Small patches dominate the Natura 2000 network of protected areas in Europe

The Natura 2000 network for protected areas is one of Europes main tool to address the loss of Biodiversity. Voluntary commitments of all 27 Member States aim for an extension to 30% of the European land and sea area by 2030. Despite the substantial efforts towards improving declining species and habitats across the continent and the limited success in measured improvements of biodiversity trends in the protected areas, the potential issue of fragmentation and configuration of the documented Natura 2000 sites has not been analysed in depth. This study presents an analysis of the full Natura 2000 data set of terrestrial and marine protected areas in Europe, to which extent documented sites are split up into smaller fragments, how their spatial configuration and shape might mitigate or invite edge effects, and which edge effects might be expected based on the surrounding land cover and land use matrix. Our results show a substantial fragmentation of the network, with four times more individual patches than recorded sites, and 75% of these patches being smaller than 1 km2. Across four size categories between smaller than 1 km2 and larger than 100 km2, about a quarter of patches show a spatial configuration that is likely to cause substantial edge effects due to a suboptimal ratio between area and perimeter. At the same time, many of the smallest patches are surrounded by a large share of sealed surfaces and agricultural areas within a 500m radius. Considering fragmentation and edge effects in future reporting, monitoring and planning of additional designations and restoration activities could close an important gap in understanding causes for continuing declines of Europes biodiversity and highlight pathways to mitigate them.