HR: 09:30h
AN: NB21C-05 INVITED     [Abstracts]
TI: Chironomid Size Distributions in Constructed and Natural Ponds: Responses to Land use and Water Quality
AU: * Haro, R J
EM: haro.roge@uwlax.edu
AF: River Studies Center, University of Wisconsin - La Crosse, 1725 State Street, La Crosse, WI 54601 United States
AU: Campbell, B D
EM: jaminben80@hotmail.com
AF: River Studies Center, University of Wisconsin - La Crosse, 1725 State Street, La Crosse, WI 54601 United States
AU: Richardson, W B
EM: William_Richardson@usgs.gov
AF: US Geological Survey, Upper Midwest Environmental Sciences Center, 2630 Fanta Reed Rd., La Crosse, WI 54603 United States
AB: Farm ponds in southeastern Minnesota are primarily constructed to prevent off-site soil erosion and to provide wildlife habitat in this predominantly agricultural landscape. Consequently, these ponds are subject to a variety of disturbances from agriculture, especially sedimentation and eutrophication. Natural ponds are rare and are located primarily at low elevations along tributaries to the Mississippi River. We examined chironomid richness, community structure and size-frequency distribution in response to a gradient of land use and water quality in 40 randomly selected ponds. Ponds were classified as natural or constructed; constructed ponds were further classified based on land use adjacent to the pond. Chironomid larvae and water quality were sampled 3 times in summer 2001. Chironomid generic richness significantly differed among pond type and community composition was strongly associated with adjacent land use. Size-frequency distributions were analyzed for the 10 most ubiquitous taxa: Polypedilum, Glyptotendipes, Chironomus, Tanytarsus, Procladius, Endochironomus, Ablabesmyia, Cricotopus, Dicrotendipes and Cladopelma. In general, slopes of normalized size-spectra for these taxa co-varied along the land use/water quality gradient. These results suggest that chironomid-body size may be a useful metric in biological assessments to evaluate the ecological integrity of constructed-pond ecosystems.
DE: 1815 Erosion and sedimentation
DE: 1890 Wetlands
DE: 4804 Benthic processes/benthos
DE: 4845 Nutrients and nutrient cycling
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly