Bioclimatic belts for the Mediterranean Basin as open access GIS layers

Abstract

Understanding how the distribution of terrestrial biodiversity and vegetation types relate to climate is a fundamental goal in ecology. Several bioclimatic systems have been developed to classify the life zones of the world. Among them, the global bioclimatic classification system by Rivas-Martínez allows to categorize the territory into bioclimatic belts according to climatic variables. This way, climatic continua are expressed as discrete categories that prove useful for inference about ecological communities and ecosystem functioning. However, the distribution of bioclimatic belts is not available either fully or in an unified way for the whole Mediterranean Basin, a biodiversity hotspot including a large bioclimatic breadth. To fill this information gap, we followed the rules of the global bioclimatic classification system of Rivas-Martínez and generated a bioclimatic belt map of the whole Mediterranean Basin at a resolution of 30 seconds (~1 km). We used the WorldClim temperature database and the R software as a Geographic Information System (GIS) to operate with the raster layers of interest (indices of positive temperature, continentality, thermicity, and compensated thermicity). The R code and resulting bioclimatic layers in vector and raster formats are available in an open access repository.