We present the results of a rapid assessment of butterfly diversity in the 754 ha Beaver Meadows study area in Rocky Mountain National Park, Larimer County, Colorado. We measured butterfly species richness and relative abundance as part of a landscape-scale investigation of diversity patterns involving several groups of organisms. A stratified random sampling design was used to include replication in both rare and common vegetation types. We recorded 49 butterfly species from the twenty-four 0.1 ha plots that were sampled four times during June, July, and August 1996. Butterfly species richness, diversity, and uniqueness were highest in quaking aspen (Populus tremuloides Michaux) groves and wet meadows, which occupy only a small proportion of the studied landscape. This result supports the suggestion that aspen areas represent ‘hotspots’ of biological diversity in this montane landscape. Patterns of butterfly species richness were positively correlated with total vascular plant species richness (r = 0.69; P < 0.001), and native plant species richness (r = 0.64; P < 0.001). However, exotic plant species richness (r = 0.70; P < 0.001) and the cover of exotic plant species (r = 0.70; P < 0.001) were the best predictors of butterfly species richness.
