PARENT SESSION
Poster Session 28: Avian Ecology
Thursday, August 11, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Role of prescribed fire in maintaining breeding bird diversity in ponderosa pine forests of the western United States.

Russell, Robin^{*,1, 2}, Saab, Victoria^{*,1, 2}, ¹ USDA-Forest Service, Bozeman, MT² Montana State University, Bozeman, MT

ABSTRACT- We are examining the role of fire in structuring breeding bird communities throughout the interior western United States at multiple locations, comprising the Birds and Burns Network. One aspect of our research is evaluating the effects of prescribed fire on songbird densities by using a Before-After-Control-Impact (BACI) design. Sixteen paired treatment and control units (each 300-400 ha in size) were chosen in ponderosa pine (Pinus ponderosa) dominated forests in seven western states. Songbird densities were quantified using point count surveys and distance-based sampling, and surveys were conducted one to two years prior to prescribed burning on control and treatment plots. Prescribed burning treatments have been completed on seven of the 16 paired units, and songbird surveys were conducted within one year of treatment. Program Distance was used to determine songbird densities for six species (Spizella passerine, Junco hyemalis, Myadestes townsendi, Sitta Canadensis, Poecile gambeli, Dendroica coronata) in the Northwest Region (Idaho and Washington), and six species (Poecile gambeli, Junco hyemalis, Dendroica graciae, Sitta carolinensis, Sialia mexicana, Sitta pygmaea) in the Southwest Region (Arizona and New Mexico) before and after prescribed burning. Due to the non-independence of density estimates, (densities estimated using the same detection function are not independent), we used bootstrapping techniques to estimate the variance of the densities. We quantified the magnitude and direction of the change in songbird densities due to prescribed fire treatments by calculating the difference between control and treatment units before and after burning, and determining whether the difference attributable to the burning was significantly different from zero. In the Southwest, J. hyemalis and S. mexicana exhibited strong positive responses to prescribed fire, whereas P. gambeli densities appeared to decline after burning. In the Northwest, the strongest responses were declines in P. gambeli, S. Canadensis, and D. coronata densities. This research will help us determine the mosaic of ecological conditions necessary to maintain the native avifauna of ponderosa pine ecosystems throughout North America.

Key words: distance sampling, songbird densities, Before-After-Control-Impact, Rocky Mountain region