Tuesday, May 27, 2008 - 11:15 AM
161

Evaluating the effects of hydrologic changes on stream macroinvertebrate assemblages in New Jersey pinelands streams

Jonathan G. Kennen1, Melissa L. Riskin1, and John F. Bunnell2. (1) New Jersey Water Science Center, U.S. Geological Survey, 810 Bear Tavern Rd., Suite 206, West Trenton, NJ 08628, (2) New Jersey Pinelands Commission, Science Office, P.O. Box 7, New Lisbon, NJ 08064

Water-supply development has been linked to changes in streamflow patterns, which can affect stream biodiversity. Relations of hydrologic, water-quality, and landscape parameters to stream macroinvertebrate-assemblages were evaluated at 43 Pinelands stream reaches as part of a multiagency cooperative effort. Nearly 3 years of daily flow data prior to and encapsulating the sampling period were generated using records from nearby indexed continuous streamflow gages. Macroinvertebrate samples were collected during low- and high-flow periods in 2004 and 2005. Corresponding data on water chemistry, physical conditions, and landscape configuration were collected. More than 170 flow parameters accounting for duration, frequency, magnitude, timing, and rate of change of flow events were calculated. Patterns in macroinvertebrate-assemblage structure among sites were examined using nonmetric multidimensional scaling (NMS) and general linear modeling (GLM) techniques. The primary NMS axis and indices of assemblage condition were significantly related to changes in flow regime (e.g., high- and low-flow duration, flashiness), instream habitat, and landscape alteration. GLM results are being used to identify hydrologic parameters associated with ecosystem disturbance, develop predictive flow-ecology response relations, assess withdrawal effects on assemblage structure, and provide water managers with a strong scientific basis for establishing targeted limits on hydrologic changes for maintaining aquatic health.


Web Page: hydrologic, assemblage-structure, GLM-techniques

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