Researchers find landscape features around reserves are key to increasing freshwater-reliant species diversity

The Birds and Habitats Directives are fundamental to Europe's nature conservation policy, with the Natura 2000 reserves covering 18% of the EU’s land area and more than 8% of its marine territory. The network aims to protect wild bird species, natural habitats and related rare, threatened or endemic species. However, despite ambitious targets and long-term efforts, biodiversity continues to decline, with 60% of the species protected under the directives continuing to be in an unfavourable conservation status, and 80–90% of floodplains degraded.

Much of the research literature indicates that river biota and river-related species are impacted by stressors at a larger scale – with catchment and upstream river-bank land use having a bigger impact than conditions within a protected area. However, the importance of the surrounding land outside Natura 2000 sites, and freshwater-related species richness inside the sites, has not yet been widely examined.

The methods applied in this research provide a good example on how to approach designing areas for species conservation, knowing that the wider area is an important consideration. Focusing on habitat conditions outside – as well as inside – existing protected areas, will aid effective conservation of freshwater-related species.

The findings of this study could help inform the identification of areas with a high potential for conservation and restoration, given the surrounding landscape setting. This research is pertinent, as a large number of additional protected areas will be designated under the EU Biodiversity Strategy for 2030, and the upcoming Nature restoration law.

The researchers selected 648 special areas of conservation (SACs) within Germany and containing at least 15% of freshwater-related habitat group types – i.e. running water, standing water, wet forest and grass wetland. Habitat conditions within the site were assessed: firstly, by calculating the area of freshwater habitat groups in the sites, secondly the average quality of all the river sections within each site, and lastly the average lake quality for each site – based on habitat surrounding the lake.

Finally, the researchers examined a 0.1-km and 1-km buffer of land surrounding each site, as well as a 5-km upstream area including 0.1 km on either side of the upstream river network. Seven land-use classes were distinguished: urban, cropland, pasture, forest, open (semi-) natural vegetation such as natural grasslands or ‘ruderal’ areas, and wetlands and waterbodies. The researchers calculated the percentage cover, diversity and patchiness in the different buffers for all seven land-use classes.

The conditions inside and outside the sites were statistically analysed alongside the occurrence of the selected species in these sites to establish any features that predicted biodiversity richness.

Freshwater-related species richness in this study was found to depend on land use in the area around each Natura 2000 site. The results showed that biodiversity (particularly birds) was higher in small Natura 2000 sites (less than 151.2 hectares) if the locations were embedded in a wet, diverse, and patchy landscape – due to the provision of additional habitats outside the sites. Given that most Natura 2000 sites in Europe are small, the surrounding habitat conditions and land use potentially influences and affects freshwater-related species in many Natura sites across Member States.

The researchers suggest that additional conservation and restoration areas, which may need to be designated in more intensively used landscapes to meet EU biodiversity targets, should be either large enough or surrounded by areas that are only extensively used, to ensure they efficiently protect freshwater-related species.

Source:

Kail, J., Januschke, K., and Hering, D. (2023) Freshwater-related species richness in Natura 2000 sites strongly depends on the surrounding land use besides local habitat conditions. Journal of Environmental Management 340: 118025.

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“Science for Environment Policy”: European Commission DG Environment News Alert Service, edited by the Science Communication Unit, The University of the West of England, Bristol.

Notes on content:

The contents and views included in Science for Environment Policy are based on independent, peer reviewed research and do not necessarily reflect the position of the European Commission. Please note that this article is a summary of only one study. Other studies may come to other conclusions.