Texas freshwater fish assemblages following three decades of environmental change




Anderson AA; Hubbs C; Winemiller KO; Edwards RJ

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In 1953, C. Hubbs and colleagues surveyed fishes from a large number and variety of freshwater habitats throughout the state of Texas. Thirty-three years later, he replicated sampling at 129 of these sites within the Red, Sabine, Neches, Trinity, Brazos, Colorado, Guadeloupe, San Antonio, Nueces, and Rio Grande drainages. Care was taken to match original sampling effort, times, and dates at each location. Relative proportional abundances of families showed numerous changes from 1953 to 1986 within the ten basins. Mantel tests comparing family abundances in 1953 and 1986 datasets showed little overall change statewide. Sites in the eastern half of the state that did not contain marine species showed less significant positive covariation between early and recent datasets than those in western Texas. Rank plots of species diversity (H') for the two regions of the state showed a consistent trend of decreased diversity over time in eastern Texas. A similar plot for west Texas showed decreased diversity with time, but only within species-poor assemblages. The analyses reveal reductions in biological diversity on a local scale, but also reveal relative stability in statewide and regional ichthyofaunas. Despite the encouraging large-scale trends, several Texas fishes went extinct and others are threatened as a result of local habitat disturbances, including alteration of instream flow, eutrophication, and exotic species introductions




Biogeography: Population Studies; Conservation; Ecology: Environmental Sciences; Freshwater Ecology: Ecology,Environmental Sciences; Systematics and Taxonomy;ENDANGERED SPECIES; EUTROPHICATION; EXOTIC SPECIES; EXTINCTION;Pisces [Pisces];Pisces: Animals,Chordates,Fish,Nonhuman Vertebrates,Vertebrates;[00512] General biology - Conservation and resource management;[07508] Ecology: environmental biology - Animal;[07514] Ecology: environmental biology - Limnology;[62510] Chordata: general and systematic - Pisces;[62800] Animal distribution;[85200] Pisces;[85200] Pisces,Vertebrata,Chordata,Animalia;