19754

The idea of Pleistocene rewilding in North America is provocative, but it need not be treated only in the abstract. The return of beavers (Castor canadensis) to almost every region of the continent has shown us that the behavior of these creatures was, in many ways, originally responsible for the contours of the landscape and many rich soil deposits. Left to their own ways, beavers could reintroduce us to a North America that disappeared when they did.

James M. Bryant
Riverside, Calif.

The article presented an absolutely hair-raising scenario of potential ecological disaster. Introduction of plants or animals at a rate faster than can occur naturally causes a wave of parasitic inoculation that can rapidly devastate naïve local populations.