**5.2 Environmental data sets**

This step aims to obtain the environmental layers to be used. Usually, they must be on 'raster' format, in which a matrix of cells is used to build the image. Generally, a Geographic Information System (GIS) software is necessary, such as ArcGIS (ESRI Inc.) or DIVA GIS (LizardTech, Inc. and University of California) to prepare them for SDM. Climate data sets can be found in the WordClim (Hijmans et al., 2005) and in the International Center of Tropical Agriculture (CIAT) websites. Categorical data sets can be found in World Wild Life Fund (WWF) (Terrestrial Ecorregion - Olson et al., 2001) and Global Land Cover database (Bicheron et al., 2008).
