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Benthic diatom composition in wet and dry isolated forested wetlands: implications for monitoring and assessment
Citation:
LANE, C. R., K. C. Reiss, SUSANNA J. DECELLES, AND M. T. Brown. Benthic diatom composition in wet and dry isolated forested wetlands: implications for monitoring and assessment. Presented at Society of Wetland Scientists Annual Conference, Washington, DC, May 25 - 30, 2008.
Impact/Purpose:
The EPA Office of Water has recognized a critical need for states and federal agencies to be able to quantitatively assess the condition of the Nation’s wetland resources. Currently, >85% of states, tribes, and territories are lacking even rudimentary biological assessment methodologies for wetlands. Additional important needs identified include obtaining base line nutrient and physical/chemical conditions to aid in understanding the role of wetland systems (isolated wetlands in particular) in ensuring aquatic life and beneficial uses of lakes, rivers, and streams in the watershed.
Description:
The development of bioindicators for wetlands, especially ephemerally hydrated depressional and isolated wetlands, can be problematic because of seasonal changes in hydrology and target organism biology. To determine if benthic diatoms could be used as a year-round biological indicator of wetland condition in isolated forested wetlands of Florida, eleven wetlands were sampled twice during a six-month period, once when hydrated and once when dry. Dry sites had significantly higher diatom taxa richness at genus and species levels. Non-metric multidimensional scaling and multiple response permutation process analyses resulted in no obvious or significant wet/dry grouping of abundance data. Five of seven metrics of the Florida Wetland Condition Index (FWCI) for depressional forested wetlands were significantly linearly correlated, while only one of seven metrics (a dissolved oxygen indicator) had a significantly different mean in paired t-test analyses. The final FWCI was significantly correlated betweenw et and dry sites, and no difference was found in mean FWCI score between wet and dry sites, suggesting that benthic diatoms can be used to monitor and assess wetland condition regardless of season or site hydrologic conditions.