Extending Evaluations of Vegetation Response to Increases in Air Temperature across U.S. National Parks

Stemming from previous research efforts for the National Park Service and U.S. Environmental Protection Agency, E&S has expanded investigations into effects of expected increased air temperature on more than 1,000 understory plant species characteristic of vegetation communities within National Parks. Previously developed statistical models for each species were used in this project to model the effects of anticipated climate change and chronic exposure to air pollution (especially atmospheric nitrogen deposition). Vegetation communities within 168 National Park Management Units, including the Appalachian National Scenic Trail, Arches NP, Zion NP, and Redwood NP were included in the study. Preliminary results indicated that parks with the highest numbers of characteristic species expected to undergo more than a 95% decrease in occurrence probability under the +1.5 °C warming scenario were located in the southern and southeastern U.S. Species in parks located in the western and southwestern United States were generally the most sensitive to nitrogen deposition, with critical loads less than 5 kg N/ha/yr. Results from this work are planned for publication in the peer-reviewed literature.