Analysis of Proposed Rock Quarrying and Trail Improvement Impacts on American Pikas in Grand Teton National Park.

摘要

This brief report provides an assessment of the potential impacts on the American pika (Ochotona princeps) population in Grand Teton National Park (GRTE) from a proposed trail improvement and rock removal effort near Jenny Lake. We used data collected in GRTE during 2010-2012 as part of the Pikas in Peril research project funded by the National Park Services climate change response program. The assessment was based on a specific scenario that was under consideration during winter 2012/2013 for removing rock from select locations to the west of Jenny Lake. Our assessment should not be interpreted out of this context, and cannot be used to infer impacts under different scenarios that may evolve over the course of the planning process. Under the proposed scenario, our results do not suggest that the proposed rock removal areas threaten pika populations locally or park-wide. However, they do imply a need for careful monitoring if the quarrying proceeds, given that 1) the impacts of such disturbance on pikas are not well understood; 2) the pikas in the area exhibit a unique genetic signature; 3) the area shows signs of isolation from other pika habitat; and 4) the affected area represents high quality habitat in an important, low elevation setting. We therefore encourage managers to minimize the intensity, duration and area of disturbance. We further recommend that the rate of territory abandonment and changes in population density be tracked as the quarrying proceeds. If feasible, it would also be useful to assess mortality rates during rock removal, as well as patterns of territory reestablishment for surviving pikas. Monitoring of pikas in GRTE using the NPS protocol (Jeffress et al. 2011) that is being used in other parks would provide this information over time. Ideally, pika surveys will be conducted in advance of quarrying to guide the final decisions about where quarrying should occur. Areas of particularly high concentrations of pika activity should be avoided.