Local and Landscape Influences on Meadow Butterfly Communities in Northeastern Sierra Nevada

MASTERS THESIS: Conservation planning and ecological research aimed at understanding patterns of biological diversity have focused on determining which environmental factors influence populations and communities. While local environmental factors were long considered to be of central importance, and interest in landscape context surged in the 1970s following the development of the theory island biogeography. In this study, I examined the relative influence of both local and landscape factors on butterfly communities in montane meadows of northeastern California. I ask if local attributes of meadows are more important than landscape context in determining butterfly richness and abundance, and I also examine meadow specialist and generalist butterflies, as well as the most abundant individual butterfly species. The strongest patterns were related to three variables. A single landscape variable, the percent of sagebrush vegetation in the matrix surrounding meadows, was strongly and negatively related to total butterfly richness and abundance as well as estimated butterfly richness and the abundance of a meadow generalist butterfly, Pyrgus communis. A single local variable, cover of obligate wetland plants within meadows, was strongly and positively related to species richness and abundance of meadow specialist butterflies, and the abundance of a single meadow specialist species, Plebejus podarce. In addition, elevation was positively related to the abundance of two butterfly species, Speyeria mormonia and Colias eurytheme, and negatively related to the abundance of Coenonympha tullia ssp. ampelos and Satyrium behrii. In general, local factors explained more of the variation for butterfly variables than landscape factors. Further, the moisture and topographical gradients that influence meadow butterfly communities suggest that protecting both moist meadow habitats and surrounding matrix habitats are important for conserving this faunal group.