M.S. (Master of Science)
Department of Biological Sciences
Stream ecology||Freshwater invertebrates
Colonization rates of macroinvertebrates on multiple plate samplers were observed at three sites on Mill Creek, Samplers were placed in the creek at staggered intervals and exposed for two, four, six, eight, and ten weeks with simultaneous removal of all samplers. Chemical and physical measurements were made every two weeks to correlate with colonization data. The mean number of organisms, number of taxa, and mean biomass were calculated for each sampling period. The dominant macroinvertebrate collected was the caddisfly, Cheumatopsyche. Cheumatopsyche colonized rapidly at Sites A and C, where the flowing water conditions created an erosional habitat, but was low in abundance at Site B, a pool area. Midge fly larvae colonized rapidly at Site B, as well as the mayfly nymph, Stenonema. Oligocheata were slow to colonize at Site B because of their preference for silt. After the samplers accumulated deposited silt, oligochaetes were the dominant organisms at Site B. Spatial differences were noted for all three sites on the creek with Site C having the highest number of organisms, taxa, and biomass (g). Site A had the next highest values and Site B had the lowest values. Site B had the highest taxonomic diversity (H) and evenness (J). At each site the highest diversity occurred after two weeks of exposure. No significant differences were noted in the number of taxa collected at any one site over the total study period except at Site A, where the two week exposure period was significantly different from the other exposure periods. No significant differences were noted in the number of organisms or biomass at any one site. Based on these observations, it is postulated that only four weeks of exposure in a creek are needed to obtain a stabilized community of macroinvertebrates.
Ehorn, Douglas Arthur, "Colonization rate of macroinvertebrates on multiple plate samplers at three ecologically different areas of Mill Creek" (1975). Graduate Research Theses & Dissertations. 1841.
iii, 81 pages
Northern Illinois University
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