HR: 1330h
AN: NB33J-01    [Abstracts]
TI: Multiple Contaminant and Predatory Stressors in Experimental Pond Communities
AU: * Keeley, K
EM: kkeeley1@swarthmore.edu
AF: Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081 United States
AU: * Keeley, K
EM: kkeeley1@swarthmore.edu
AF: Blandy Experimental Farm, 400 Blandy Farm Lane, Boyce, VA 22620 United States
AU: Crumrine, P W
EM: crumrinepw@longwood.edu
AF: Blandy Experimental Farm, 400 Blandy Farm Lane, Boyce, VA 22620 United States
AU: Crumrine, P W
EM: crumrinepw@longwood.edu
AF: Department of Natural Sciences, Longwood University, 201 High Street, Farmville, VA 23909 United States
AU: Barlow, P F
EM: paige.barlow@richmond.edu
AF: Blandy Experimental Farm, 400 Blandy Farm Lane, Boyce, VA 22620 United States
AU: Barlow, P F
EM: paige.barlow@richmond.edu
AF: Department of Biology, University of Richmond, 28 Westhampton Way, Richmond, VA 23173 United States
AB: Anthropogenic contaminants, such as agricultural pesticides found in aquatic systems, have the potential to negatively impact organisms via direct and indirect pathways. The magnitude of these indirect effects depends on the strength of the interactions through which they are propagated. We sought to determine how environmentally realistic levels of the insecticides endosulfan and malathion and the herbicide atrazine impact pond communities. We investigated the effects of these pesticides in mesocosm communities containing larval dragonflies (Anax junius), adult water bugs (Belostoma flumineum), and snails (Planorbella trivolvis). Dragonflies presented a moderate predatory threat to snails, as they affected snail behavior but not survival. Direct effects of pesticides on snails were limited, and pesticides only induced modest changes in snail behavior. All pesticides negatively influenced dragonfly survival and this was most pronounced in treatments with endosulfan. However, the reduction in dragonfly survival did not transmit benefits to snails that were detectable as changes in behavior or survival, as would be expected if dragonflies represented a stronger predatory threat. These results show that individuals in communities can be differentially impacted by contaminants, and indicate that strong indirect effects depend on the strength of underlying trophic interactions.
DE: 9810 New fields (not classifiable under other headings)
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly