Multiscale Environmental Influences on Fish Assemblage Structure in Central Texas Streams

Abstract

We investigated the influences of local and landscape‐scale environmental variables on fish assemblage structure among 64 stream reaches in two large river basins in central Texas. The broad spatial extent of this study region provided an opportunity to examine fish assemblage–environment relationships at multiple scales across a range of stream types in landscapes exposed to varying degrees of anthropogenic alteration. We used nonmetric multidimensional scaling (NMS) combined with permutational analysis of variance, k‐means cluster analysis, and indicator species analysis to evaluate broad‐scale influences of ecoregional and large river basin boundaries on fish assemblage structure. We also estimated relationships between fish assemblage structure and environmental factors with NMS and rotational vector fitting across all ecoregions and within ecoregions. Ordinations of sites based on species composition grouped stream reaches together according to ecoregion, and k‐means clustering identified three groups that corresponded with ecoregional membership. Several species had high affinities with specific ecoregions, a pattern that tracked broad‐scale physiographic differences in climate, topography, terrestrial vegetation, and instream habitat. Within ecoregions, we observed that local‐scale stream habitat variables as well as larger‐scale landscape features were significantly related to fish assemblage composition. Substrate composition was a key local‐scale habitat factor, and a gradient of rocky substrate to predominance of mud and silt correlated strongly with assemblage structure within all three ecoregions. The abundance of instream woody debris was also an important local‐scale correlate for fish assemblage structure. At the landscape scale, patterns of agricultural and urban land development in the surrounding watersheds were consistently associated with fish assemblage structure in each ecoregion. This study adds important information toward a better understanding of how environmental factors structure fish assemblages across scales, which should facilitate refinement of existing habitat and biological indices for conservation of stream habitats and their biota.

Thermal Tolerance, Survival, and Recruitment of Cyprinids Exposed to Competition and Chronic Heat Stress in Experimental Streams

“…If we consider a stocking event to represent a scenario of stream drying and pool isolation, we would expect more Red Shiners to survive than Blacktail Shiners. Not surprisingly, the Red Shiner is one of the most widely distributed and abundant fish species in streams of the American Great Plains (Matthews 1986;MarshMatthews and Matthews 2000), and these fish have been shown to increase in abundance in response to both anthropogenic (Pease et al 2011) and hydrologic (Stanley et al 2012) stressors. Higher tolerance under temperature and competition stress is likely one of the factors contributing to the Red Shiner's high abundance and wide distribution.…”

“…Walters et al (2008) demonstrated that Red Shiner invasion success and hybridization with native Blacktail Shiners were positively related to turbidity, the extent of agriculture in the catchment, and low dissolved oxygen. Pease et al (2011) demonstrated that Red Shiners within the species' native range tended to be more abundant at sites with increased pasture (land cover) and mud-silt substrates caused by increased rates of sedimentation, whereas Blacktail Shiners were negatively correlated with these variables and were most abundant in streams that were situated in relatively undisturbed catchments. Red Shiners also increased in relative abundance after consecutive years of severe drought and flooding in central Texas streams (Stanley et al 2012).…”

The process domains concept as a framework for fish and mussel habitat in a coastal plain river of southeastern North America

“…The success of opportunistic, periodic, and equilibrium life history strategists have been shown to differ among drainage basins with differing hydrologic regimes or along the river continuum (Poff and Allan, 1995;Olden and Kennard, 2010;Mims and Olden, 2012). Previous studies demonstrate that variation in taxonomic and functional composition of fish communities in other streams draining the western gulf coast vary most strongly along the river continuum (Hoeinghaus et al, 2007;Pease et al, 2011). The extent of our study (i.e, the upper Neches River mainstem) did not encompass a substantial stream-size gradient and is likely the reason we did not detect strong differences in taxonomic or functional composition of fish communities among reaches.…”

Habitat associations of fish assemblages in the Cache River, Illinois

“…As a result of processes occurring at various and interacting scales, it has long been suggested to incorporate multiple spatial and temporal scales when analyzing community assembly (Poff 1997;Ricklefs 1987;Fausch et al 2002). Given the widespread influence of human activities at the landscape scale, different land uses and covers are commonly found to be associated with fish assemblages (Lammert and Allan 1999;Roth et al 1996;Stewart et al 2001;Allan et al 1997;Pease et al 2011). Agricultural land use, specifically, can have long-term effects on fish assemblages (Harding et al 1998).…”