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MULTISTAGE CHARACTERIZATION OF RIPARIAN PATCHES IN THE ARID SOUTHWEST
Citation:
TallentHalsell, N G., E T. Slonecker, C M. Edmonds, AND T L. Roach. MULTISTAGE CHARACTERIZATION OF RIPARIAN PATCHES IN THE ARID SOUTHWEST. Presented at Annual Meeting of the Ecological Society of America, Spokane, WA, August 19, 1999.
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:
Some ecologically critical riparian ecosystems in the and Southwest are spatially and temporally discontinuous making their location and/or condition difficult to distinguish when studying the desert landscape. When conditions permit, riparian patches in the desert are distinct because they are more densely vegetated than the surrounding arid uplands. Discrete patches of green found on satellite imagery are often determined to be riparian ecosystems. However the presence or absence of these patches depends on what scale the landscape is being analyzed. Landsat Multispectral Scanner (60 m x 60 m resolution), Landsat Thematic Mapper (30 m x 30 m resolution) and airborne video data were analyzed in conjunction with ground observations to determine classification and characterization accuracy. A number of patch and landscape attributed were also analyzed. Error matrices (riparian patch omission and commission) were prepared which were then compared to ground observations. We concluded that many of the measures were sensitive to sensor resolution such as the number of riparian patches and percentage of water in the landscape decrease as grain size increases and that the decrease in resolution caused by pixel aggregation introduced more error. Such errors may influence the reliability of models of riparian response to hydrological alterations and livestock grazing being developed from such large-scale data.