HR: 08:45h
AN: NB21C-02 INVITED     [Abstracts]
TI: Midge Diversity and Bioassessment in the Everglades
AU: * Jacobsen, R E
EM: Pahayokeensis@aol.com
AF: Johnson Controls, Dan Beard Center 40001 State Road 9336, Homestead, FL 33034 United States
AB: Everglades midge community composition is strongly dependent upon hydroperiod (HP) and water quality. Longer HPs are generally associated with higher alpha diversity, species density, and total species richness. However, the development of extensive calcareous periphyton growth in marshes with 4-10 month HPs strongly influences community structure, and diversity and richness measures show no change along marl prairie HP gradients. Increases in species density with hydroperiod represent increases in habitat volume and productivity, not changes in community structure. Beta diversity is greatest when transitioning from marshes with 7-10 month HPs to those with >10 month HPs. At these HP lengths / water depths, plant communities that permit extensive periphyton growth are replaced by plant communities that inhibit periphyton growth, enable more organic soil development, and provide habitat for more specialized species. Point-source nutrient enrichment produces strong shifts in Everglades midge community composition, thereby increasing gamma diversity along nutrient gradients. Biologists studying invertebrate communities have reported either little structural change, or increases in species density, diversity and richness near sources of enrichment. I will report on midge community structural responses along a variety of nutrient gradients in the Everglades, and discuss important differences between pupal exuviae sampling and conventional larvae sampling.
DE: 1719 Hydrology
DE: 1803 Anthropogenic effects
DE: 1871 Surface water quality
DE: 1890 Wetlands
DE: 4804 Benthic processes/benthos
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly