Grey Owl and The Beavers.

The story of Grey Owl is well worth reading if you can ever lay your hands on the book. The short story is that famers in this particular area were running out of water and green pasture mid summer. The reason for this was because all the beaver had been trapped out, and the beaver dams were no longer in place to flood upper pastures, and to retain water for the summer months! Some people just do not see how their actions effect the ballance of nature.
Grey Owl was responsible for the reintroduction of the beaver in this particular area.