Protection and development of limestone grasslands in the Swabian Alb

 

The following articles are summaries from the handbook: Protection and development of limestone grasslands in the Swabian Alb - Schutz und Entwicklung der Kalkmagerrasen der Schwäbischen Alb (ISSN 0342-6858) - Beiheft 83 - Veröffentlichungen für Naturschutz und Landschaftspflege in Baden-Württemberg, Karlsruhe 1995

  1. The limestone grasslands of southwest germany - a model for conservation and development of anthropo-zoogenic types of ecosystems

  2. Chances and limits of conservation managment of dry grasslands

  3. Conservation managment of calcereous grasslands

  4. Limestone grasslands and poor meadows: endangered biotopes of the Schwäbischen Alb

  5. Investigations to the fauna of frequently grazed limestone grasslands

  6. The potential vulnerability of plant populations in limestone grasslands on the Middle Swabian Alb by succession and afforestation - a coenotical approach

  7. The importance of transhumance for the interchange of species between isolated limestone grasslands

  8. Succession induced changes in the invertebrate fauna of limestone grasslands on the „Schwäbische Alb“

  9. Natural succession - an alternative development to limestone grassland of the „Schwäbische Alb“

  10. Economical aspects of nature conservation measures in limestone grasslands and low-productive meadows

  11. Economics of conservation and re-establishment of limestone grassland and low-productive meadows

  12. The importance of structural and surrounding area parameters for calcareous grassland

  13. Strategies for preservation and development of dry, nutrient-poor limestone grasslands.

(13-30) Plachter et Schmidt, 1993 :
The limestone grasslands of southwest germany - a model for conservation and development of anthropo-zoogenic types of ecosystems
In the European and Anglo-American societies nature and human culture are understood to be strictly opposite. This is reflected in the basic concept of nature conservation as well, as the crucial goal is the protection of „untouched“ nature against human influence. Adopting this, man is compulsatorily the intruder, disturbing the ideal order of nature by whatever activity he carries out there, thus lowering the intrinsic value of the natural elements of the biosphere. In the light of actual scientific data this puritanical attitude has to he questioned. Even in historic periods man’s influence on nature had been more extensive than it was believed for a long time. Untouched nature nearly no longer exist on eatth. This comes especially obvious in the Central European cultural landscapes. Here the substantial influence of man on the landscapes not only dates back for at least 6,000 years. Moreover: the mass of the native fauna and flora is linked to anthropo-zoogenic types of ecosystems, which owe theirs existence to very specific kinds of landuse. Many of those landuse techniques became unusual or economically unprofitable in recent times. By this the question has to been asked, whether and how far it is a task of nature conservation itself to protect and encourage those historic landuse practises. Alternatives could be the substitution of landuse by a specific nature conservation management or the renunciation of any use or management in favour of a undisturbed semi-natural succession.
In Central Europe various grassland ecosystems are very characteristic types of anthropo-zoogenic habitats. Although the losses had been immense during the last 150 years, even nowadays they are wide-spread in many areas thus determinating the visual quality of the landscape and are still persisting in spatial connectivity of adjacent areas. In historic landuse systems those ecosystems usually had been sources for nutrients (grazing of lifestock; taking off biomass by harvesting without adequate substitution by fertilizers). They therefore actually belong to the most nutrient-poor ecosystems in the commonly over-fertilized landscapes of Central Europe, which - together with a huge amount of endangered species -justifies their high protective value. Recent losses are either due to a chance to modern kinds of landuse including fertilization or conversation to fallow land, often followed by reforestation. In the past nature conservation normally seeked to compensate those landuse changes by substitutional management carried out by or for account of the nature conservation agencies (in Germany: socalled „biotope-care“) or contracts with farmers which guarantee financial compensation for the maintenance of unprofitable kinds of historic landuse. Despite of the fact that a statical, conserving management ignores the intrinsic dynamics of populations and ecosystems, the number of fallowed areas has grown to an amount in recent days which exceeds the financial and organisatorical capabilities of nature conservation agencies and NGOs by far. Among the grassland ecosystems of Central Europe dry meager types, especially those on limestone, play an extraordinarily role. In several regions they clearly determine the feature of the landscapes. One of those regions is the „Schwäbische Alb“, a mountainous region in southwest Germany (State of Baden-Württemberg), elevating to 700 to 900 meters above sealevel. Most of the dry nutrient-poor grassland there owes its origin to traditional sheep keeping, which was carried out by shifting grazing during the whole year. Summer and winter pastures were often separated by hundreds of miles. The flock of sheep normally stayed only some hours or days on one specific area, than turning to a neighboring one. It is obviously that this landuse system is no longer very attractive regarding the international market as well as regional economic and social features. Linked to this system of pastures are several types of dry meadows which delivered fodder for sheep and cattles within the traditional agricultural systems. Those ecosystems are at least as endangered as the dry pastures. For the comparative evaluation of different types and successional states of this nutrient-poor grassland and for the development of strategies for protection and management of those stands the Ministry of the Environment of the State of Baden-Württemberg placed a scientific research project in 1991. The results ought to be applicable to other regions and to similar types of grassland ecosystems.

The project was carried out in close cooperation by nature conservation scientists and economists. A permanent working group of officials, practical experts and scientists took care of the implication of the results in practical work and the specification of methodological regulations in the fields of évaluation and planning.

Important questions of the scientific work had been among others:

  • Are the normal kinds of habitat management effective?
  • Is a static protection of those man-made ecosystems possible at all?
  • Which methodologies are adequate for the comparative assessment of areas and various kinds of landuse?
  • What is the history of landuse in this region in detail? Can historic states of landuse be a reference for the future development of those grassland ecosystems?
  • What types of succession occur on fallow land?
  • Will there be again valuable stages within the successional course, which justify the decision to use certain areas not any longer?
  • Is therefore semi-natural succession an equally worth alternative to persisting landuse?
  • Is it possible to restitute the historic pathes between the pastures for the flocks of sheep, also to improve biological conductivity ?
  • What are the social and economic key factors, which cause the growing unattractiveness of sheep keeping?
  • Are there ways to improve these factors?
  • Are there possibilities to reduce the proportion of public subsidies in the income of the enterprises by offering new chances on the public market?
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(31-36) Petermann, 1993 :
Chances and limits of conservation managment of dry grasslands

In the past 30 years measures of mechanical biotope care have been regarded to be the sole option in order to prevent further loss of limestone grasslands in the swabian alb region. It is the current goal of conservation managment to preserve the remaining sites in face of a continuing decline of sheep herding and other uses of meager grasslands. Site preservation is limited by the amount of funding and personal available for managment purposes. Thus, even in large nature preserves, sucession still takes its toll, further reducing the spatial reducing of limestone grasslands. There is reason to believe that replacement of sheep grazing through mowing is not a desirable general strategy, as it will lead to a shift in floral and faunal composition and ultimately is bound of increase the degree of uniformity between different grassland sites. Therefore, managment of limestone grasslands should aim towards a mixture of pastoral use and mechanical managment. In this context and for economical reasons, large unfragmented grasslands are best suited for sheep grazing. Active mechanical managment should be concentrated on small, isolated sites and the occasional removal of shrubs in large pastures. In spite of numerous attempts to re-establish pastoral use of limestone grasslands sucess has been sparse. Currently, only a increased effort in mechanical managment can secure the present status of the remaining grasslands. Such efforts are necessary to at least maintain the basis for a future re-emergence of the pastoral use of these grasslands. - back to top

(37-63) Schumacher et al :
Conservation management of calcereous grasslands
The Central European calcareous grasslands are almoust all man made and when not being cultivated anymore, a constant maintenance is necessary in order to preserve them. The respective maintenance programs should be developed in such a way that a considerable integration of agricultural use and maintenance is achieved. Keeping up or reintroducing an extensive form of land use should be prefered to pure maintenance because of reasons concerning the economy of nature, the ecosystem and agricultural structures. Generally, maintenance through utilization (keeping up an old form of land use that isn`t profitable anymore by directed financial aid) and maintenance without any form of land use are distinguished. Reconditioning is understood to be the regeneration of a poor grassland that has been lying fallow or been left to turn to scrubland since a considerable amount of time. It is a measure that is only carried out out once and is especially intended to rapidly remove the dead grass covering, in addition to the scrub removal. On the other hand maintenance through utilization (tending or paddock grazing, with sheep or other livestock) should preferably by organized. - back to top

(109-126) Beinlich und Klein :
Limestone grasslands and poor meadows: endangered biotopes of the Schwäbischen Alb
The limestone grasslands (mesobromion) are to be found on former forest sites and only evolved over the centuries after forest clearing and subsequent grazing. Two types are distinguished: the mowed mesobrometum (limestone meadows) and gentiano-koelerietum (limestone pasture). Especially in this century the once widespread areas of limestone grasslands have diminished to a great extent: about 50% have disappeared from the Alb since the beginning of the century, outside the alb the losses are about 80-90%. In Baden-Wuerttemberg supposedly about 150 km² of poor grasslands are still to be found. The dry and economically poor meadows on limestone, which are closely related to the above mentioned biotopes, are to be found within the alb area in three different forms: the valley and mountain oat-grass meadows and the "Mittelgebirgs" or cranesbill-yellow oat-meadows. Just as the actual poor grasslands, the dry and economically poor meadows are also diminishling rapidly. The losses since the beginning of the 20th century are estimated to be around 90%. All above mentioned types of grasslands are extremely colorful flowered habitats. The importance of limestone grasslands is due to their great number of drought and heat resistant plant and animal species and of warmth needing species with a main area of distribution further south. Additionally, many species have found a refuge here from the intensively used modern agricultural landscape where no other richly flowered habitats can be found. - back to top

(159-180) Walther :
Investigations to the fauna of frequently grazed limestone grasslands
The Swabian Alb (South-Western Germany) is one of the last centres of transhumant sheperding in Central Europe. Frequently grazed (Grazing intervall about three weeks) and adjacent little or ungrazed limestone grassland sites were compared by inventorying four invertebrate taxa: Carabid beetles (Coleoptera), land snails (Gastropoda), grasshoppers (Saltatoria) and butterflies (Lepidoptera). The largest part of the land snail coenosis is made up of thermophilous and subthermophilous species, of which even the most abundant ones are considered to be endangered. Most of these species prefer short grass with a high proportion of bare ground. Trochoidea geyeri has a disjunct range in central Europe. One of its largest populations is found on the limestone grasslands of the Swabian Alb studied here. Sites with little vegetation cover regularly harbour geophilus grasshopper species. In general species favouring xerothermophilous conditions are rarely found in these parts of the Swabian Alb for climatic reasons. Stenotopic carabid beetle species prefer short grass in open areas. But, by far the most abundant species is Clathus fuscipes, an euryoecious species of open areas. It makes up almost two thirds of all individuals. Percentage of specialists that require the close interconnection of grazed and ungrazed tracks at the edge of limestone grassland sites is high in the Lepidoptera fauna. Diversity is higher on less grazed patches. Species typical for open areas, like Lysandra coridon or Melanargia galathea are most abundant on short grass. • High intensity of grazing does not necessarily lead to the degradation of a limestone grassland site for nature conservation. This type of land use can create essential habitat structures for specialized species if it is part of a mosaic of similar habitats on a landscape level. - back to top

(199-226) Poschlod et al:
The potential vulnerability of plant populations in limestone grasslands on the Middle Swabian Alb by succession and afforestation - a coenotical approach
In the region of the „Middle Swabian Alb“ the potential vulnerability of plant populations of calcareous (limestone) grasslands to succession or afforestation was investigated. A data base for all 187 species, occuring in the calcareous grasslands of this region, was constructed. The collected data were life and growth form parameters, the persistence of the shoot and generative diaspore population along the successional sere (investigated by field observations and experiments) and the dispersability. Dispersability was studied by a morphological classification and by field observations of dispersal by sheep. Pollination also was classified to look for a possible viability by missing or reduced geneflow. The greatest part of the total species pool seems to have a low vulnerability to succession and afforestation. Shoot or generative diaspore populations can still survive in older succession stages. But for many species the dispersal by sheep is the only possibility to survive by recolonizing suitable sites. Between 30 and 40 species are strongly endangered by succession and afforestation because the shoot population cannot survive in older succession stages and the generative diaspore bank is transient. Also dispersability is very low. Most of the species are already in the Red Data Book of Baden-Württemberg, but some not yet like Anthyllis vulneraria, Asperula cynanchica a. o. lf the trend of fallowing of liniestone grasslands is still going on populations of these species will diminish and partially die out. Therefore succession as an aim of nature conservation should be only a part of the management of calcarcous grasslands. An extensive management concept could be a „directed mosaic-cycle“. An afforestation as a management tool to avoid colonization by clonal shrubs should be only an exceptional case. - back to top

(229-256) SABINE F. FISCHER, PETER POSCHLOD und BURKHART BEINLICH : The importance of transhumance for the interchange of species between isolated limestone grasslands
During the vegetation period 1993 a transhumant flock of sheep on the Swabian Alb was examined concerning the question which plants and animals are transported in the wool, hooves and the digestive tract of sheep within a calcareous grassland. Furthermore, experiments on dispersal using marked diaspores and grasshoppers on two tame sheep were carried out in order to find out their retention time on sheep. During the time of research 108 vascular plants and 27 animal species were discovered in the wool, hooves and excrement of the Münsingen flock. The wool proved to be the most significant medium for the transportation of plants: during 16 intensive examinations of the fleece of a single sheep over 8500 diaspores of 85 vascular plant species were found. The experiments with marked diaspores showed that diaspores, once attached to the fur, can be transported over months and consequently over the entire roaming area of the sheep. However, many plant species are transported in the hooves and digestive tract of sheep. The hooves of 30 sheep contained over 380 diaspores of 48 vascular plant species and in the excrement of 105 acts of defecation 270 diaspores capable of germination from 27 plant species were fotind. Amongst the animals which are transported by sheep only grasshoppers (13 species) and snails (7 species) were found frequently in the fur and hooves respectively. During the experiments with marked grasshoppers the average period of time the grasshoppers stayed on the sheep was 14 minutes. Over this period of tame sheep cover a distance of over 100 m when grazing and well over 500 m when roaming. Most of the snails were transported in the mud stuck under the hoover. In the hooves of 30 sheep 18 shells of mainly srnall species and juvenile snails were discovered. The results of this research prove that the importance of shepherding, especially of transhumance, is more diverse than first assumed. Sheep did not only shape the calcareous grasslands by trai-npling and browsing, they are also responsible for an interchange of species between the grazing through transportation of plants and animals. In this way the spreading isolation effects in our greatly fragmented landscape of today, which are increasingly endangering those organisi-ns with a weak capability of dispersal, can be reduced. Additionally, this Transport is also essential for the regeneration of grasslands having been left fallow over a tonger period of tii-ne: plants and animals with weak capability of dispersal, which have meanwhile disappeared from the feillow land can be reintroduced to these areas by sheep.- back to top

(283-310) BURKHARD BEINLICH:
Succession induced changes in the invertebrate fauna of limestone grasslands on the „Schwäbische Alb“

The effects of fallowing and the intrusion of shrubby vegetation on selected invertebrate groups (butterflies, grasshoppers, snails, ground beetles and ants) was studied. As succession proceeds, the number of species characteristic for limestone grasslands declines. This includes threatened and endangered species. Intensively grazed limestone grasslands provide suitable habitats for 50-60 endangered species, as compared to about 20-30 endangerd species found to be associated with different successional stages. Depending on the invertebrate group considered, maximum species richness is associated with different successional stages. As shrubby vegetation cover surpasses 30 % of the grassland area, a rapid decline of species numbers was observed in the ground beetles. In contrast, species numbers were found to increase as succession proceeds from early to medium stages in the butterflies and ants. The presence of meager, short grass successional stages is particularly imponant for grasshoppers, snails and ground beetles. In these groups 40 % of all the species in limestone grasslands are associated with early successional stages. As succession proceeds to the final beech-forest stage, the number of taxa with close habitat ties is bound to increase again in the snails and ground beetles. From a conservation perspective, the communities associated with late successional stages are, however, less valuable than those associated with intensively grazed grasslands or early successionalstages.- back to top

(311-336) BURKHARD BEINLICH, DANIEL HERING und H. PLACHTER:
Natural succession - an alternative development to limestone grassland of the „Schwäbische Alb“

Limestone grasslands have always been influenced by changes in land use. Consequently, fallow land and the spreading of bush is not only an occurrence of the present. However, the continuous intensification of cultivation in the form of ley farming seems to have played a more essential role throughout the history of limestone grasslands than the abandonment of land use followed by development of bushland or respectively forest. Today, succession to forest constitutes the main cause of endangerment to the existence of limestone grasslands. The course of succession is determined by numerous factors (e.g. former land use, soil depth, water balance, degree of bush covering, propagation and dispersal mode of occurring plants or the behavior of certain animals) and can therefore proceed differently on similar sites. Ultimately, the different courses of succession all proceed toward a collective stage. This being one ofthe different types of beech forests depending on the respective site. In the Schwäbisehe Alb-area the courses of succession on the escarpment ridge differ distinctively from those of the Alb highlands. On the escarpment ridge deciduous trees predominate the succession. Of great importance in this case is blackthom, Prunuss spinosa, which spreads over polycormones, tends to form a pure stand and as a result is difficult to be rid of through maintenance measures. The succession processes on the Alb highland, on the other hand, are mainly determined by conifers (esp. Pinus, Picea and Juniperus). Prunus spinosa grows poorly here and consequently only plays a subordinate role. After ceasing land cultivation bush generally spreads essentially slower on mowed limestone and pooreconomic grassland than on abandoned pastures. This is mainly due to the absence ofbare ground, which serves as a germinating bed for the seeds, and due to the land becoming matted after cultivation stop. Considering that under the conditions of the Alb highlands no sequel stage would even approximately attain the value of regularly sheep-grazed open limestone grasslands and in addition considering the possible implementation of similar succession processes on other fallow areas, succession can not be contemplated as an altemative development to limestone grasslands from a nature conservation perspective. Also the large portion of succession forests in comparison to the areas of intact limestone grasslands on the Alb speak against this thought - acoording to evaluations of five forestry departments this portion lies at an average of about 57 %. - back to top

(349-358) KLAUS TAMPE:
Economical aspects of nature conservation measures in limestone grasslands and low-productive meadows
To conserve historical landscapes in regions characterized by calcareous grassland and other types of low-productive pastureland requires cost-intensive measures to be taken. These comprise both reconditioning measures and, once the desired state of the landscape is attained, provisions suited for its maintenance. Reconditioning measures have to be taken only once at the start of a conservation programme and are necessary whenever the areas lack the required properties due to former neglect. In general, trees, shrubs and other woody material have to be removed. The maintenance measures subsequent to reconditioning have to be taken continuously, and a distinction has to be drawn between what might be termed „pure maintenance“ and „maintenance through utilization“. While in the former case no (or almost no) goods are produced for the marketplace, the latter are to be characterized as traditional land-use practices aiming at producing agricultural goods, although at a very extensive level by to-day’s standards. In general, „maintenance through utilization“ schemes are to be preferred to those based on „pure maintenance“ for various reasons. „Pure maintenance“ measures should only be taken in special cases or temporarily. They comprise the mowing of meadows without utilizing the vegetable matter as fodder (although it might be necessary that it must be removed from the areas and disposed of), the grazing of pastureland without the animals achieving any significant economic value, and the regular removal of woody plant material. Measures characterized as „maintenance through utilization“ imply traditional haymáking and, especially on limestone grassland, sheep grazing which is a case in point. Obviously, „pure maintenance“ measures must be paid. Additionally however, prevailing conditions preclude any economic profitability of extensive land-use schemes, if they receive payments only from the sale of their marketable products. Therefore, „maintenance through utilization“ measures must receive an additional remuneration for their ecological services, too. In both types of measures, annual costs can be calculated without difficulty. However, if the total cost of land developement schemes are to be calculated on an annual basis, costs incurring only once (such as for reconditioning measures) or at regular intervals (such as for capital goods like machinery and buildings) have to be transposed into rents respectively annuities, according to the rules of financial accounting. In addition to the settlement of real costs involved in landscape development, further payments may be necessary if certain land-users are both physically capable and legally entitled to apply practices not in accordance with regional conservation objectives. For instance, they may be willing to crop their land intensively, applying high amounts of fertilizer and pesticides. They are persuaded to abstain from intensive land-use and to cooperate in conservation schemes only if they receive compensation payments which make them at least as well-off as if they did not cooperate. Although the necessity to resort to compensation payments such as these may also emerge in the region regarded here, it is advocated that land-use conflicts of this kind must be resolved in other ways. The parties not willing to cooperate in conservation should be offered areas outside the region in exchange, where they may continue their intensive land-use.- back to top

(361-388) KLAUS TAMPE und ULRICH HAMPICKE : Economics of conservation and re-establishment of limestone erassland and low-productive meadows
In search for strategies for the conservation and ecological development of limestone grassland, other pastureland and low-productive meadows in South-west Germany (Schwäbische Alb), reference has to be made to human activities which have generated these ecosystems in past centuries. The case in point are sheep-breeding and extensive haymaking. Both utilization schemes are analyzed from an economic point of view, focussing on two aspects: Firstly, costs and revenues from the sale of marketable products are elicited. Secondly, their usual financial deficit is established in order to estimate the necessary funding which these activities must receive in order to make them economically sustainable. This funding can be interpreted as a remuneration for valuable ecological services. Today, sheep-breeding is run both by migratory and stationary herdsmen. Seasonal migration being increasingly on the decline due to various obstacles such as missing cattle-tracks and pasturages utilizable during the winter, the strategies suggested here focus on stationary systems. Sheep-breeding in the region „Schwäbische Alb“ is centred around two military training areas near the towns of Münsingen and Albstadt. Save exceptionally favourable circumstances (for instance the possibility to sell products at the farm to tourists or restaurants), both migratory and stationary systems perform poorly in economic terms if all cost components are considered properly in the calculation. This is true even allowing for current subsidies. Since 1993, sheep-farms grazing their droves on chalk grassland classified by the Nature Conservation Law (§ 24a NatSchG) of the land Baden-Württemberg, improve their income considerably by receiving DM 200 per hectare and year from the land’s conservation programme (MEKA). Yet this improvement fails to assure a complete coverage of all costs in stationary sheep-breeding. For the latter system to be sustainable, provision has to be made not only for a winterproof sheepshed but also for a well-designed scheme of fodder supply implying sufficient areas of energy-rich supplemental green food in addition to the poorer material growing on the limestone grassland. Further requirements concern pasturages utilizable during autumn and, of course, sufficient hay resources for the winter half-year. If, on the average, four ewes graze on one hectare of limestone grassland, one hectare of summer pastureland requires the addition of 0,08 hectare of supplemental green food, 0,17 hectare of autumn pastureland and 0,44 hectare for meadows for haymaking. It is assumed here that lowly-productive haymeadows are used in order to conserve their ecological qualities. According to the economic analysis carried out here, the stationary sheep-breeding system is, under normal conditions, characterized by the fact that the disproportional or ftx costs exceed the receipts from sales of meat and wool, calculated in pure market prices (less proportional costs), by DM 1048 per hectare and year. The most important cost components are wages, annuities for the sheepsheds and the reconditioning measures (removal of shrubs and trees from the pasturages) although the latter accrue to the public rather than to the sheep-farm. If society wishes sustainable sheep-breeding to be continued in order to conserve the countryside in the region, roughly DM 1000 per hectare and year must be made available in one form or another, additionally to the earnings from product sales, calculated in market prices. All subsidies already in existence, such as payments per ewe or per hectare, resulting from landscape preservation programmes organized by the EC or by the land BadenWürttemberg and from other sources, sum up to roughly DM 600 per hectare and year, so that the remaining deficit totals about DM 400 per hectare and year, of which DM 240 are allotted to reconditioning measures. The economic analysis of haymaking on low-productive meadows yields a somewhat different result. Assuming a wage rate of DM 15 per hour and allowing for all fix and proportional costs, the system yields an economic deficit of about DM 300 per hectare and year if the hay is marketed at current prices (1993). In most farms, this deficit is fully covered by current subsidies so that no further funding appears necessary, assuming that the economic circumstances do not deteriorate in the future. An important contribution in this respect is the provision for consolidated hay-markets which can be assisted efficiently by the establishment of a sustainable sheep-breeding system in the same region and its continuous demand for hay during the winter season. - back to top

(391-406) DANIEL HERING & BURKHARD BEINLICH
The importance of structural and surrounding area parameters for calcareous grassland

The composition of calcareous grassland biocoenoses depends to a great extent on different structural and surrounding area parameters. The area size and the distance to other calcareous grasslands influence the probability ofpopulation survival and consequently also the species inventory. Additionally, the habitat conditions and the occurrence of certain animal species are greatly determined by the exposure and the vegetation structure. Further factors that contribute to the forming of calcareous grassland biocoenoses are the density of shrubs, the soil structure and the occurrence of typical special sites. The effect of the mentioned parameters on calcareous grassland biocoenoses is documented in the literary references and our own research data. These effects are further clarified by examples. - back to top

(441-463) HARALD PLACHTER UND BURKHART BEINLICH
Strategies for preservation and development of dry, nutrient-poor limestone grasslands

Even in historic time man has had a decisive impact on nature. This resulted in the creation of new ecosystem types. The human impact is particularly striking in the Central European cultural landscapes, where historic landuse systems created a fine-grained mosaic of natural, semi-natural and anthropo-zoogenic ecosystems. Historic landuse practises are essential for the continued existence of many specific ecosystems but they are increasingly replaced by modern landuse techniques. Recently, not only intensification but cease of use as well has tumed out to be a problem for conservation. Fallow land is often preserved through substitutive management by nature conservation institutions. But the capacities for this kind of management are limited and its impact frequently differs significantly trom the historic one. Thus, in spite of the management efforts, the anthropogenic ecosystems change. Dry, nutrient-poor limestone grasslands (Mesobromion) are still common in several parts of Central Europe, considerably shaping the visual qualities of the landscapes and providing habitat for many species. Originally these grasslands either had provided hay (meadows) or they had served as pastures. The pastoral use mainly was tied to migrating herdes. The pastures served as nutrient sources within the complex historic landuse systems and thus owe their existence to unsustainable practices. For several reasons dry, nutrient-poor calcareous grassland can serve as a very delicate model for a future management and development of anthropo-zoogenic ecosystems which is in line with the goals of nature conservation. In this context a study was carried out in limestone grasslands of South-west Germany (State of Baden-Württemberg). The historic landuse types are no longer profitable. Therefore, to preserve their high degree of biodiversity an increasing number of areas has to be managed by nature conservation institutions. Even today the number of areas exceeds the capacities of these institutions. Therefore the frequency and degree of management impacts is considerably lower than in historic times. It is not sufficient to preserve a specific state of succession in a long-time perspective. Recently, the protection of natural ecological processes has been identified to be an imponant, independant goal of nature conservation. Natural succession is such a process. However, it is doubtful whether for limestone grasslands succession would be a general acceptable alternative to historical usage patterns. In fact there is not one single strategy which is applicable to all grassland ecosystems types but a series ofalternatives ofprimarily equal importance. The decision for one of these alternatives has to be made on a local level, taking into account general landscape scenarios for the future development of the region. For dry, nutrient-poor limestone grassland in South-west Germany those alternatives are:

1. Promotion and restitution of sheep keeping under a grazing regime, where the flocks are kept in stables during winter while they are herded between pastures during the rest of the year. In this scenario winter stable and the winter feed are economically sensible factors. Improving profitability therefore means to lower the costs for these factors within the economic balance of the entire enterprises.

2. Promotion of adequate agricultural practices for nutrient-poor grassland. This strategy especially - but not only - refers to nutrient-poor and mesophilic meadows. Measures include governmental subsidies as well as regional marketing strategies. By linking strategies I and II, winter feed can be provided to sheep keepers from nutrient-poor grassland thereby increasing profit margins for an extensive landuse system.

3. Preservation and management of out standing areas which lost their historic types of use. Due to limited capacities and general ecological considerations this strategy must be confined to few areas.

4. Preservation of the regional set species diversity. In many regions nutrient-poorgrassland is already restricted to small and isolated areas. If these areas are lost, many species will vanish from large regions. In this case, even if the situation improves in future, re-colonization is not very probable. Thus the persistance of those relict areas is highly important.

5. Succession. If none of the above strategies turns out to be useful for a specific area, succession can be an appropriate alternative. But a decision in favour of succession must take into account, that in South-west Germany a considerable part of former grassland has been left to succession in the past decades.

The resulting forests are excellent starting points for the implementation of „process reserves“, but an inventory of those areas is still laking and the knowledge concerning their actual state is still poor. Some military training areas prove to be outstanding staIting points for the implementation of those strategies. This is particularly true for the strategies I and II. Management of those vast areas depends on sheep grazing, this being a promising basis for economically profitable enterprises.

 

 
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