Date of Award


Document Type


Degree Name

Master of Science



First Advisor

Dr. Roni Kingsley

Second Advisor

Dr. Michael Harrison

Third Advisor

Dr. Malcolm Hill


A survey of the Unionidae within the Pamunkey Watershed was conducted to investigate changes in distribution and species richness compared to a previous survey (Riddick, 1973) conducted over 30 years ago. Species richness decreased from 10 species in the previous survey to four species in the present survey. Notable increases of species richness were found in the upper South Anna and the lower North Anna regions, while sizable decreases were found in the lower South Anna and the upper and middle regions of the Pamunkey River. Regression analyses and t-tests comparing mussel survey data with habitat parameters were conducted to investigate the habitat characteristics most linked to unionid populations. The results indicated that greater composition of larger substrates and lower levels of silt deposition were significantly correlated to mussel presence. Crop land was the only quantified land use to correlate significantly (negatively) with changes in species richness and regional abundance parameters.

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