Do you know where i can find info for the central heartland of north america ?

it should include info about the great and central plains .
climate
population
economy
vegetation
wildlife.

i cant find anything ,
please help ,
thank youu very much !

Here is a place to start:
http://en.wikipedia.org/wiki/Great_Plains
http://www.kansasheritage.org/prairie/
http://www.lib.ndsu.nodak.edu/govdocs/text/greatplains/text.html