Environmental variables: how to download and process them with R

Georeferenced maps of environmental variables are currently essential for a range of ecological and biogeographical analyses, from species distribution and ecological niche models to global biodiversity trends. Such maps are now widely available in multiple online sources, although they often need to be processed to become compatible with each other and with the remaining data in the analysis (e.g. species occurrence or abundance).

In this short course, we will use a range of tools to

1) Import maps of climatic, topographic and anthropogenic variables from various sources into R (e.g. WorldClim, ENVIREM, CHELSA, AquaMaps, MARSPEC, Bio-ORACLE, SEDAC, CORINE)

2) Obtain the values of these variables for point locations (e.g. species occurrence sites, random background samples) and for polygons (e.g. grid cells, provinces and other spatial divisions

3) Try out different ways of converting categorical variables to continuous form, including proportions and distances

4) Adjust the spatial extent and resolution of different maps, so that they appropriately match each other as well as additional data in the analysis.

The course will be highly interactive and will include both theoretical and practical sessions. Participants are welcome to try working with variables of their own interest, although several illustrative examples will be provided too.