Connectedness and connectivity of the Natura 2000 network of protected areas across country borders in the European Union

► Connectedness and connectivity of the protected area network across country borders was studied. ► Connectivity was measured by the presence of same species on both sides of the borders. ► Connectedness and connectivity varied greatly among borders and were positively correlated. ► Very few factors significantly affected variation in connectedness and connectivity. ► Each border has its own history and thus factors influencing selection of protected areas.