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Filling in the Gaps: Sedimentation and Macroinvertebrate Populations in Headwater Streams. Ankit Rastogi, Sarah Emel & Brigette Jones. Importance of Aquatic Systems. Biodiversity Ecosystem Services Agriculture and industry Filtering of pollutants Fisheries
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Filling in the Gaps: Sedimentation and Macroinvertebrate Populations in Headwater Streams Ankit Rastogi, Sarah Emel & Brigette Jones
Importance of Aquatic Systems • Biodiversity • Ecosystem Services • Agriculture and industry • Filtering of pollutants • Fisheries • Flood control and climate stabilization • Recreation and Tourism • Anthropogenic Impacts on Sedimentation • Construction • Dams • Mining • Impervious Surfaces
Impacts of Sedimentation • Fine Sediment Particles • Increased turbidity • Decreased light penetration • Primary productivity • Clogging gills • Clogging feeding apparatuses • Interstitial Spaces • Decreased habitat heterogeneity • Increased embeddedness • Increased drift • Susceptibility to predation
Hypotheses • Results of increased sedimentation in rocky-bottomed headwater stream systems • Decreased • Total macroinvertebrate density • Species richness • Shredders • Increased • Drift • Filter feeders • Collector-gatherer feeders
Study Sites • Clay Brook and Hewes Brook • Upstream reference site • Downstream treatment site • Added sand
Sampling and Measurements • Discharge • Embeddedness • Invertebrate drift • Surber samples • Treatment and Reference • Initial • 3 days after treatment • 10 days after treatment
Classification and Calculations • Classified macroinvertebrates to the Family level • Except Oligachaetes • Calculated total density, functional feeding group density, and richness from Surber samples • Calculated drift density • Compared physical features of sites
Summary • In Clay, ↑in all FFG’s, particularly shredders • In Clay, ↑ total density, ↑ family richness • In Hewes, ↑ predators, ↓ shredders • In Hewes, ↑ embeddedness, ↑ total density, ↑ family richness
Limitations • Small sampling size • High Variablitiy • High Patchiness
Conclusions • Increases in sedimentation have strong effects, especially on species composition • Studies have shown decreases in density and family richness, while we have seen the opposite • More research should be done to determine the particular factors that cause either result.
Brad Taylor Craig Layne Amy Dawson Denise Steele Chelsea Wood Cayelan Carey The students of Aquatic Ecology, Fall 2005 Dartmouth College Special thanks to the Hanover area families who allowed us to perform this study on their land Acknowedgements