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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Wetlands II
USING BENTHIC DIATOM ASSEMBLAGES AS INDICATORS OF BIOINTEGRITY AND LAND USE CHANGE IN MICHIGAN WETLANDS.
L. Zheng and R.J. Stevenson. Department of Zoology, Michigan State University, East Lansing, Michigan, USA 48824
Sixty-seven wetlands across the low Michigan peninsula were selected along a human disturbance gradient to investigate the relation between wetland nutrients, land use and sediment diatom assemblages, and to develop indicators for wetland bioassessment. Water chemistry from fall 1994 and summer 1995 and sediment diatom assemblages from fall 1994 from sediment core samples were analyzed to develop diatom-based inference models. Four hundred diatom taxa were identified in the wetlands. Canonical correspondence analysis indicated that surface sediment diatom assemblages were correlated with conductivity and total phosphorus (TP) of both fall and summer water samples. The first two CCA axes of fall, summer and their averaged environmental variables explained 11.4%, 15.1% and 14.6% variation of species data, respectively, suggesting that sediment diatom assemblages are better indicators of long-term environmental conditions than water chemistry in wetlands. A subset of 37 palustrine wetlands was selected for CCA analyses and the first two axes explain 21.1% of the variance. Weighted average predictive models were developed for conductivity and TP and the results indicated that predicted values were highly correlated with measured average chemistry values. In addition, shifts in diatom assemblages of paleological and present samples were correlated with land use change and human disturbance.
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