Recovery of Tundra Vegetation after Overgrazing by Caribou in Arctic Canada

During the summer of 1987, 500-1000 caribou became stranded on Rideout Island in Bathurst Inlet, Northwest Territories. The 40 sq/km island did not have sufficient forage to support the animals until freeze-up, and the caribou eventually died from malnutrition after severely overgrazing the vegetation. In late July 1988, we found that most of the vascular vegetation on Rideout Island had recovered considerably. Vascular species composition and cover in the two major plant communities were comparable to those in similar communities on the adjacent, moderately grazed mainland. The willows ( Salix spp.) and graminoid species were vigorous, and no differences were found in biomass allocation patterns of Salix lanata plants between the island and the mainland. However, essentially all of the macrolichen biomass was eliminated on the island, and full recovery could take more than 20 years. Key words: caribou, caribou range ecology, overgrazing, Bathurst Inlet, arctic vegetation, Salix spp., Betula spp.