Impact of recent environmental change on Great Basin small mammals: An 80-year resurvey of the Ruby Mountains, Nevada

Background/Question/Methods

Understanding the current and future impacts of anthropogenic global warming and other drivers of environmental change on biotic systems requires a long-term perspective. This study uses historical museum data and modern field surveys to measure changes in the small mammal fauna of the Great Basin, one of the most threatened bioregions in North America. Using voucher specimens, detailed collector field notes, and photographs we reconstruct the ecological conditions 80 years ago at 16 sites in the Ruby Mountains, Nevada. Using comparable protocols we conduct modern field surveys to assess changes in community composition at local and landscape scales as well as shifts in the ranges of species along the elevation gradient.

Results/Conclusions

Preliminary data reveal strong signals of faunal change. At each local site there have been significant changes in relative abundance or occurrence, some in conjunction with major floristic changes, and others apparently in direct response to climate warming. At the landscape scale (along the elevation gradient), we document changes in the proportional abundance of mesic and xeric-adapted species, and upslope range shifts of mesic-adapted species that are consistent with predicted responses to climate warming. However, inconsistent with a climate-based hypothesis we show downslope range contractions in many xeric-adapted species which may reflect the unexpected predominance of habitat changes driven by land use at this broad spatial scale.