Measuring Nitrogenous Air Pollutants at Upper Columbia Basin Network Parks, Idaho

Michael D. Bell*1, Edith B. Allen1,2 , James O. Sickman1,3, G. Darrel Jenerette1,2, Andrzej Bytnerowicz4 and Mark E. Fenn4

Anthropogenic nitrogen (N) emissions have been increasing in the Snake River Plains of southern Idaho due largely to agricultural sources, especially confined animal feeding operations and possibly a fertilizer factory. CMAQ (Community Multiscale Air Quality) model simulations show that the region has N deposition in excess of 10 kg ha-1 yr-1. Several National Park Service reserves and monuments are downwind of agricultural sources of reduced N, including Craters of the Moon National Monument and Reserve (CRMO), Hagerman Fossil Beds National Monument, Minidoka National Historic Site, and City of Rocks National Reserve. Highest levels of N deposition are modeled for BLM land near the town of Shoshone, and historic high levels are known from the region around a fertilizer factory in Pocatello. These high levels of N may be impacting the diverse native vegetation in sagebrush grassland, including some 700 species at CRMO alone. There is increasing evidence that N deposition may increase the invasion of non-native cheatgrass (Bromus tectorum), that is now found even in isolated and undisturbed areas of CRMO. The overall objective of this project is to evaluate the effects of atmospheric N deposition on the extent of cheatgrass invasion of the sagebrush steppe ecosystems of the Upper Columbia Basin Network monuments through a combination of field measurements of N inputs in bulk deposition collectors and passive samplers (both Ogawa samplers and Radiello samplers for comparative analyses), soil/plant N concentrations and stable isotope (15N) analyses, vegetation composition, and MODIS image analysis. The study is designed to provide feedback to regulatory agencies and land managers to help protect sensitive natural resources including biodiversity of sagebrush-steppe. We report on the first stage of this project, analyses from a network of passive samplers that were set up in June 2010 to determine air quality at 10 NPS, BLM, and university field sites.

*Corresponding author: Email: or ; phone: 951-827-2123
1Department of Botany and Plant Sciences, University of California Riverside
1,2Center for Conservation Biology
3Department of Environmental Sciences, University of California, Riverside, California 92521
4U.S. Forest Service Fire Laboratory, Riverside, California, 92507