I think the whole problem lies in the word environment and using subjective terms such as harm, benefit, etc. The environment is a neutral force.. what benefits one organism, might harm another. The is no universal "good" environment. While every other species does whatever provides them with the most benefit, we seem to hold our selves to a higher standard. The greatest good for the greatest amount of people....err creatures.
This is somewhat (I stress the somewhat) justified as our 'changes' to the environment have occurred rapidly while beavers have been building dams for thousands of years (allowing time for other species to adapt to those changes).