When you wrote "get started", I immediately thought of William Cronon's classic Changes in the Land. Even though it's pretty old, it's a great book on how the natural American landscape was changed by both the earliest immigrants ( Native Americans were perfectly happy to torch a forest to remove the underbrush and make hunting easier) and the later European ones. The knowledge of how the Native Americans changed things has been greatly enlarged since Cronon's book came out in 1983 ( Charles C Mann's 1491 is a very readable overview for some of that, though mostly about Latin and South America) but Cronon's major points about the commodification of the natural world by the Europeans still hold up very well.