Thesis Title

Zooplankton Species Composition and Diversity in Floodplain Ponds: Effects of Flooding and Local Site Characteristics

Author

Kim A. Medley

Date of Graduation

Summer 2004

Degree

Master of Science in Biology

Department

Biology

Committee Chair

John Havel

Keywords

zooplankton, flooding, inundation, diversity, communities, ponds

Subject Categories

Biology

Abstract

Local environmental conditions and dispersal of colonists from the regional species pool together shape local communities. Physicochemical characteristics and biotic interactions influence local conditions and physical connection through flooding provides dispersal corridors for inundated pond communities. I explored crustacean zooplankton community composition and diversity in 29 floodplain ponds surrounding Truman Reservoir, Missouri. Topographic features and daily lake level data from 1993-2002 were used within a Geographic Information System (GIS) to determine flood frequency (0-59 events over 10 years) and flood duration (0-2603 of 3863 days) of the ponds. Spearman's rank correlations revealed negative relationships between both flood frequency and duration and species richness. In contrast, composition of pond communities was not visibly affected by these hydrologic factors. Local physicochemical variables were measured on one date and combined with flood frequency and duration in a community ordination (Canonical Correspondence Analysis). This analysis revealed strong relationships between species occurrences and presence of fish, pond depth, and distance from the lake. Species occurrences were mildly constrained by total dissolved solids (conductivity). Flood frequency and duration did not have a visible effect on community composition. These results indicate local environmental factors are more important in constraining community composition when dispersal is not limiting. However, when ponds are frequently disturbed by flooding, species richness is reduced.

Copyright

© Kim A. Medley

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Dissertation/Thesis

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