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DTIC ADA323646: Annual Status Report, 1993: Macroinvertebrate Sampling |
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by Defense Technical Information Center |
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In 1992, macroinvertebrate sampling was initiated in |
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Pools 4, 8, 13, 26, and the Open River reach of the |
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Mississippi River, and La Grange Pool of the Illinois |
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River as part of the Long Term Resource Monitoring |
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Program. Long-term monitoring is needed to detect |
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population trends and local changes in aquatic |
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ecosystems. Mayflies (Ephemeridae), fingernail clams |
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(Sphaeriidae), and the exotic Corbicula species were |
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selected for monitoring. Midges (Chironomidae) were added |
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to the sampling design in 1993. Mayflies, fingernail |
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clams, and midges, members of the soft-substrate |
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community were chosen because they play an important |
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ecological role in the Upper Mississippi River System. |
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Sampling was based on a stratified random design and was |
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conducted at about 125 sites per study area. Mean |
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densities of organisms were weighted by strata for pool |
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or reachwide estimates. Pool 13 had the highest mean |
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number of mayflies (155 sq m), fingernail clams (2,596 sq |
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m), and midges (509 sq m ). The lowest mean number of |
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mayflies, fingernail clams, and midges (7, 1, and 10 sq |
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m, respectively) was encountered in Pool 26. Overall, the |
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impounded areas, including Lake Pepin, tended to support |
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the highest densities of mayflies, fingernail clams, and |
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midges. Substrates with predominantly a silt clay |
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constituent supported the highest mean densities of |
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mayflies, fingernail clams, and midges. |
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Date Published: 2018-04-05 02:21:59 |
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Identifier: DTIC_ADA323646 |
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Item Size: 28871148 |
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Language: english |
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Media Type: texts |
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# Topics |
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DTIC Archive; Sauer, Jennifer S.; GEO... |
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