Cooperative Ecosystem Studies Unit, Rocky Mountain CESU

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The USGS Rocky Mountain Geographic Science Center (RMGSC) seeks to provide financial assistance for research investigating the effects of the native mountain pine beetle (MPB) and other disturbances on forested ecosystems in Colorado. Although the ongoing epidemic outbreak of MPB and its impacts have been quantified and studied in lodgepole pine (Pinus contorta) forests west of the Continental Divide, MPB populations are now also affecting or threatening different tree species, ecosystems, resources, and human communities and values. Specifically, forest managers and researchers are concerned about the potential impacts of MPB on ponderosa pine (Pinus ponderosa), a suitable host for MPB and a dominant tree species in lower-elevation forests east of the Divide. Ponderosa forests have had a long history of natural and anthropogenic disturbance (e.g. wild and prescribed fires, drought stress, logging) which may have affected their short-and long-term resilience to MPB attack. Although ponderosa pine is widely distributed in the eastern Front Range, a few isolated stands also exist on the west slope which may be particularly vulnerable to local extinction as they experience the combined effects of MPB, warming climate trends, and other disturbances. Little evidence exists from previous studies or experience to predict the probable impacts of MPB on ponderosa ecosystems, or to inform development of effective management and resource conservation strategies in light of projected climate change. For agencies such as the National Park Service, identification of the past disturbance history and probable future threats to isolated and/or rare populations of species on their lands is critical when planning ecosystem conservation or restoration actions. Research objectives The CESU recipient will conduct research that complements ongoing investigations of potential MPB impacts in the eastern Front Range by investigating the following questions: a) What is the current status and regeneration potential of rare ponderosa pine stands on the west slope of the Continental Divide, e.g. in Rocky Mountain National Park? b) Which disturbance events and/or trends appear to have affected the past population dynamics of west-slope ponderosa pine stands? c) How could current or future disturbance events (MPB-caused mortality; warming climate trends, etc) increase the vulnerability of these populations to local extinction? d) What are the implications of these findings for future ecosystem management options of these stands by Rocky Mountain National Park (and/or other resource managers)?

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