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Chapter 1
Evaluation of Relations Between Wildlife and Livestock Grazing and Water Quality

The national concern over non-point source pollution has stimulated research on the efficacy of current land management practices. In the west, specifically Wyoming, grazing by livestock and wild ungulates are major land uses. Because grazing is a source of non-point source pollution, much controversy has arisen among interest groups over the interaction of these two land uses on water quality (Phinney et al. 1989, Platts 1979). The debate has become more heated because of heightened concern over the degradation of riparian areas (Crouse 1989, Behnke 1977, and Armour et al. 1990).

Each state is required to develop best management practices (BMP) for each category of land use as part of its Non-point Source Management Plan (Wyoming Department of Environmental Quality 1989). A consideration in drafting BMPs for grazing is properly factoring the influences of wild ungulates when calculating the impacts of livestock densities on water quality. This consideration evaluates seasonal ranges of wild ungulates in both competitive and non-competitive situations. Natural and human induced densities of wildlife must also be considered. Determining wildlife influences on water quality over a multi-year period will provide necessary data for establishment of BMPs associated with grazing and for the control of non-point source pollution.

Unfortunately, the data available to correlate grazing practices with water quality are difficult to assess because livestock and wild ungulates commonly use the same areas (Thomas et al. 1978). For example, the tendency of cattle to concentrate in riparian areas that are also used by ungulates makes it difficult to assess the respective impacts. An associated problem is the influence livestock have on the behavior of wild ungulates, thus altering the impact of wild ungulates on water quality (Crumpacker 1981).

There are numerous reports that summarize impacts of livestock grazing on water quality, but very few address the impact of wild ungulates (Platts 1979a, 1982a). A thorough literature review was needed to provide information for the design of field studies that can measure the impacts of livestock and wildlife grazing on water quality and the relative contributions of each to the non-point water pollution problems in riparian habitats (Nelson and Peek 1981).

In this chapter four of the project objectives are addressed:

  1. Collect published and unpublished data on the impact of both livestock and wildlife grazing on water quality and riparian habitat.

  2. Determine if the data are sufficient to develop a predictive model that considers seasonal livestock animal unit months (AUMS) and wildlife herd levels for assessing the contribution of grazing to nonpoint source pollution.

  3. Summarize data on wildlife foraging behavior, seasonal movement, diel movement, winter feeding programs, and both natural and human-induced winter concentration of wildlife that might affect water quality.

  4. Compare foraging behavior of wildlife species in different riparian habitat types from available data to determine their relative influence on water quality.

Two methods were used to gather the pertinent published and unpublished literature for the data summarization aspect of this report. The published literature was identified from data base searches, including Fisheries Review, Wildlife Review, and Fish and Wildlife Reference Service of the U. S. Fish and Wildlife Service. The data bases of the Habitat and Technical Support (HATS) Division of the Wyoming Game and Fish Department and the Wyoming Water Bibliography of the Wyoming Water Research Center were also searched. The reference sections of these articles were reviewed to identify other pertinent articles. Articles were collected into a reference library and the information was abstracted onto computer files for summarization. Others have published reviews of grazing and riparian literature (Cuplin 1987, Thomas and Wentzell 1986, and U. S. Environmental Protection Agency 1979). These works were reviewed for pertinent articles.

The unpublished literature was obtained by soliciting professionals from federal and state agencies, societies, and other departments at the University of Wyoming for relevant information.

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