Also, no cats, dogs, cows or sheep. Perhaps no house-mice or rats?<p><p>
I watched a documentary about the US National Parks (can't give a proper citation to it, but I guess some of the US readers here will have seen the same thing), which argued that they had been radically changed by the exclusion of resident people, whose influence had helped to define what nature was in those places for a very long time. So they implied that these places were artificial spaces, not really natural, just because people had been removed.<p><p>
Here (I'm British) our National Parks are different: they are just areas covered by extra planning law, and though rural, still have a lot of residents. The landscape is often defined by centuries of upland farming. If we photograph the plants and wildlife in these places, we definitely show a 'nature' as edited by human activity.<p><p>
I see a recent news article about a similar theory about the Amazon forest: http://www.bbc.co.uk/news/world-latin-america-39149334