HR: 1330h
AN: NB33B-02    [Abstracts]
TI: Rolling Stones: Studying Aquatic Invertebrates on Hard Rock Substrates
AU: * Testa, S
EM: stesta@msa-oxford.ars.usda.gov
AF: USDA Agricultural Research Service, National Sedimentation Laboratory PO Box 1157, Oxford, MS 38655 United States
AU: Cooper, C M
EM: ccooper@msa-oxford.ars.usda.gov
AF: USDA Agricultural Research Service, National Sedimentation Laboratory PO Box 1157, Oxford, MS 38655 United States
AB: Rock is an important habitat for aquatic insects and other invertebrates, but studying invertebrates on this substrate poses many potential problems to the ecologist. Rock is a common stream bed control material. Thus, land managers, for stream rehabilitation and erosion control/channel stability, are introducing rock to large numbers of streams, including many that previously did not contain this substrate. Two key impediments to study of rock-inhabiting invertebrates include accurate measurement of individual rock surface areas and calculating total available surface area for stream regions with overlapping layers of rock. We present an overview of concepts and methods used for study of rock-inhabiting invertebrates and provide information on new methods that enhance our ability to make easier realistic estimates. These new methods, especially one for calculating rock surface area based on weight or water displacement measurements of rocks, provide an accurate and efficient means for estimating invertebrate density. By combining recent methods to extrapolate invertebrate densities from individual rocks to estimates of total bottom densities of aquatic invertebrates for a reach or region of stream bottom area, we obtain much greater accuracy and precision in quantifying densities and estimating secondary production of rock-dwelling communities.
DE: 0400 Biogeosciences
DE: 1803 Anthropogenic effects
DE: 4211 Benthic boundary layers
DE: 4804 Benthic processes/benthos
DE: 5194 Instruments and techniques
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly