An investigation of wild ungulate impacts on landbirds and their upland aspen habitat in Jackson Hole, Wyoming.

Authors(s): S. Anderson and E. Anderson

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Publication Date: 0000-00-00

Type: annual report

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Abstract: The purpose of this study is to compare the consequences of varying densities of elk (Cervus elaphus) and other wild ungulates on 1) landbirds (i.e., smaller, upland-nesting, nongame species) in upland aspen communities and 2) habitat parameters within these aspen communities across Jackson Hole, WY. Recent studies indicate 1) wild ungulate browse-induced impacts on landbirds in this and other regions and 2) a decline in the condition of woody vegetation on the USFWS National Elk Refuge (NER). Fieldwork seasons include the summers of 2000 and 2001. We selected 34 upland aspen stands satisfying a suite of biotic and abiotic criteria, and their location across a broad spatial scale should permit inference into the consequences of browsing over a range of ungulate densities and management jurisdictions. The unique challenge of this study lies in establishing a link between ungulates and birds that may or may not share spatial scale, yet generally do not share temporal scale. To this end, in addition to comparisons of avian and habitat parameters among all stands (e.g. habitat use analyses) and among categories defined by management jurisdictions, comparisons will be made at multiple spatial scales and among categories of aspen stands defined by differential proximate evidence of ungulate use (e.g. twig-browsing and bark-stripping). Analyses underway include comparisons among these categories of, for instance, avian diversity and abundance by nesting guild, understory vegetation parameters, and rates of aspen regeneration and recruitment to overstory. We designed methodologies to provide insight into the cause of hypothesized aspen stand area decay and its incremental consequences on landbird species. Landscape-scale analyses will consider the role of aspen stand size, adjacent landscape composition and stand proximity to feed sites in structuring avian communities. Findings of this study will contribute to an EIS documenting the broader effects of the NER supplemental feeding program, as well as to the NER Comprehensive Conservation Plan required by the USFWS National Wildlife Refuge Improvement Act of 1997. The longevity, mobility and diversity of responses to environmental change characteristic of bird species provide motivation for the study of bird communities as early indicators of habitat decline impacting entire faunas.

Keywords: Wyoming Game and Fish, National Elk Refuge, Jackson Hole, Teton County, animal, ungulate, mammal, elk, wapiti, Cervus elaphus, Cervidae, Aves, bird, land bird, perching bird, passerine, ornithology, habitat, food , forage, population, management, deer , mule deer, Odocoileus hemionus, moose, Alces alces, nest, nesting, winter food supplementation, feeding