..I'm overwhelmed by the ever-growing loads of data that's made available via the web. I.e., IUCN collects and hosts spatial species data which is free for download. I'm itching to play with all this data… And, in the end there may arise some valuable outcome:
In the below examples I made a map for amphibian species richness – without much effort. I used a 5×5 km grid (constant areas, provided by Statistik Austria) and amphibian species ranges and intersected this data to yield species numbers per grid-cell. For aggregation of the tables from the polygons produced by the intersection I needed to switch from ArcMap to R because ESRI's "Summary Statistics" only cover MIN, MAX, MEAN, FIRST/LAST… and there is no easy way to apply custom functions. So, I just accessed the dbf that I wanted to aggregate with R and did the calculations there.. then reloaded the layer in ArcMap and was done..