegetation (PNV) is a complex indicator for site conditions. It is a matter of the most developed vegetation appropriate to a site in a certain (in most cases the present) time. PNV was made as follows: the indicator values (water, nutrient, acid, oxygen) of actual vegetation relevés were determined and mapped in both test areas. With the aid of Terra Botanica, lists of wild plants which are adequate to the found site conditions (several combinations of indicator values are possible) were established. Only plants of the Saxon flora growing in forests (because almost only forests represent the PNV in this region) were considered. The list was precised and shortened with regard to the specific flora of the Upper Lusatian heath and pond region. Taking into account the final lists of possible forest plants for all occurring site conditions including personal knowledge of the regional flora and vegetation, available descriptions and existing medium-scaled maps of PNV (for Saxony) and soil samples of the test plots, highly-differentiated results were obtained (see Tab. X). For the utilization of historical soil data a „translation” of their ecological attributes into indicator values was ..., in order to (re)construct the historical PNV in a similar manner.

w 2 - medium dry, 3 - fresh, 4 - moist, 5 - medium wet, 6 - wet up to very wetn 2 - poor in nutrients, 3 - medium, 4 - rich, 5 - very richa 2 - acid (pH 4-5), a 3 - medium acid (pH 5-6), a 4 - slightly acid (pH 6-6.7), a 5 - neutral (pH 6.7-7.3), a 6 - mild, alcaline (pH > 7.3)

Table X. preliminary units of potential natural vegetation assignment to ecological indicator values - for the biosphere reserve „upper lusatian heath and

pond landscape”

(values for „water” 2-6, „nutrient” 2-4, „acid” 3, „oxygen in the soil” 3)


For areas that have been used for agriculture for a long time, it is not without any difficulties possible to determine PNV doubtless, because of possible soil changes that have occurred. A dominance of Molinio-Quercetum in 1951/52 on sandy gley soils of Kreba test area, however, is very likely. For the former humic gleys, bog gleys and wet bogs, variations of Molinio-Quercetum and Carici elongatae-Alnetum are characteristic. Podzols and regosols would still be covered with Agrostio-Quercetum. Besides, PNV is also influenced by the available nutrients. Actual vegeta-tion mapping indicates high and very high nitrogen contents. Thus actual conditions on the fields would probably be characteristic for Holco mollis-Quercetum or Carpinion betuli-forests (with moist and drier variants).

change of landscape functionality

With the aid of landscape functions (and natural potentials) it is possible to characterize landscape changes than by comparing structural attributes such as land cover (heterogeneity), vegetation and other isolated landscape factors. The conside-ration of landscape functionality should integrate different specific approaches and bridge the gaps between nature (science) and society in a transdisciplinary manner. The methodology „change of landscape functions” was already elaborated earlier and applied in case studies in Western Lusatia (Bastian, 1998; Bastian and Röder, 1998). For the Upper Lusatian heath and pond landscape the following changes of landscape functions are assumed (for the total area) and (or) proved by detailed analyses in the small test areas:– increase in biotic yield potential by drainage (and possibly by less acid precipita-tions

in the 1990 s),– reduced runoff regulation in consequence of floodplain reclaimation,– increase in soil erosion by wind (deflation) caused by drainage, conversion of gras-

sland into arable fields, removal of landscape structures, and humus decomposition (Großert, 1999; Röder, this issue),

– conversion of grassland into arable fields favours groundwater recharge,– habitat function was reduced, e. g. by land reallocation, intensification of farming,

losses of meadows, ecotones, structural elements, drainage, straightening of waters, waste inputs,

– decrease in the recreation potential / scenic values by the loss of structural diversity.

landscape management / conclusion

Applying a complex research programme, essential changes and threats of isolated factors and of the whole landscape system and functioning could be shown. The results are suitable to draft targets and measures of future management of the test areas and the whole biosphere reserve earlier – Upper Lusatian heath and pond landscape. There shall be mentioned only some aspects: The development of land use pattern and intensity can be related to changes of biodiversity (flora, fauna, habitats) and consequences for future land

52o. BasTian

use activities can be drafted (considering targets for plant and animal populations). Vegetation relevés emphasized serious losses of diversity and impacts by human influences. Especially, eutrophication is a crucial factor which should be diminished. Comprehensive investigations of the river course Kleine Spree and the adjacent floodplain are important contributions with regard to a possible future river revitalization. We propose the following measures: – at least maintaining, better increasing a high proportion of grassland, and its exten-

sive use,– favouring riparian woods which are typical for a floodplain, raising the groundwater

level and improving water retention capacity,– maintaining the ponds with their functions for a rich flora and fauna,– improving the Kleine Spree river ecosystem itself with regard to water quality, run-

off balance and dynamics, morphology, free intercharge of fishes and other water organisms.

Studies in Kreba area give advice for the restoration of a varied agricultural landscape. The changes of potential natural vegetation prove that past vegetation and landscape states can not be restored easily - apart from the fact that such a development is not absolutely desirable.

references

arnold u. (1998): Vegetationskartierung. Teichgruppe Lippitsch. Mscr. (unpubl).Bastian o. (1991): Historical and current land use changes in Saxon hilly areas

- ecological evaluation and consequences. In: Brandt J. (ed.), Proc. Europ. Seminar Internat. Ass. Landscape Ecol. (IALE), Roskilde (Denmark), May 2-4. 1991. Vol. 2, Roskilde Univ., pp. 33-43.

Bastian o. (1998): Change of landscape functions - consequences for ecological planning and management. In: Richling A., Lechnio J., Malinowska E. (eds.), Landscape transformation in Europe - practical and theoretical aspects. Warsaw , vol. III, pp. 201-242.

Bastian o.: Kleine Schwester der Spree - Die Aue der Kleinen Spree bei Milkel. Mitt. Landesverein Sächs. Heimatschutz, 1999, 2, pp. 27-37.

Bastian o. & Bernhardt a. (1993): Anthropogenic landscape changes in central Europe and the role of bioindication. Landscape Ecol., 8, 2, pp. 139-151.

Bastian o. & röder m. (1998): Assessment of landscape change by land evaluation of past and present situation. Landscape and Urban Planning, 41, pp. 171-182.

dahmen f.W. ( 1994): Das erste Wildpflanzen-Datenbank- und Informationssyste für Analyse, Diagnose und standortgerechte Planung von Natur und Landschaft. Rose GmbH, Blankenheim.

ellenberg h. (1974): Zeigerwerte der Gefäßpflanzen Mitteleuropas. Scripta Geobotanica, 78, 9.

giessübel J. (1993): Erfassung und Bewertung von Fließgewässern durch Luftbildaus-


wertung. Schr.-R. f. Landschaftspfl. u. Natursch., 37.großert a. (1999): Winderosion auf landwirtschaftlich genutzten Flächen im Biosphä-

renreservat „Oberlausitzer Heide- und Teichlandschaft”. Techn. Univ. Dresden/Tharandt (in print).

hoffmann h.(1999): Vergleichende Vegetationsuntersuchungen auf fünf ausgewählten Bruchwaldflächen im Biosphärenreservat „Oberlausitzer Heide- und Teichland-schaft“. Techn. Univ. Dresden/Tharandt (in print).

martin J. (1999): Zustandsbewertung der Kleinen Spree im Biosphärenreservat „Oberlausitzer Heide- und Teichlandschaft“ unter besonderer Berücksichtigung der Wasserbeschaffenheit. Techn. Univ. Dresden/Tharandt (in print).

schulz r. (1998): Methodische Aspekte einer historischen Landschaftsanalyse im Biosphärenreservat „Schorfheide-Chorin”. Eberswalder wiss. Schr., 2, pp.59-69.

schulze d. (1997): Landschaftswandel im Biosphärenreservat „Oberlausitzer Heide- und Teichlandschaft” / Aue der Kleinen Spree bei Milkel. HTW Dresden (in print).

syrbe r.-u., Bastian o. & röder m. (1998): Analyse und Bewertung der Landschaft und ihrer Veränderungen anhand ausgewählter Funktionen des Naturhaushaltes im Biosphärenreservat „Oberlausitzer Heide- und Teichlandschaft”. In: Erdmann K.-H., Bork H.-R. & Grunewald K. (eds.), Geographie und Naturschutz: Beiträge zu einer naturverträglichen Entwicklung,Bundesamt für Naturschutz, Bonn (MAB-Mitt. No 45), pp. 267-303.

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The assessmenT of landscape and vegeTaTion …31 The assessmenT of landscape... The assessmenT of landscape and vegeTaTion chang-es: The case sTudy – upper lusaTian heaTh and pond