"... are coming to terms with the idea that the historical remit of most parks systems — to preserve a piece of land in its 'natural' state — is untenable. 'You can't fight the climate,' says Ken Aho, an ecologist at Idaho State University in Pocatello, who studies non-native species at Yellowstone National Park in Wyoming. 'Eventually you have to throw up your hands,' he says."Aldo Leopold, author of A Sand County Almanac, and an influential pioneer of wildlife management in America, opined that "a national park should represent a vignette of primitive America." On the other hand, the very idea of an "untouched wilderness", as something apart from human civilization, and to which we should have recourse when we wish to seek Nature (with a capital N), is a recent invention.
It's an unrealistic idealization because there's really nothing that has escaped the human hand, being only a matter of degrees. Environmental historian William Cronon reflects on this in a thought-provoking 1995 essay entitled "The Trouble with Wilderness; or Getting Back to the Wrong Nature" (reprinted 2005 in Guernica magazine).
The concern about the fate of Yellowstone and other iconic American parks reminds me of a research talk I attended a long time ago; unfortunately I can't remember who gave it and when. It was about the gazetting of marine reserves, and the speaker pointed out that the fact of accelerated climate change meant that our intuitions about what to preserve are often wrong. Instead of drawing park boundaries only around the prominent patch of pristine reefs, which with rising temperatures and bleaching will eventually become an ugly dead zone, we should include in large part those areas which are less picture-perfect, but which contain communities which are more robust to change and which the future ecosystem will still rely upon.
The overall message is that we can no longer afford to think of nature as 'timeless', especially with the prospect of further anthropogenic change.