History Swims in the Chicago River too!

Here is an editorial from the New York Times on Feb 25th., that reflects a principle that we could use in Chicago:

History Swims in the Bronx

How clean can the Bronx River get? And how much biological diversity can such an urban river sustain? These are the questions posed by the recent appearance of a male beaver, lodge and all, in the Bronx. Unlike the manatee that swam up the Hudson last year — its species has never called New York home — beavers were synonymous with this city until they were trapped out 200 years ago. Like so many species, they display an extraordinary tolerance for the presence of humans, as long as humans are able to leave them alone.

One beaver and one lodge is not exactly a colony of beavers, nor does one beaver certify the health of the Bronx River. But such a pilgrimage downstream, from wherever this beaver originates, would have been impossible even a decade ago. The river then was choked with debris, and its waters looked more like sludge than anything potable. It has taken all this time — and some $15 million in federal money — to bring the river back. We will always be measuring the state of its health against the pollution of the 1970s and ’80s, and never against the river as it looked before European settlement. But the goal of guaranteeing the richest diversity compatible with human presence is what we should strive for, and the presence of this beaver is a sign of at least partial success.

The long-term prospects for a sizable beaver population in the Bronx are not great. The reason is not water quality. It is habitat. Beavers cannot make dams out of asphalt and concrete; they make them out of trees, preferably young ones. And until the forests of the Bronx return, we probably cannot hope for too much in the way of beavers. But then we may not have discovered yet just how adaptable Castor canadensis really is.