HR: 11:50h
AN: U52A-07    [Abstracts]
TI: Increasing Temperatures in Mountainous Regions of the Western United States and Effects on Insect Outbreaks
AU: * Hicke, J A
EM: jhicke@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Colorado State University, 1499 Campus Delivery, Fort Collins, CO 80523 United States
AU: Logan, J A
EM: jalogan@fs.fed.us
AF: USDA Forest Service, Rocky Mountain Research Station, Logan, UT 84321 United States
AU: Powell, J
EM: powell@math.usu.edu
AF: Department of Mathematics and Statistics, Utah State University, Logan, UT 84322 United States
AU: Ojima, D S
EM: dennis@nrel.colostate.edu
AF: Natural Resource Ecology Laboratory, Colorado State University, 1499 Campus Delivery, Fort Collins, CO 80523 United States
AB: Global temperatures have increased over the last 100 years and are projected to continue to rise as a result of greater atmospheric carbon dioxide concentrations. However, temperatures at high elevations are not uniformly increasing. Instead, trends vary regionally and depend on the time period of interest. Climate, specifically temperature, plays a major role in regulating outbreaks of bark beetles by synchronizing attacks on host trees during favorable temperature conditions. In this study, we characterize patterns of temperature change over the last 100 years for mountainous regions in the western United States, utilizing the VEMAP gridded database but also considering additional sources (e.g., SNOTEL, HCN). Although temperatures at higher elevations have changed little over the long term, recent decades have experienced warming. Projected temperatures in this region continue to warm through 2100. We explored the effects of changing temperatures on the spatial patterns of mountain pine beetle outbreak using a phenology model that predicts potential infestation. We show that temperature conditions suitable for outbreak existed in the past 100 years for most locations occupied by a favored host, lodgepole pine. At lower elevations, projected warming resulted in reductions in potential outbreak area. At higher elevations, potential outbreak area increased as temperatures became more favorable, then decreased as conditions became too warm to support synchrony of beetle attack. The shifts in climatically suitable conditions for mountain pine beetle outbreak have significant implications for lodgepole pine, a species dependent on disturbance, as well as other high-elevation pine ecosystems that are susceptible to infestation.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Union [U]
MN: 2004 AGU Fall Meeting