PW18 Field Biological Monitoring of Ecosystem Impairment
Exhibit Hall
8:00 AM - Wednesday
(PW284) Elevated conductivity and habitat degradation associated with impacts of urban runoff on benthic macroinvertebrate communities in Malibu Creek, California.
Luce, S.1, 2, Ambrose, R.2, Abramson, M.1, 1 Heal the Bay, Santa Monica, CA, USA2 University of California, Los Angeles, CA, USA
ABSTRACT- Benthic macroinvertebrates (BMI) were sampled in fall and spring in Malibu Creek and its tributaries. Diversity, sensitivity and proportions of functional feeding groups in the BMI communities were lower at sites impacted by urban runoff and at sites with elevated nutrients and conductivity. The percent of taxa belonging to the filterer group increased at impacted sites while the percent of taxa in the shredder group decreased at impacted sites. Multiple regressions of BMI community metrics with habitat variables indicated that embeddedness of the substrate, percent canopy cover, and conductivity in the water were the most important factors influencing the BMI community, and conductivity was the best predictor of benthic community decline. Results were compared to toxicity data for the creeks. All these environmental factors are affected by urbanization in the watershed. We discuss ecological and management implications of these results.
Key words: macroinvertebrate, urbanization, conductivity, stream