Sedimentological evidence of late holocene disturbance on the Wasatch Plateau, Utah, USA

In spruce/fir ecosystems in the intermountain west, fire, bark beetles and humans play important roles in shaping the modern landscape. Environmental indicators derived from lake sediments provide excellent opportunities to resolve understanding of forest disturbance processes and the corresponding changes in forest composition. The Wasatch Plateau, located in central Utah, experienced an epidemic spruce beetle outbreak during the 1980s and 1990s. In subalpine forests in Utah and Colorado, epidemic spruce beetle (Dendroctonus rufipennis Kirby) infestations are as ecologically significant as stand-replacing wildfire. In addition to the spruce beetle outbreak, the Wasatch Plateau was dramatically impacted by land use changes brought on by the pioneers as they arrived in the 1850s that were among the most adverse in western North America during the settlement period. Palynological evidence from Blue Lake provides an excellent opportunity to calibrate observable changes in species pollen ratios due to large scale disturbance events. This study uses preserved pollen, charcoal, and macrofossils to analyze changes in watershed vegetation structure, as well as loss on ignition and magnetic susceptibility, to assess changes in depositional composition. This research examines paleoecological records to understand the relationship between landscape scale disturbance events and ecological structure as it is reflected in the lacustrine sedimentary record.