Living on the Edge: Predicting Effects of Climate Change on Native Fishes in Northern Great Plains Streams

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Organisms that live in the semi-arid prairies in the Northern Great Plains are able to live through conditions of extreme heat, cold, floods, and drought. The fish that inhabit the warm, turbid waters of northern Great Plains streams are indicators of change in these delicate ecosystems, where water quantity and water quality are often precariously close to ecological tolerance limits. In fact, changes in water quantity associated with global climate change may transform some prairie streams from essential refuges to habitats no longer capable of supporting fishes. USGS researchers and their partners are studying these changes and developing tools to assist managers in predicting the effects of climate change on prairie stream ecosystems of the northern Great Plains.



  • Construct precipitation-runoff models to simulate daily streamflow for baseline (current) conditions in several watersheds in eastern Montana.
  • Develop a regional model of fish assemblage structure as a function of watershed characteristics using a database of over 1,600 fish collections from Montana prairie streams to serve as a baseline of current conditions.
  • Predict how hydrology and fish assemblages will be affected using the precipitation-runoff models and projected changes in precipitation and temperature from the RegCM3 regional climate model (available at
  • Use projected climate conditions to predict where changes in fish assemblages will occur, relative to the current levels of biological integrity (Index of Biotic Integrity or IBI) for the samples in the regional fish database. This will allow researchers to identify areas of primary conservation concern and compare them to the areas that are most likely to undergo changes as a result of climate change.