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Forecasting the Effects of Climate Change on the Interactions of Native and Nonnative Salmonid: Robert Al-Chokhachy

Project Title: Forecasting the Effects of Climate Change on the Interactions of Native and Nonnative Salmonids
Mendenhall Fellow: Robert Al-Chokhachy, 406-994-7842,
Start Date:November 1, 2010
Education: Ph.D. (Aquatic Ecology), Utah State University, 2006
Research Advisors: Jeff Kershner (, Bob Gresswell (, Clint Muhlfeld (, Al Zale (Unit Leader, Montana Cooperative Fish and Wildlife Research Unit,, Molly Webb (U.S. Fish and Wildlife Service,
  Robert Al-Chokhachy

Project Description: Throughout the mountainous Western United States, native salmonids are an integral part of healthy ecosystems and have considerable societal and culture values. Most native inland salmonids, however, have experienced significant declines in distribution and abundance, and today many only exist in fragmented, small populations within headwater systems. In addition to habitat degradation and barriers to movement, non-native species have been identified as one of the major factors limiting native salmonids in the Western United States. 

Changes in temperature and precipitation patterns under global climate change are expected to expand the range of suitable habitat for non-natives within stream networks, resulting in significant increases in the distribution and abundance of non-natives. However, our understanding of how landscape attributes can affect local thermal and hydrologic patterns suggests that changes in global climate patterns will not translate evenly across large spatial scales. Robust assessments of how the range of suitable habitat for non-natives will shift in response to climate change will require downscaled (that is, watershed and regional) climate predictions that integrate local landscape processes and niche models describing conditions suitable for non-native species. Ultimately, integrating these two components will allow managers to prioritize where and when to implement non-native control measures to minimize or eliminate non-native interactions under global climate change.

Specific Objectives
Objective 1: Develop comprehensive review of non-native and native salmonid interactions.—Our initial objective will be to conduct a thorough literature review of previous research that has evaluated native and non-native salmonid interactions. This will be particularly relevant to (1) summarize which habitat factors (for example, temperature) result in successful non-native invasions; (2) understand how climate change may alter habitat and accelerate or even retard invasions due to specific life-history characteristics of non-native species (for example, spawning season); (3) improve our understanding of the impacts of non-natives on native salmonids; and (4) identify gaps in our current knowledge. 

Objective 2: Predicting impacts of climate change on non-native salmonids.—The second objective of this research will be to develop models to predict how climate change will affect the distribution and abundance of non-native salmonids (that is., brook trout, Salvelinus fontinalis; and rainbow trout, Oncorhynchus mykiss). Here we will focus our research on two regions in the Rocky Mountains, including the Flathead River Basin in northwestern Montana and the Boise River Basin in central Idaho. The availability of existing data and ecologically relevant differences in landscapes across these two basins will enable robust evaluations of potential differences in non-native expansions under future climate change and provide insight into the need for spatially explicit approaches for modeling these expansions across large spatial areas. 

Objective 3: Integration of models within existing conservation and restoration planning tools.—The results of this research will be integrated within an existing conservation and planning tool that is, decision support models; Climate Change and Native Salmonids Collaborative Research, to aid managers in making complex decisions under changing climate conditions. Our models describing how suitable habitat for non-natives will change spatially and temporally will enable managers to prioritize management actions. Quantifying current non-native distribution patterns with anticipated climate-induced changes in suitable habitat will allow for adaptive management strategies to minimize the impacts of non-natives in the future. For example, by integrating our results with ongoing native-species climate change research, managers will be able to identify where and when the placement of barriers to prevent non-native colonization will be effective while minimizing the effects to native species.

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Last modified: 16:08:25 Thu 13 Dec 2012