Pay attention to Canada: two interesting examples of art and ecology projects:
The Stanley Park Environmental Art Project in Vancouver which is comprehesively documented on the Vancouver City web site here including essays by Beth Carruthers and Kamala Todd with each artist interviewed by John K Grande. For images of ephemeral projects check this out. and semi-permanent works here. Apparently there is also youTube videos to come. John also interviewed Sharon Kallis about the Ivy Project here.