De Levende Natuur nummer 6 van 2003 (English summary)


Ecologische netwerken


DLN 2003-6

Natura 2000: the European implementation of the Bird and Habitat Directives

Decleer, K. & P.C. de Hullu

The Bird directive (1979) and Habitat directive (1992) of the European Union establish a legal basis for nature conservation in the countries of the Union. The implementation of this directive is named Natura 2000, aimed at the realisation of an ecological network of special conservation areas in the European Union. Allocation as a special conservation area is solely based on ecological criteria. Implementation resulted in 23 and 70 of such areas for 27 and 44 bird species in Flanders and The Netherlands respectively.

The Netherlands located 141 Habitat directive areas and Flanders 38. In both countries selection of the marine areas is not yet completed.

Both countries had to adapt the legislation to implement the directives. Flanders adapted in 2002 the laws partly; The Netherlands expects to be ready end 2003. After the process of selection of the areas the area targets need to be formulated and when necessary, management plans developed.

Assesments for the Bird directive need to be done every three year, for the Habitat directive every six year. In both countries the adequat monitoring system still has to be developed.

The Dutch Ecological network, backbone of the National Nature Conservation Policy

Bos, J. & P.C. de Hullu

Construction of the Dutch Ecological network, consisting of 775.00 acres, will interconnect nature reserves. It started in 1975 and should be finished in the year 2018. At this moment forty two percent of the targets set in creating new parts of this network have been realised, with another 190.000 acres to go. The former Dutch Government, i.c. the first 'Kabinet. Balkenende' reduced the budget for acquiring and developing nature reserves, resulting in a large gap in the finances. The present Government, i.c. the second 'Kabinet Balkenende' largely reduced the budget cuts. Major challenge in the next years is to achieve the planned quality of natural habitats within the network. This largely depends on the amount of reduction of external influences, -like deposition of nitrogen and implementation of watertable changes-, and finding a way to solve the problem of fragmentation of habitats. The network in its present shape offers to little connections to serve the migration purposes. It also lacks on natural habitats with a size large enough to ensure populations can maintain themselves. With the rapid changing climate in mind, this can be a major threat on biodiversity. Therefore, creativity is required to take measures, to find additional funding and to create new planning methods in order to complete the ecological network in the year 2018.

More money available for the Dutch National Ecological Network, but no guarantees that targets will be achieved; G.H.P.

Dirkx, G.H.P. & M.C.H. Witmer

The Dutch government plans to invest an extra amount of 400 million euro in the National Ecological Network (EHS) in the years 2005-2007. Also the government shifts from purchase of land for the EHS to nature management by farmers or other private land owners, thus postponing the expenditure. Up to now though, the number of agreements concluded for private nature management have stayed far behind the targets. Under the current delineation the EHS is fragmented and does not form a network. Pollution continues to hamper the quality of nature. Deposition of nitrogen e.g. exceeds the critical loads in most nature conservation areas. The content of phosphorus in the waters is far too high for succesfully controlling algae blooms. As a result, animal and plant species are threatened with extinction. Half of the species protected by the EU Habitat Directive and a quarter of the species protected by the Bird Directive, decrease in number. The Dutch North Sea is part of the EHS. Dutch fishery is the most importent threat to this ecosystem. Especially species that live at or near the bottom of the sea, decrease in number

Building an ecological network in Flanders (Belgium): slowly but steady?

Decleer, K.

To tackle further loss of biodiversity and nature fragmentation in Flanders a legal framework was approved in 1997 for the delimitation and implementation of a coherent ecological network. In the ‘Flemish Ecological Network’ (FEN) nature is the primary function and a total area of 125.000 ha needs to be designated before 2007. In September 2003 a first part of 85.000 ha was approved. Important consequences are e.g. the right of pre-emption for the government and the availability of a set of instruments for maintaining and improving nature quality. In the future the FEN areas will be supported by 150.000 ha of ‘nature areas with mixed or equally important functions’. Management agreements will be the key instruments here. Additionally Corridor Areas will be delimited by the provinces to increase the migration capacity of wild flora and fauna between the core areas mentioned above. For all these categories the ecological objectives and measures will be elaborated in ‘Objectives Nature Plan’. The most important problems and obstacles for a successful implementation are: lack of harmonisation between different laws and other planning procedures, low political priority, not enough public support (especially amongst farmers and land owners), no clear deadline for the effective realisation in the field of all the ecological objectives and very complex regulations.

Nature report 2003 in Flanders: nature cannot live in reserves only

Dumortier, M., A. Schneiders & E. Kuijken

The report on the state of nature in Flanders (2003) concludes that the downward trend of biodiversity has not stopped, although lists of protected species, reserves and protected areas do exist. Atmospheric deposition, roads and sluices and many more external factors still have a negative impact. The public and policy support for nature conservation increases. Other policy fields are slowly exploring more nature oriented approaches. This is most obvious in forest and water policy. Communication is essential to enhance co-operation.

Changes in nature policy for the National Ecological Network of The Netherlands: indication of effects on species

Oostenbrugge, R. van, W. Geertsema, J.A.M. Janssen, M.J.S.M. Reijnen & C.C. Vos

The Dutch government has recently made a number of changes in the process of realisation of the National Ecological Network (EHS). One significant change is that the policy of purchasing land for nature conservation organisations to protect current nature and to develop new nature, will shift towards management agreements with the current, mostly private and agricultural land owners. The assumption of the government that this change will not affect the final ecological objectives of the nature policy plan, has been doubted by nature conservation organisations and lower authorities. However, it is recognised that this will delay the process of realisation of the EHS. Moreover, this new policy will lead to delay of the final realisation of the EHS.Using Alterra’s expertise it was possible to indicate the effects for mammals (excluding bats), breeding birds, fresh-water fish, reptiles, amphibians and butterflies. Of these groups, species on the Dutch Red List (threatened and strongly threatened) and on the EU Bird and Habitat Directives were considered to be potential risk species. For more than half of these species, there is a relative high risk to become extinct when the process of realisation of the EHS is delayed, either due to a small dispersal capacity or a large area demand.Several semi-natural ecosystems do not endure agricultural use. Fens, springs,ecosystems determined by seepage and isolated species-rich grasslands are particularly vulnerable. As a result, species that are dependent on these ecosystems incur an increased risk. The risk is indicated for dragonflies, grasshoppers, land beetles, night moths, fresh water macro-invertebrates, vascular plants and mosses. Of these groups species on the Dutch Red List (threatened and strongly threatened) and the EU Bird and Habitat Directives were considered to be the most potential risk-species. More than one third of the considered dragonfly and macro-invertebrate species and approximately one quarter of plant species incur an increased risk due to the change in nature policy.

Ecological targets and the implementation of the ecological networks concept on a regional scale

Verschoor, G. & F.W.B. van den Brink

The improvement of the ecological quality of streams and nature conservation areas, including forests and landscapes, is one of the major goals of (inter)national and regional policy plans. Within the province of Limburg (the Netherlands) the streams and nature conservation areas together form a network of protected areas, as a part of the European Ecological Network, Natura 2000. For the implementation and execution of the policy plans, the abstract goals have been elaborated into concrete ecological targets for the restoration and management of streams and nature conservation areas. These ecological targets are set for natural and semi-natural circumstances, and are based upon historical and geographical references, together with information on the present abiotic environment and ecological values. All targets have been described and illustrated in the Handbook of Ecological targets for Nature Conservation and Stream Restoration in Limburg. Its is the aim of the Handbook to stimulate communication on ecological targets within the ecological network of protected areas, and thereby the start-up of new initiatives on nature and stream restoration projects.

How important are agri-environment schemes for the establishment of the National Ecological Network in The Netherlands?

Kleijn, D.

The Dutch National Ecological Network (EHS) consists of a mosaic of Environmentally Sensitive Areas ('Beheersgebieden'), where farmers can enter agri-environment schemes, and nature reserves. Recently there has been a lot of discussion about the most efficient way to conserve the Dutch natural diversity. Should more agricultural land be bought and converted into nature reserves or should money be invested in agri-environment schemes at the expense of land acquisition for reserves? This paper poses that the two approaches have different objectives. Nature reserves aim to conserve vulnerable species and threatened ecosystems. Agri-environment schemes aim to conserve basic natural values in agricultural landscapes. Only the conservation of meadow birds is being addressed by both approaches. Within the EHS, nature conservation by means of agri-environment schemes and the creation of reserves should therefore be made complementary. This can probably be done most effectively by clustering areas with agri-environment schemes around nature reserves. In this way areas with agri-environment schemes act as buffer zones between intensively farmed areas and the vulnerable ecosystems in the reserves. In return, the more species rich reserves can act as a source of species that may easily colonise nearby areas with agri-environment schemes.

What is the minimum area of a nature reserve?

Berendse, F.

It is a complicated task to determine the minimum area of nature reserves that is required to maintain their biodiversity. Important considerations are: (1) the area that is required to include species that occur with very low frequencies and species that have very large territories; (2) the negative effects of isolation between subpopulations that do not occur within one natural area; (3) the negative effects of the surrounding agricultural or urban landscapes. It is not yet possible to determine standard minimum areas, but first estimates suggest that the maintenance of vascular plant species diversity requires at least 10 to 50 km2 . For the conservation of landscapes that include the complete original community assemblage, including top predators, we need 1000 to 10.000 km

Design and implementation of robust supraregional corridors

Reijnen, M.J.S.M., P.F.M. Opdam & C.C. Vos

In the recent Nature Policy Plan, the National Ecological Network of The Netherlands was extended with robust supraregional corridors. These corridors aim at a further increase of the spatial cohesion of nature areas at the ecosystem level to ensure sustainable conditions for biodiversity. To support the design and implementation of the robust corridors a set of ecological guidelines was developed. The demands of species to a functioning corridor form the basis and integration of these demands lead to a design of an ecosystem corridor. We distinguished 11 ecosystem types and considered 81 fauna species and 317 plant species. For practical reasons species with comparable demands to a functioning corridor were joined to so-called ‘ecoprofiles’. This resulted in 51 fauna ‘ecoprofiles’ and four plant ‘ecoprofiles’. To support the phase of implementation additional guidelines are given on how to find an effective route for the different ecosystem corridors in a robust corridor, what measures are needed when crossing human infrastructure and what are the possibilities for recreation and water management.

Dispersal problems in the National Ecological Network

Bakker, J.P., R.M. Bekker, W.A. Ozinga & M.F. Wallis de Vries

The main National Ecological Network (EHS) in the Netherlands was developed to enhance the possibility of survival of organisms in a fragmented landscape including small nature reserves by enlarging space for nature. We summarise our conclusions of the first ten years. The present EHS is too small for the maintenance of plant species depending on deep seepage water and for the self-regulation of animal species such as large herbivores. The present EHS does not provide stepping stones for organisms occurring in isolated characteristic habitats such as heathlands in contrasting habitats such as former agricultural areas. The present EHS does not provide enough efficiently connecting long-distance dispersal vectors, such as water and large herbivores, the 'moving ecological infrastructure'. The EHS cannot restore the buffercapacity of the soil and counteract atmospheric nitrogen deposition.

Phosphorus: obstacle for realising the National Ecological Network on former agricultural land?

Chardon, W.J. & F.P. Sival

Successful nature development on former agricultural soils, necessary for realising the National Ecological Network, requires a new approach. Due to a nutrient-rich soil caused by long-term fertilization history, soil tillage and lowering of the groundwater table, it is likely that only species will occur that are characteristic of a eutrophic environment. Here eutrophication is, besides nitrogen, a consequence of phosphorus accumulation in the soil. Phosphorous is a serious problem because it is, in contrast with nitrogen, less mobile and therefore accumulates easily in the soil. The common management practices to reduce eutrophication are for phosphorous less effective than for nitrogen. Further research on management practices is necessary for creating environments suitable for vegetation under meso- and oligotrophic conditions.

New nature in an old landscape

Renes, J.

During the 1990s, growing areas have been taken out of agricultural production, to be converted into semi-natural ecosystems (‘new nature’). Although this process enlarges the ecological values of landscapes, it can work negative on the historic landscape values of the cultural landscape in three ways. Firstly, sometimes the land is intensively redeveloped to maximize ecological potential, which can cause a loss of landscape features. Secondly, much of the new nature is financed by extensive excavation of gravel, sand or clay, thereby destroying the historic landscape. Thirdly, new nature is often part of a deal, in which agriculture gives up marginal lands, but in return claims the right to intensify further (with a loss of landscape features as a result) on neighboring lands. During the last decade, these problems have been most obvious in the riverine region of the Central-Netherlands. The author urges for more cooperation between ecologists and landscape historians in the planning of new nature.