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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Large River Ecology
Response of aquatic macroinvertebrates to Environmental Pool Management and emergent vegetation in Mississippi River backwater wetlands
M.B. Flinn1, M.R. Whiles1, and S.R. Adams1,2. 1Department of Zoology, Southern Illinois University, Carbondale, Illinois, 62901-6501, 2Fisheries and Illinois Aquaculture Center, Southern Illinois University, Carbondale, Illinois, 62901
The influence of Environmental Pool Management (EPM) in Mississippi River Pool 25 was assessed during 2000 and 2001. Six 400 m2 vegetated and experimentally de–vegetated plots were established to examine benthic organic matter and macroinvertebrate responses. Three benthic cores (312 cm2) were collected in each plot during fall of each year. In 2000, there was no vegetation response because a proper water level drawdown could not be sustained, whereas in 2001 there was a strong vegetation response. In 2001, there was marginally higher total organic matter in vegetated plots (p<0.06), primarily because of differences in coarse material. During both years, there were no significant differences in total macroinvertebrate abundance and biomass between plot types. However, taxonomic differences were evident. For example, Dicrotendipes abundance (p<0.01) was significantly higher in the de–vegetated plots in 2001, whereas total Chironomidae (p<0.003), Chironomus (p<0.04), Cryptochironomus (p<0.02), and Polypedilum (p<0.01) abundances were significantly higher in vegetated plots (p<0.01). The non–insects Physa/Physella and Helobdella were also significantly more abundant in vegetated plots (p<0.05). Of functional groups, predator abundance (p<0.04) and biomass (p<0.05) were both significantly higher in vegetated plots. Results show that EPM and the associated vegetation responses influence benthic organic matter and macroinvertebrate communities.
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