The national concern about water quality due to non-point sources of pollution caused by various land uses has encouraged widespread research on the efficacy of current land management practices. In the West, and specifically in Wyoming, both livestock grazing and wildlife foraging are widespread land uses, and the interactions of these two uses of land on water quality is the focus of heated controversy among interest groups (Phinney et al. 1989, Platts 1979). The controversy is amplified by concerns over the degradation of riparian zones and fisheries habitat (Crouse 1989, and Behnke 1977, Armour et al. 1990).
A major requirement of each state's Non-point Source Management Plan is the inclusion of best management practices (BMP) for each category of land use (Wilkinson and Anderson 1989). A consideration in drafting grazing BMP's relative to non-point source pollution is properly factoring the influences of native ungulate grazing when calculating the impact of livestock density on water quality. This consideration involves evaluation of the use of seasonal ranges by native ungulate species both in competitive and non-competitive situations. Determination of the influence of native wildlife on water quality over a several year period can provide much needed data for establishment of BMP's associated with grazing and for the control of non-point source pollution.
The types of data available to correlate grazing practices with different land use practices are difficult to assess because wild ungulate grazing and livestock grazing usually occur in the same area (Thomas et al. 1978). Thus, the individual impact of one or the other cannot be separated. Coupled with this problem is the fact that livestock grazing may influence the behavior of wild ungulates, thereby altering the impact of wild ungulates on water quality (Crumpacker 1981). Seasonal concentrations of wildlife associated with changing weather patterns may also alter the impact of wildlife grazing on water quality.
GOALS AND OBJECTIVES
The goal of this project was to assimilate information that may be used to design research that will evaluate relations between wildlife and livestock grazing on water quality in Wyoming. We have summarized available literature and information on the impact of both livestock and wild ungulate grazing on water quality for the purpose of providing technical assistance to the Wyoming Department of Environmental Quality and the National Environmental Protection Agency. This information will be used to define quantitative relationships between ungulate and livestock grazing and water quality.
We assimilated information from both the published and unpublished literature that address the known impacts of grazing on water quality. This was done to identify gaps in current knowledge and to determine specific research needs.
Two sources of information were used, published literature and the experience of professional managers. Published literature was identified through two data bases available through the U.S. Fish and Wildlife Service and several data bases available through the University of Wyoming. Searches of all pertinent data bases were conducted using a suite of key words. Additionally, Wildlife and Fisheries Review was searched. Pertinent articles were collected into a reference library and the information in them was abstracted on computer files for summarization. Personnel from all State and Federal resource management agencies in Wyoming that have responsibility for natural resources were contacted. Pertinent information that they identified, such as file data or project reports, were collected and summarized. Both published and unpublished information was used to address objectives 1-4. Potential study sites were evaluated according to location, accessibility, willingness of management agency to permit research on the site, species of wild ungulates that utilize the site and the season of use, livestock grazing history, observed impacts on water quality caused by livestock or wild ungulate grazing, and size of the study area. Based on the literature review and evaluation of possible study sites, field experiments were designed to evaluate impacts of wildlife grazing on water quality.
ORGANIZATION OF REPORT
This report is organized into two chapters. Chapter 1 summarizes published and unpublished literature regarding the impact of livestock and wild ungulate grazing on riparian zones and water quality and addresses objectives 1-4. Species of domestic and wild ungulates that may be affecting water quality are identified and specific impacts that may be occurring are discussed. Chapter 2 involves the design of experiments and addresses Objectives 5 and 6. Applicable study designs to assess the relations between livestock and wildlife grazing and water quality are discussed. A description and rating of potential study sites is given for each site that we evaluated. Sites with the highest potential for research are identified.
92-02 Table of Contents
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