HR: 14:15h
AN: NB13E-04 INVITED     [Abstracts]
TI: Response of Stream Macroinvertebrate Assemblages to Nutrients Within the Tiered Aquatic Life Use (TALU) Framework.
AU: * Back, J A
EM: Jeff_Back@Baylor.edu
AF: Center for Reservoir and Aquatic Systems Research, Department of Biology, Baylor University, One Bear Place #97388, Waco, TX 76798-7388 United States
AU: King, R S
EM: Ryan_S_King@Baylor.edu
AF: Center for Reservoir and Aquatic Systems Research, Department of Biology, Baylor University, One Bear Place #97388, Waco, TX 76798-7388 United States
AB: The US EPA's Tiered Aquatic Life Use (TALU) conceptual model uses narrative biological attributes to assign water bodies to tiers of biological condition. The model assumes that different types of biological attributes respond to increasing ecosystem degradation in a predictable manner. However, little empirical work has been done to evaluate whether attributes respond to specific types of stressors, such as nutrients, as predicted by the model. Thus, we evaluated the response of macroinvertebrate assemblage attributes to soluble reactive phosphorus (SRP) concentrations along a steep, longitudinal phosphorus gradient in the North Bosque River in central Texas. Consistent with the model, some attributes indicative of high biological integrity (e.g., percent intolerant taxa, percent EPT taxa) decreased with increasing SRP concentration. Similarly, some attribute values associated with poor conditions increased with increasing SRP concentrations. However, taxa richness peaked at intermediate SRP concentrations. Moreover, feeding group attributes, indicators of functional changes, showed no consistent pattern along the gradient. These results suggest that many of the theoretical responses to disturbance predicted by the TALU model may apply to nutrients in streams, but others may need additional scrutiny. They also demonstrate that macroinvertebrate assemblages may be useful in the development of numerical nutrient criteria.
DE: 4805 Biogeochemical cycles (1615)
DE: 4845 Nutrients and nutrient cycling
DE: 9902 NABS Student Award Applied Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly