SAGE GROUSE DECLINES IN WESTERN NORTH AMERICA: WHAT ARE THE PROBLEMS?

摘要: Sage grouse (Centrocercus urophasianus) populations have declined throughout western North America. This species has been extirpated in 5 states and 1 province, all at the periphery ofthe original distribution. Breeding population size each of3 additional 2 provinces is estimated less than 2,000 individuals. Declines Colorado varied from 45 to 82% since 1980, depending upon area rangewide estimate least 30% decrease 1985. Major factors involved documented decreases distribution abundance are habitat loss (usually permanent), fragmentation degradation short term, 30 years). No single factor responsible for observed declines human-induced changes accentuated by periodic drought. natural undisturbed habitats known exist active management of sagebrush (Artemisia spp.) rangelands needed on a experiment basis.