Isolated wetlands are extensively drained and altered by urbanization, forestry and agriculture. These landscape changes could affect the suitability of wetlands as mosquito breeding habitat. Most mosquito surveillance is concentrated in urban areas, with little data available from agricultural areas of the southeastern U.S. The expansion of mosquito-borne disease has increased the need to determine how altered wetland conditions influence mosquito ecology. Larval mosquitoes were sampled weekly during an extreme drought from January 2011-June 2012, to determine how surrounding land use and environmental habitat factors (water chemistry, hydroperiod, and aquatic vegetation) influence larval mosquito assemblages in agricultural and reference wetlands typical of southwestern Georgia. Cluster Analysis was used to group wetland sites with similar land use and cover patterns in a 500m radius around each wetland, and an Indicator Species Analysis was used to test for associations among mosquito species and groups of wetland sites.
Results/Conclusions
Agricultural wetlands had longer hydroperiods, elevated pH levels, greater nitrogen, phosphorus and suspended sediments when compared to reference wetlands. For nearly all sample dates, larval mosquito abundance was greater in agricultural wetlands compared with reference wetlands. Preliminary results using an Indicator Species Analysis revealed that Anopheles quadrimaculatus, Culex salinarius, and Psorophora columbiae are indicators of sites dominated by row-crop agriculture and pasture land, Uranotaenia sapphirina is an indicator of sites dominated by pecan orchards, and Culex territans is an indicator of reference wetlands dominated by upland forest. These results suggest habitat preferences for some mosquito species in the region, which could make mosquitoes useful bioindicators of wetland condition. This research is also important in predicting potential arbovirus reservoirs at the landscape scale.