| As a rare remnant of unregulated Great Plains rivers, the Powder River is a hydrologically-dynamic system with wide-ranging flows that contribute to the maintenance of the physical environment and biological community. It has been hypothesized that steady inputs of water produced in association with coal bed natural gas development could alter the hydrologic dynamics and habitat conditions to which native fishes have adapted. This is a concern as the fish assemblage of the Powder River has been considered an ecological legacy. I conducted a suite of sampling and modeling analyses in order to make predictions as to how fish habitat and species occurrences could change with alterations of summer flows. Modeled incremental increases in summer flow suggested potential habitat effects, the most substantial being instability of shallow-water habitats believed to be critical for spawning and rearing of native fishes. Modeling further suggested that a wide range in flows is necessary to sustain Powder River fishes and that alteration in summer flows may affect both habitat and fish assemblages. Additionally, sampling of small-bodied fishes suggested that factors associated with invasive fish species may also be acting upon the native Powder River fish assemblage. |
