If you have any interest in the full document, let me know and I can email it to you. Would love to have as many eyes on this as possible. The same people have been editing it for three months now and I think they've gotten tired of reading it! (So don't be afraid to point out mistakes, or anything that doesn't make sense, etc).
Grass height and shrubs, especially sage-brush, are important to the greater sage-grouse habitat. Grazing is hypothesized to impact sage-grouse populations by reducing the height of herbaceous cover. This would have an impact on important sage-grouse breeding sites and the successfulness of their nests. This proposed research will test this hypothesis. Using exclosures and vegetation canopy surveys, this study will determine the amount of herbivory by horses on sage-grouse leks in southeastern, Oregon on the Riddle Mountain Herd Management Area. It will be concluded how much impact horse grazing has on sage-grouse nesting habitat.
This study will benefit the BLM in Oregon by providing needed field research on the sage-grouse habitat located in the Riddle Mountain herd management area (HMA). Here, the appropriate management level (AML) for this 28,000 acre HMA, determined by the BLM based on forage availability, is 33-56 horses (BLM, 2011.). As of my last conversation with the Burns District Rangeland Specialist, William Andersen, there were about 50 head of excess horses in the Riddle Mountain HMA (Andersen, Personal Communication, December 28, 2010, BLM, 2011). According to the recent Oregon Fish and Wildlife draft plan to maintain and enhance sage-grouse habitat, federal agencies are strongly encouraged to prioritize round-ups in horse areas that are both above AML and include known populations of sage-grouse (Hagen, Anthony, & Oregon 2010).
Beever, E. A. and Aldridge, Cameron L. (In Press.) Influences of Free-roaming equids on sagebrush ecosystems with focus on greater sage-grouse. Studies in Avian Biology.