The current and future potential maps for each species were overlapped using the spatial analyst tool of ArcGIS in order to produce a shift map. The shift map shows the overlapping areas that are potentially suitable for each species under the current and future climatic conditions. In this way it was possible to quantify the potential biorefugia areas where the species could survive if the predicted climatic change will occur.
The overlapping areas were intersected with the map of protected areas in order to quantify their contribution to the survival of each species. This procedure is known as “gap analysis” and it is useful to highlight eventual gaps in the actual network of protected areas with respect to climate change effects on plant species distribution.
According to these analyses Acer pseudoplatanus
, Acer obtusatum
and Carpinus orientalis
are the species with the smallest potential biorefugia areas and with the smallest biorefugia areas within the protected areas. Quercus frainetto, Ulmus minor
, Carpunus betulus
and Castanea sativa
have a relatively small protected biorefugia area despite their wider future potential distribution. The other species showed wider protected biorefugia areas so as to be considered more adapt to surveyed the predicted climate changes.