Biological Conservation (2012) 153: 227–238. doi: 10.1016/j.biocon.2012.04.031

We studied the spatial connectedness of Natura 2000 site boundaries and the functional connectivity of the Natura 2000 network across the 34 terrestrial borders of the European Union. Connectivity was measured by the dispersal success of 192 reptile, amphibian, invertebrate and plant species from Annex II of the European Union Habitats Directive, based on the presence of same species on both sides of the borders. Connectedness and connectivity varied greatly between state borders, with good and bad examples found in all parts of the European Union. Connectedness and connectivity were positively correlated. However, a few outlying examples showed that good connectedness is not necessarily associated with good connectivity and that good connectivity is not always possible because of different habitats and/or different management on both sides of border. In 13 out of 34 borders the connectivity measure was 100% and in 11 other borders it was over 50%. Very few of the geographical and political factors tested to explain variation in connectedness and connectivity were significant. Better connectedness and connectivity, both at the border and site-pair level, was correlated with the rivers forming the border. The time since the designation of the second site in a site-pair was nearly significant, suggesting that connectivity might have always existed in nature but the ‘documentation of it’ required some time for additional site inventories. It seems that each country border has its own history with a unique subset of factors influencing Natura 2000 site selection and management thus generalising our findings to other international borders would be difficult. We did not find substantial differences in trans-boundary connectivity among taxonomic groups. The application of our method elsewhere in the World would perhaps bring interesting results at a large (continental or sub-continental) scale, provided that similar data are available.

Connectedness and connectivity of the Natura 2000 network ... (ScienceDirect)