Trends in Distribution of Plains Minnow (Hybognathus placitus) in Kansas from 1964 to 2017

Abstract

Streams of North America have been degraded by over a century of anthropogenic stressors, including channelization, fragmentation, impoundment, dewatering, and the modification of the natural flow regime. These stressors have contributed to the decline of many freshwater fish species and are particularly detrimental to the pelagic-broadcast spawning reproductive guild of cyprinids. Members of this guild require an unfragmented river section of 458 (±137) river kilometers (rkm) in length to persist. The Plains Minnow is a member of this reproductive guild and is listed within Kansas as a threatened species. Plains Minnow were once common throughout Kansas, but have experienced declines in abundance and distribution. Using historical data and 14 y of new data, we analyzed the proportion of sites occupied by Plains Minnow over time within Kansas as a whole and within specific river basins using parametric linear regression models and nonparametric localized regression models. We found Plains Minnow to be declining within the historical range of the species across the state as a whole and specifically within the Smoky Hill-Saline and Lower Arkansas river basins. We found Plains Minnow distributions to be unchanging within the Kansas-Lower Republican and the Cimarron river basins. Within the Smoky Hill-Saline and the Kansas-Lower Republican river basins, the proportion of sites occupied by Plains Minnow has been at or near zero for the majority of the time period studied. Our findings support previously published studies and contribute to the growing body of evidence that Plains Minnow continue to decline within Kansas. If the species is to recover within the state, anthropogenic stressors will have to be mitigated, and repatriation efforts will need to be conducted.