HR: 1330h
AN: B33E-27    [Abstracts]
TI: Influence of Ephemeral Sand Islands in a Large Prairie River on Diversity and Density of Benthic Macroinvertebrates.
AU: * Kreft, J M
EM: jkreft1@swarthmore.edu
AF: Swarthmore College, 500 College Ave., Swarthmore, PA 19081 United States
AU: Moore, S L
EM: slmoore@ku.edu
AF: Kansas Biological Survey, University of Kansas, Lawrence, KS 66047 United States
AU: Thorp, J H
EM: thorp@ku.edu
AF: Kansas Biological Survey, University of Kansas, Lawrence, KS 66047 United States
AB: The ecology of prairie rivers has rarely been investigated, with most aquatic studies focusing on reservoirs or intermittent streams. The Kansas River, a sand-bed river draining a watershed historically composed primarily of tallgrass and mixed grass prairie, contains in its channel numerous ephemeral sand-bar islands. Recent riverine research on relatively permanent, forested islands has shown a strong correlation between community attributes and hydrologic retention. However, our study examined potential relationships between the transitory slackwaters created by these ephemeral islands and the benthic macroinvertebrate community. We hypothesized that these slackwaters would contain greater species density and diversity than other parts of the river with higher current velocity. A total of 14 benthic habitats in 3 reaches were sampled with benthic cores in the summer of 2004. Density data confirm the importance of ephemeral slackwaters, with the highest total invertebrate densities occurring in low-velocity areas. Initial counts of chironomid midges, the dominant macroinvertebrate group, also support this conclusion, with greater diversity in areas of lower current velocity. Our results could help ensure the future health of grassland river ecosystems if the importance of ephemeral sand-bar islands and slackwaters are incorporated into future management plans.
DE: 4239 Limnology
DE: 4804 Benthic processes/benthos
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly