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GRAZING POTENTIAL INDEX (GPI) AND SURFACE WATER QUALITY IN THE STATE OF OREGON: I. LIKELIHOOD OF ANIMAL PATHOGENIC PRESENCE USING ENTEROCOCCI
Citation:
NASH, M. S., T. G. WADE, D. T. HEGGEM, AND R. K. HALL. GRAZING POTENTIAL INDEX (GPI) AND SURFACE WATER QUALITY IN THE STATE OF OREGON: I. LIKELIHOOD OF ANIMAL PATHOGENIC PRESENCE USING ENTEROCOCCI. Presented at EPA 2005 Science Forum, Washington, DC, May 16, 2005.
Impact/Purpose:
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Description:
Cattle grazing is a widespread and persistent ecological stressor in the Western United States. Cattle impact surface water quality by introducing nutrients and bacteria and indirectly damaging stream banks or removing vegetation cover leading to increased sediment loads and increased temperatures. The objective of this study is to test the viability of grazing potential model developed with environmental data from the U .S. EP A Environmental Monitoring and Assessment Program (EMAP) to predict spatial distribution and concentration of animal borne bacteria (enterococci). From the Oregon EMAP project, sample sites with at least two years of measurements (197) were used for the analyses of enterococci. Of these sites, 25% (49 sites) exceeded the standard geometric mean concentration (35 cfu/100 ml). These sites were further investigated to identify trends over time (increasing/decreasing). Increasing or decreasing of the enterococci concentration at a site represents the impact of livestock presence or absence in the area. A total of 35 sites exhibited a positive or negative trend, only 13 sites had a significant positive trend and one site had .a significant negative trend. Further analyses are underway in investigating spatial distribution and relationship to landscape metrics (e.g. percent riparian cover, natural cover, etc.) and nitrogen and phosphorous loads to assess potential impacts to surface water quality from livestock grazing.