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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Unionid Ecology
SMALL-SCALE ECOLOGICAL FUNCTION OF FRESHWATER MUSSELS (FAMILY: UNIONIDAE) IN THE KIAMICHI RIVER, OKLAHOMA.
D.E. Spooner and C.C. Vaughn. Oklahoma Biological Survey and Department of Zoology, University of Oklahoma, Norman, Oklahoma, USA 73019
There is a well-documented decline in biomass and species richness of freshwater mussels (Family Unionidae) in North America, namely as a result of recent and historic anthropogenic impacts. Currently, unionids represent a substantial part of the benthic biomass in some freshwater systems. Yet despite this marked trend, very little is known concerning the ecology of unionids with respect to ecosystem function and local macroinvertebrate assemblages. We performed a 12-month field enclosure experiment to examine the role of unionids in streams and document their associated sediment and epilithic communitites. Treatments were two mussel species, Actinonais ligamentina and Amblema plicata, shell treatment, and a non-mussel sediment treatment. We measured algae, ash-free dry mass and invertebrates in the sediment and on the shells over three time periods: 1 month, 3 months and 12 months. Chlorophyll a, AFDM and invertebrate abundance were higher in treatments containing live mussels. This trend was significant for months where flows were low, but non-significant during periods of high flow. However, there were no significant differences between species despite observed trends. This study indicates that unionids have the capacity to impact local algae, invertebrate and organic dynamics. However, this relationship appears to be context dependent and may be overriden by advective forces such as flow.
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