Using livestock grazing to improve habitat for Mountain Plovers: A summary of responses after 3 years of treatments

Authors: NEWBOLD, SCOTT - CA STATE UNIV-FULLERTON; STAPP, PAUL - CA STATE UNIV-FULLERTON; LEVENSAILOR, KATHERINE - CA STATE UNIV-FULLERTON; Derner, Justin; LAUENROTH, WILLIAM - COLORADO STATE UNIVERSITY

Submitted to: Shortgrass Steppe Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2007
Publication Date: 1/11/2007
Citation: Newbold, S.T., Stapp, P., Levensailor, K.E., Derner, J.D., Lauenroth, W.K. 2007. Using livestock grazing to improve habitat for Mountain Plovers: A summary of responses after 3 years of treatments. Shortgrass Steppe Symposium.

Interpretive Summary:

Technical Abstract: Livestock grazing is widely viewed as having negative effects on wildlife populations, but some species may benefit from habitat conditions produced by grazing, suggesting that under particular circumstances, grazing may be an effective habitat management tool. Mountain Plover (Charadrius montanus) is a species of conservation concern in the western U.S. that nests and rears chicks in areas with short grass cover and substantial amounts of bare ground. Cattle grazing may create preferred breeding habitat for Mountain Plover, but may also have indirect effects by altering the availability of insect prey or activity of small mammal nest predators. We began a large-scale, replicated experiment in 2003 to examine the responses of arthropods, small mammals, and nesting birds (as a surrogate for Mountain Plover) to five different treatments in an area of shortgrass steppe in northern Colorado where Mountain Plovers have been historically found. Experimental treatments (n = 4-6 0.81-ha plots per treatment) consisted of very intensive spring- and summer-cattle grazing, moderate summer cattle grazing (control), black-tailed prairie dog colonies within moderately-grazed pastures and long-term grazing exclosures (since 1939). We observed few differences in animal populations among treatments after two years (2005). However, in the third year of our study (2006), we are beginning to detect significant responses to treatments. As expected, exclosures supported distinct plant species and unique structural attributes. In addition, vegetation structure, but not species composition, differed between the control (moderate grazing) plots and the heavily spring-grazed plots. The heavily grazed plots were characterized by shorter grass and shrub stature, and fewer shrubs. Nesting birds seem to have responded strongly to these changes in habitat structure in 2006. Lark Buntings, which prefer more cover for nesting, tended to have fewer nests on the heavily grazed plots. In contrast, nests of Horned Larks, which prefer short grasses and bare ground (and represent a better surrogate for Mountain Plover), were more abundant on heavily grazed plots. Potential nest predators (grasshopper mice) were most abundant on prairie dog colonies, and tended to be less abundant on heavily grazed plots. We detected few differences across treatments among arthropods, but beetles tended to be more abundant on heavily spring-grazed plots in 2006. Collectively, our results suggest that heavily-grazed spring and summer treatments may create the most favorable conditions for Mountain Plover based on vegetation (short grass and shrub stature), nest predator (fewer), prey (more), and nesting bird (more Horned Lark nests) responses. Intriguingly, Mountain Plovers were only observed on prairie dog colonies in 2006. This suggests that even more intensive livestock grazing (in combination with prairie dog grazing) may be the most effective management approach for creating habitat suitable for Mountain Plover nesting. Alternatively, we may continue to see positive responses to the current treatments with time, suggesting we need only expand the time scale of our study, not the magnitude of the grazing treatments, to achieve habitat changes that are beneficial.