Current Relevant Potential Living Areas (ARPL) maps of European and Flemish priority species

In a previous project, so-called potential habitats maps were made for a number of European and Flemish priority species (Maes et al., 2019). We used the so-called GeoDynamiX toolbox of the Flemish Institute for Technological Research (VITO). With the help of all kinds of available map layers such as the Biological Assessment Map, the soil map, the water surface map, etc. and detailed knowledge about the specific ecological requirements of each species, this model produces very detailed maps with locations where these species could potentially occur in Flanders (https://geo.inbo.be/potleefgebieden/). However, this did not take into account the current spread of the species and also defined areas where the species is not presently present or which are currently unreachable for the species. As a result, for some species rather large areas were identified as potentially suitable habitat and these maps could not always be used for policy purposes. To remedy this, we refined the potential habitat maps with up-to-date distribution information of the species by drawing a buffer corresponding to their colonisation capacity around the sites where they currently occur. By examining which potential habitats overlap with their current spread (including the colonisation buffer), we obtained maps with the so-called Actual Relevant Potential Living Area (ARPL; Maes et al., 2016). These maps therefore contain, on the one hand, all the areas where species currently occur, but also the potential habitats that can be reached by the species from these sites. This makes it a more practical tool in a variety of policy applications than the broad potential habitat maps. Through a collaboration between INBO and ANB, these ARPL maps have recently been available as a web service and can also be downloaded for use in GIS applications.