There is a lot of spatial environmental and land use and cover data layers for analysis at national and regional scale. But you need to know where to find it. On-line data portals like the FAO geonetworks are making it increasingly easy to find the data. Yet, much data and data sources are dispersed over the Internet and one has to spend time to find the best data available.
I have started to keep links relevant to my work in a table to make it easier to find it back later. It is not complete by any standards, and for sure will never by. But I will try to update it whenever I find the time / feel the need. I had published the table on my Ecodiv.org website before, but I though to make it more visible by publishing it here too (prompted by the new option to share Google docs on your WordPress blog)
For the full table, open it in my Google Docs. And if you know of any (spatial) data layer which you think is worthwhile sharing, please do so in the comments below: