Climate Change - Alpine Ecosystems Need a New Playbook
Contemporary climate change has re-written the rules of extinction. While some species may move upslope to beat the heat, their food sources or preferred habitats may not follow. With continued warming projected, conservation in alpine ecosystems requires a new approach. Pikas are an ideal species for evaluating possible conservation initiatives in this new paradigm because of their sensitivity to temperature, dependence on snow and year-round activity.
To understand pika habitat selection, we surveyed 211 sites on the Bridger-Teton National Forest, June -October 2010 and 2011. At each site we documented pika sign in a 12m fixed-radius plot. We also put out 40 pairs of surface/subsurface temperature loggers to examine the relationship between ambient and subterranean temperatures. Just because the above-ground air is warming, the temperature under the talus may remain cool.
We started our data analyses in March and wanted to share a few preliminary results. Forty-eight percent of our survey sites were occupied within the 12m plots. Occupancy rates were higher with increased detection distance from plot center (0-200m, 67% occupied). Important habitat factors included elevation, forage availability and rock size. Low elevation temperatures dipped below -10°C (a limiting cold threshold for pikas) during 10% of 9,138 hours logged. However, medium and high elevation temperatures were below -10°C during only 2-3%% of the time. We recorded zero hours in which temperatures exceeded 28°C, a proposed limiting heat threshold. Preliminary findings indicate that cold exposure and snow cover may be especially important in pika habitat selection. With continued temperature increases and low elevation snow depths predicted near zero by the end of the century, pikas and other alpine mammals will face increasing difficulty. Stay tuned for more information as we continue our research!
Wyoming Wildlife – The Foundation, 1% for the Tetons and a generous private donor have funded our work.
Photo provided by Jim Jacobson
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