Retrospective analysis of fish community change during a half-century of landuse and streamflow changes

摘要: Ecological thresholds that lead to alternative community states can be exceeded through gradual perturbation or as a result of sudden disturbance. Many Great Plains streams have experienced dramatic changes in their hydrologic regime resulting from water and landuse began early 1880. These changes, combined with the presence many invasive species, substantially altered fish communities this area. We quantified temporal 3 large river basins relation putative anthropogenic stressors, including increased sediment supply derived row-crop agriculture (beginning 1880), habitat fragmentation caused by reservoir construction 1950s), reduced discharge groundwater withdrawal 1960s). hypothesized these abiotic shifts, coupled species invasions, would shift system dominated lotic (flowing water) one lentic (still species. Further, we predicted timing intensity change vary across different types levels stressors. Restructuring was driven primarily similar increases only few declines several large-river Current share ,50% recorded historic collections, differences were extirpations invasions. The greatest divergence over time occurred western Kansas most intense withdrawals reservoirs. An alarming analysis recent (after 1991) expansion Arkansas lower River decline extirpation native where flow regimes are less heavily altered. Accelerating biota identified our retrospective highlight potential complications for restoring previous state.