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INTERMITTENT AND PERENNIAL STREAM MACROINVERTEBRATE COMMUNITY RESPONSE TO IMPERVIOUS COVER: THRESHOLD INDICATOR TAXA ANALYSIS AND PERMUTATIONS
Citation:
Figary, S. AND N. Detenbeck. INTERMITTENT AND PERENNIAL STREAM MACROINVERTEBRATE COMMUNITY RESPONSE TO IMPERVIOUS COVER: THRESHOLD INDICATOR TAXA ANALYSIS AND PERMUTATIONS. Society for Freshwater Science (SFS) Annual Meeting, Detroit, MI, May 20 - 24, 2018.
Impact/Purpose:
Numerous studies have been conducted to examine the effectiveness of stormwater best management practices at the site scale but relatively little information is available concerning BMP effectiveness at the watershed scale. This study applies a powerful statistical approach to find thresholds of impairment for aquatic insect communities in streams along gradients of development and how those thresholds have shifted in response to improved management practices in the watershed.
Description:
The urban stream syndrome and the impact of impervious cover on macroinvertebrate communities is well-documented, but many exclude intermittent streams despite their prevalence. This study investigated macroinvertebrate communities of intermittent and perennial streams separately in the South Coast and Chaparral regions of California, USA. Macroinvertebrate data from Southern California Coastal Water Research Project and California Environmental Data Exchange Network were used in Threshold Indicator Taxa Analysis (TITAN) to determine macroinvertebrate community’s ecological thresholds and responses to impervious cover across the urban gradient. In a new approach to TITAN, statistical differences in thresholds along impervious cover gradients were determined by permuting observations 1) between intermittent and perennial streams, 2) during different weather regimes described by the Palmar Drought Severity Index, 3) between Chaparral and South Coast regions, both with Mediterranean climates, and 4) before and after implementation of the 2010 General Construction Permit in California that developed more stringent stormwater regulations for construction projects. Preliminary results indicated low ecological thresholds (<1% impervious cover) for both intermittent and perennial streams. Results from this study will be used to quantify the ecological influence of the California 2010 General Construction permit with future sampling.