Vegetation Recovery Patterns Following Overgrazing by Reindeer on St. Matthew Island

Abstract

Heavy grazing by extremely high densities of reindeer (Rangifer tarandus) on St. Matthew Island in the Bering Sea resulted in degradation of the lichen stands. Grasses, sedges, and other vascular plants initially increased in response to the removal of lichens under heavy grazing pressure by the reindeer. Twenty-two years following the crash die-off of the reindeer, mosses had invaded large portions of the ground area denuded of lichens, and lichens had recovered to only 10% of the standing crop of living lichen biomass occurring on adjacent Hall Island where there is no history of grazing. Lichen species dominating the recovering lichen stands on St. Matthew Island were those of relatively low preference as forage by reindeer in contrast to those in climax lichen stands.