Conservation of habitats is a major approach in the implementation of biodiversity conservation strategies. Because of limited resources and competing interests not all habitats can be conserved to the same extent and a prioritization is needed. One criterion for prioritization is the responsibility countries have for the protection of a particular habitat type. National responsibility reflects the effects the loss of a particular habitat type within the focal region (usually a country) has on the global persistence of that habitat type. Whereas the concept has been used already successfully for species, it has not yet been developed for habitats. Here we present such a method that is derived from similar approaches for species. We further investigated the usability of different biogeographic and environmental maps in our determination of national responsibilities for habitats. For Europe, several different maps exist, including (1) the Indicative European Map of Biogeographic Regions, (2) Udvardy’s biogeographic provinces, (3) WWF ecoregions, and (4) the environmental zones of Metzger et al. (2005). The latter is particularly promising, as the map of environmental zones has recently been extended to cover the whole world (Metzger et al. in press), allowing the application of our methodology at a global scale, making it highly comparable between countries and applicable across variable scales (e.g. regions, countries). Here, we determined the national responsibilities for 71 forest habitats. We further compared the national responsibility class distribution in regard to the use of different reference areas, geographical Europe, Western Palearctic and Palearctic. We found that the distributions of natural responsibility classes resembled each other largely for the different combinations of reference area and biogeographic map. The most common rank in all cases was the “medium” rank. Most notably, with increasing size of the reference area, a shift from allocations to a basic rank to allocations to a medium rank (from 1:4 to 1:1) was observed. The least frequent rank was the “very high” category. The methodology to determine national responsibilities presented here is readily applicable to estimate conservation responsibilities for habitats of the EU25 countries. It should be based on the environmental zones map and should use Europe as the reference area. It then provides a tool to allocate funds, direct conservation actions in the most sensible way, and highlight conservation-relevant data gaps.
