2.3.3. Environmental Variables

To build the ENMs for our taxa, we started from a set of 19 bioclimatic variables obtained from the WorldClim database vers. 2.0. (www.worldclim.org/current) [21]. We downloaded the bioclimatic variables in a consistent format (ESRI grid file) and resolution (2.5 min resolution, approximately 5 km grid cell sizes at the equator). Then, we converted all the bioclimatic variables in ASCII files and generated a Pearson's correlation matrix with SDMtoolbox (version 2.2) [46] in ArcGis (version 10.2.2; http://www.esri.com/software/arcgis). From the matrix, we selected only the variables for which r < 0.70 [47–49] in order to remove any variables that could be highly correlated with one another before developing the models. Pearson's correlation matrix led to a final set of 5 climatic variables: temperature seasonality (%), mean temperature of the wettest quarter (◦C), mean temperature of the driest quarter (◦C), precipitation of driest month (mm) and precipitation of coldest quarter (mm). We used these variables to carry out ENMs in current and in Last Glacial Maximum (LGM) scenarios.
