Location: Water Quality and Ecology ResearchTitle: Ecoregional, catchment, and reach-scale environmental factors shape functional-trait structure of stream fish assemblages Author
Submitted to: Hydrobiologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/22/2015
Publication Date: 3/6/2015
Publication URL: http://handle.nal.usda.gov/10113/60752
Citation: Pease, A.A., Taylor, J.M., Winemiller, K.O., King, R.S. 2015. Ecoregional, catchment, and reach-scale environmental factors shape functional-trait structure of stream fish assemblages . Hydrobiologia. 753:265-283. DOI.org/10.1007/s10750-015-2235-z. Interpretive Summary: Water resource managers need better indicators for tracking health of freshwater ecosystems. Fish can be sensitive to changes in water quality and habitat, and may serve as good indicators of river health. We tested whether an approach that quantifies individual species requirements for whole fish communities was sensitive to changes in stream habitat across three different regions of Central Texas. We found that fish communities representing a wider range of habitat needs occupied streams with higher habitat quality, and within watersheds that have less agriculture and urban development. These results are important because they identify specific fish species traits that respond to stream habitat degradation. Future development of environmental measures based on fish that incorporate specific traits that are sensitive to alteration may provide more sensitive and broadly applicable indicators of river health.
Technical Abstract: Patterns of association between functional traits and environmental gradients can improve understanding of species assemblage structure from local to regional scales, and therefore may be useful for natural resource management. We measured functional traits related to trophic ecology, habitat use, and life-history strategies of fishes and examined their associations with environmental factors in the Brazos and Trinity River basins in Central Texas. We also examined the relationship between functional diversity of fish assemblages and indices of biotic integrity and habitat quality. Environmental characteristics at the local reach and catchment scales including the extent of forested area in the watershed, amount of land developed for urban and agricultural uses, stream size, substrate characteristics, and availability of riffle and pool habitats, were significantly associated with functional trait composition of fish assemblages. Broad physiographic differences between ecoregions also had a large influence on taxonomic and functional assemblage structure. In general, the volume of functional trait-space occupied by fish assemblages was greatest in streams with high habitat quality scores located within landscapes having less alteration from agriculture and urban development. Distributions of functional traits in fish assemblages might provide an additional basis for assessment of stream condition in relation to environmental impacts.