Influence of changes in sagebrush on Gunnison sage grouse in southwestern Colorado.

The decline in abundance of the newly recognized Gunnison sage grouse (Cent rocercus minimus) in southwestern Colorado is thought to be linked to loss and fragmentation of its habitat, sagebrush (Artemisia) vegetation. We docu mented changes in sagebrush-dominated areas between the 1950s and 1990s by comparing low level aerial photographs taken in these time periods. We docu mented a loss of 20% or 155,673 ha of sage brush-dominated areas in southwe stern Colorado between 1958 and 1993. The amount of sagebrush-dominated are a was much higher and loss rates were much lower in the Gunnison Basin. We also found that 37% of plots sampled underwent substantial fragmentation of sagebrush vegetation. If current trends of habitat loss and fragmentation continue, Gunnison sage grouse (and perhaps other sagebrush-steppe obligate s) may become extinct. Protecting the remaining habitat from further loss a nd fragmentation is paramount to the survival of this species.