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

The decline in abundance of the newly recognized Gunnison sage grouse (Centrocercus minimus) in southwestern Colorado is thought to be linked to loss and fragmentation of its habitat, sagebrush (Artemisia) vegetation. We documented changes in sagebrush-dominated areas between the 1950s and 1990s by comparing low level aerial photographs taken in these time periods. We documented a loss of 20% or 155,673 ha of sage brush-dominated areas in southwestern Colorado between 1958 and 1993. The amount of sagebrush-dominated area 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 obligates) may become extinct. Protecting the remaining habitat from further loss and fragmentation is paramount to the survival of this species.