Fire, insects, and climate change in the Sawtooth Range, central Idaho

Investigation of insect remains in lake-sediments for developing a record of past insect outbreaksForest insects, such as bark beetles and defoliators, have existed with their tree hosts, probably for millennia. These insect populations have fluctuated in abundance through time and their impact on forests at any particular time seems to be regulated by weather, climate, and disturbance regimes. Although these species are present in most western forests in low numbers, bark beetles become extremely abundant and attack healthy mature trees during outbreaks, killing vast tracts of forested land. This study takes advantage of the unique opportunity offered in the Sawtooth National Recreation Area (SNRA) of central Idaho, where mountain pine beetle outbreaks are well documented for the last 50 years and where over 80% of the trees in large areas are currently dying from beetle attack. This study will provide a context for understanding current outbreaks, their ecological consequences, and their relation to other disturbances and climate change.

Long-term ecohydrologic variability in the Sawtooth region of central IdahoWater shortages can affect natural resources, disturbance regimes, recreational opportunities, and local livelihoods. The dramatic ecological manifestations of current drought in the SNRA are evident in the vast areas of beetle-killed forest, increased likelihood of catastrophic fires, and lowering of lake levels. Yet, the occurrence of such conditions in the past is poorly documented. This study is a collaborative effort between Dr. Whitlock and Dr. Pierce (Boise State University). High-resolution analysis of an 11,000 year lake core record will help determine the frequency of drought events and assess the ecological response to past droughts, in terms of fire, insect outbreaks, lake-level adjustments, and vegetation changes.