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Predicting biotic community response to urbanization using high-resolution landuse/landcover data
Citation:
Morgan, J., N. Detenbeck, S. Rego, AND Y. Wang. Predicting biotic community response to urbanization using high-resolution landuse/landcover data. Association of American Geographers Annual Meeting, Chicago, IL, April 21 - 25, 2015.
Impact/Purpose:
Higher levels of impervious cover are associated with decreased water quality and quantity. High resolution estimates of impervious cover and riparian zone condition will contribute to more effective watershed management and regulatory processes.
Description:
Under EPA’s Green Infrastructure Initiative, research activities are underway to evaluate the effectiveness of green infrastructure in mitigating the effects of urbanization and stormwater impacts on stream biota and habitat. Preliminary analyses, using impervious cover estimates from the 30-meter resolution National Landcover Dataset (NLCD), have indicated that biotic communities are impacted at lower levels of watershed imperviousness than previously reported in the literature. It is likely that the NLCD data are underestimating impervious cover, particularly in suburban areas where impervious surfaces may be masked by tree cover. Concurrent analyses have found that the condition of forested buffer zones can help to mitigate the effects of urbanization, even when the natural functions of riparian zones are altered by stormwater drainage infrastructure. Higher resolution estimates of impervious cover and riparian zone condition may provide a more accurate depiction of stream response to urbanization. However, fine scale classifications are difficult at broad spatial extents. Methodologies were developed to improve classification accuracy using imagery from the National Agricultural Imagery Program (NAIP) program, LIDAR data, GIS, and genetic algorithms. An accuracy assessment was conducted and compared to classifications of previously established estimates from state and local high-resolution spatial data sets and evaluated along an urbanization gradient. These improved estimates were then used to re-evaluate biotic community threshold accuracy. This presentation focuses on watersheds in New England with high concentrations of green infrastructure and stormwater best management practices (BMPs), with the ultimate goal of evaluating the effects of aggregated BMPs on biological condition.