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Presented at the NABS Annual meeting, Vancouver, British Columbia, 2004
in Conservation Ecology 2
Constancy of riverine macroinvertebrate assemblages at Mammoth Cave National Park, Kentucky
S.A. Grubbs1, J.M. Taylor2, and G.J. Pond3. 1Department of Biology and Center for Biodiversity Studies, Western Kentucky University, Bowling Green, KY 42101, 2The Nature Conservancy, Dublin, OH 43017, 3Kentucky Division of Water, Frankfort, KY 40601
Persistence (qualitatively, as presence/absence) and stability (quantitatively, as relative abundance) can be defined as constancy or maintenance of species composition over time. Mammoth Cave National Park has established a Long-Term Ecological Monitoring (LTEM) along the mainstem Green River. The objective was to continue the Green River LTEM initiated in 1993-1995 through 2001-2002. Macroinvertebrates were sampled from seven common sites across three hydrologic zones using two artificial substrate samplers. Mean daily discharge was the only environmental data common to the two studies. Both persistence and stability were low, and this lack of constancy was reflected across local (site) and reach (hydrologic zone) spatial scales using both taxonomic-and metric-based analyses. Longer colonization periods of the 2001 and 2002 datasets and the less variable hydrologic regime for the 2002 summer period were implicated as two possible reasons for this discretion. Yet, whether the Green River flowing through MCNP has experienced nonconstancy according to any measure of assemblage structure remains unclear. Six datasets across nine years may insufficiently represent a time frame necessary to yield a representative oscillatory pattern. Current research is aimed at experimentation with colonization length to enhance comparability between 1993-1995 and 2001-2002 data.
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