The effects of human residential development on avian communities within Cottonwood forests along the Snake River riparian corridor in Jackson, Wyoming

Authors(s): C. Smith

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Publication Date: 0000-00-00

Type: annual report

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Abstract: Objectives As suburban development continues at a rapid rate in Jackson Hole, Wyoming, humans will have an increasingly significant impact on the wildlife of the area. At particular risk are the riparian corridors because they are attractive sites for homesite development. Several studies have been conducted to determine the effect of development on animals such as elk (Smith and Wachob, 2000) or coyotes (McClennan, 2000; Wigglesworth 2000). Little is known, however, about the effect of development on songbird breeding habitat in Jackson Hole. We propose to compare songbird communities and habitat use between the undeveloped Snake River riparian corridor in Grand Teton National Park (Moose, Wyoming to the southern border) and the adjacent developing area south of the park. We will use standard bird survey and vegetation sampling techniques and Geographic Information System technology to identify sampling sites. Our study design will stratify human landscape elements (e.g. houses, roads, etc.) and natural vegetation communities. We will measure songbird presence (number of species, individuals, species richness, diversity, etc.), vegetation characteristics (canopy cover, shrub density, dominant plant species, etc.), and human presence in the study area, with the goal of determining the influence of human development on songbird habitat use. Our findings will be of value to the conservation community and land managers by demonstrating how songbirds are impacted by human use of breeding habitat and will aid in creating ecologically sound land development practices. Findings and Status Preliminary Results: Data from last year's breeding season are curently being analyzed. Preliminary results of the effects of housing density (# of houses within 500m of bird point count sites) are as follows. All findings are significant at p<.05, determined by simple regression analysis. Bird species richness is negatively related to housing density. Control plots within GTNP and low density housing had significantly higher avian species richness. Bird diversity (calculated using the Shannon Diversity Index) was negatively related to housing density. Avian diversity was higher in GTNP and low density housing areas than in heavily developed areas of adjacent Teton County. Bird abundance was not related to housing density. Guild analysis of bird communities along the Snake River showed increases in generalists as housing densities increased (particularly Black-billed Magpies, Brewer's Blackbirds, Eurpoean Starlings, and Common Grackles). Insectivores, on the other hand, decreased with increasing housing densities. Additionally, as a guild, meotropical migrants decreased in relative representation as housing levels increased. Bird mist net data has shown significant (p<.05, chi-square analysis) differences between capture rates between the developed site and control plot in GTNP. On the whole, control plots for the study located within GTNP, showed a greater number of bird species, a more diverse avian community, and more specialized species than in contiguous developed areas located within Teton County, Wyoming. Further analysis is currently being conducted on the effects of housing densities on forest structure and landscape metrics (patch size, degree of isolation, etc.). This study will continue for the next two breeding seasons and results will be submitted for publication in peer-reviewed journals at that time.

Keywords: Jackson Hole, Grand Teton National Park, Teton County, breeding, population, management, Snake River, animal, bird, Aves, ornithology, human activity, suburban area, mammal, ungulate, elk, wapiti, Cervus elaphus, Cervidae, canine, Canidae, coyote, canis latrans, Black-billed Magpie, Pica pica, Corvidae, Brewer's Blackbird, Euphagus cyanocephalus, European Starling, Sturnus Vulgaris, Common Grackle, Quiscalus quiscula