Response of black bears to gypsy moth infestation in Shenandoah National Park, Virginia

Abstract

The effects of gypsy moth infestation on the Shenandoah National Park (SNP) black bear population and habitat were studied during 1985 - 1991 by comparing radio telemetry, population, and behavioral data from preinfestation years (1982 - 1986) and years with extensive defoliation (1987 - 1991). Gypsy moth defoliation (> 60% canopy loss) increased from 546 ha in 1986 (1 % of the study area), to 2,304 ha in 1987 (4%), 6,227 ha in 1988 (12%), and 17,736 ha in 1989 (34%). Chestnut oak and red oak habitat types received the greatest defoliation; 60% and 45% of these habitat types suffered greater than 60 % canopy loss in the North and Central Districts, respectively. Infestation resulted in a 99% reduction in acorn production in defoliated stands. Maximum daily temperatures 0.5 m above the ground in defoliated stands averaged 4.7 ± 0.3 C, 4.3 ± 0.4 C, and 2.5 ± 0.3 C warmer (P < 0.01) than in nondefoliated stands during peak defoliation, refoliation, and post-refoliation periods, respectively. Bear