Fish conservation in prairie rivers: Fragmentation and groundwater extraction

We document long-term changes in Kansas stream fish communities since 1950 in response to changes in the availability and fragmentation of stream habitat.  We compared streams in western Kansas, where groundwater extraction has dramatically altered flow regimes and reduced amounts of available habitat, to those in eastern Kansas, where flow regimes are less altered.  In both regions streams are highly fragmented by dams.  These modifications have results in a homogenization of fish communities.  Total species richness increased by up to 20 species in western Kansas streams due to invasions by cosmopolitan species adapted to lentic environments.  Species richness in eastern Kansas streams increased by 5 – 10 species.  Jaccard’s index of similarity between current fish communities and those present in the1950s, is less than 50% in western Kansas streams and > 80% in eastern Kansas streams.  Whereas species invasions are more prevalent in western Kansas, several prairie river specialists have decline in the entire region.  A number of native prairie fishes still occur in these highly modified systems, but projected changes in water withdrawals and impoundments continue to threaten their existence.