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Thursday, June 7, 2007 - 9:30 AM
347
Urban vs. rural colonists—teasing out the patterns of wetland use by dragonflies on our urbanizing New England landscape
Maria A. Aliberti, Dept. Plant Science and Entomology, University of Rhode Island, Woodward Hall, 2nd Floor, Kingston, RI 02881 and Howard S. Ginsberg, PhD, Professor In Residence, USGS Pautexent Wildlife Research Center, Coastal Field Station, University of Rhode Island, Kingston, RI 02881.
Small wetlands play many roles in our urbanizing coastal landscape. The faunas of these wetlands are, in turn, influenced by factors related to the urbanization status of the site. The emerging dragonfly faunas of twenty-one small Rhode Island wetlands were surveyed over two field seasons (2004 and 2005) by standardized, timed collections of exuviae. These 21 sites are located along an urbanization gradient, indicated by chloride concentration and percent forest cover in a 100m buffer zone. No relationship was found between diversity measurements (species richness, Shannon-Wiener Index, etc.) and urbanization level. However, very different species assemblages predominated in urban vs. rural sites. Species assemblages also shifted with regard to distance from the coast, and presence of fish. We constructed a model of predicted dragonfly distribution patterns based on these results. Twenty-four new sites were surveyed in 2006 to test this model. Preliminary analyses suggest that overall patterns of species diversity at the test sites were compatible with predictions. Detailed analyses of species distribution patterns are ongoing.