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Communication at the NABS Annual meeting, Keystone, 2000
(25) LONGITUDINAL AND SEASONAL CHANGES IN BENTHIC MACROINVERTEBRATE COMMUNITY TROPHIC STRUCTURE ALONG THREE CENTRAL TEXAS STREAMS: SUBTROPICAL EXCEPTIONS TO THE RIVER CONTINUUM CONCEPT?.
B.R. Creutzburg and T.L.A. Arsuffi. Department of Biology--Aquatic Station, Southwest Texas State University, San Marcos, TX 78666
The River Continuum Concept (RCC) describes predictable changes in stream ecology along a longitudinal gradient. We hypothesized that due to dissimilar forcing functions than those described in RCC, streams in central Texas would differ markedly from the RCC’s model predictions. We determined the applicability of the RCC to streams in central Texas by examining the: 1) seasonal and longitudinal changes in functional feeding group composition of benthic macroinvertebrates along three river continua and 2) effects of recreation and a large spate. Results show that streams in central Texas have little seasonal variation. Recreational activities reduced macroinvertebrate communities in certain riffles by 1-2 orders of magnitude during summer. Furthermore, a 300-year flood event in October 1998 notably altered the distribution and abundance of many macroinvertebrates. Headwater functional feeding group composition differed markedly from RCC predictions, with collector-filterers dominating in 1st-2nd order streams. Our results suggest a need for further refinement of the RCC model to include subtropical streams with large source flows, poorly developed riparian areas and little seasonality.
Presented at 1:00 PM on Monday, May 29, 2000 in Spatial and Temporal Variation in Aquatic Communities I
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