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Influence of Grazing on Biotic Crusts in a Central Washington Landscape
Completed
This project addresses one of the Bureau of Land Management's key research needs: Understanding the influence of grazing on the integrity of biotic soil crusts in semiarid rangelands. Grazing is planned to resume on parts of the Horse Heaven Hills near Richland, Washington based upon an Environmental Assessment (EA) by the Spokane District office of the BLM. This provides a unique opportunity to study cattle grazing effects in an area where the biotic crust is largely intact. We will conduct a thorough study of biotic crust communities before and after resumption of grazing, as well as in control areas. The local BLM office plans to monitor total crust cover and cover of nitrogen fixing species in a small number of plots. This is a rare opportunity in that it is such a large tract of high quality rangeland, some of which will be put into a permanent exclosure. Both pre-grazing sampling and the ungrazed allotment will provide excellent benchmarks for tracking any changes in the pastures. We have the opportunity to produce the a definitive account of the influence of a rest-rotation grazing system on biotic crusts in the northern Intermountain West. We hope to conduct a two-level field study: (1) Permanent plots with paired grazed/ungrazed comparisons at exclosures and fence lines and (2) Extensive stratified sampling with non-permanent plots. These data are necessary to provide a context for interpreting the results from the permanent plots in exclosures. We need to understand variation in the development of the biotic crust in relation to topographic position, historical disturbance, soils, and vascular vegetation. Sampling will be stratified by topographic position and pasture, such that each topographic position and pasture are sampled with equal effort.
Ponzetti, J., McCune, B., Pyke, D.A., 2007, Biotic soil crusts in relation to topography, cheatgrass and fire in the Columbia Basin, Washington: Bryologist, v. 110, no. 4, p. 706-722. [Highlight] [FullText] Catalog No: 1834 Ponzetti, J., McCune, B., 2001, Biotic soil crusts of Oregon's shrub steppe- Community composition in relation to soil chemistry, climate, and livestock activity: Bryologist, v. 104, no. 2, p. 212-225. [Abs] [FullText] Catalog No: 1105
Horse Heaven Hills Biotic Crusts - Landscape Strata
Horse Heaven Hills Biotic Crusts - Plot GIS Data
Horse Heaven Hills Biotic Crusts - Plot Locations
Horse Heaven Hills Biotic Crusts - Shade Shapefiles
Horse Heaven Hills Biotic Crusts - Wildfire Data
Horse Heaven Hills Biotic Crusts - Sagebrush Cover
Horse Heaven Hills Biotic Crusts - Curvature Grids
Horse Heaven Hills Biotic Crusts - Soils Data
Images of common tree species in western Washington
Pyke, David A. - Supervisory Research Ecologist
Phone: 541-750-7334
Email: david_a_pyke@usgs.gov
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