Characterizing predictive models of climate change and agricultural intensification on Oncorhynchus mykiss (steelhead) in the Umatilla River, Oregon, USA.

Authors: Laura E. McMullen, David Wooster, Sandy DeBano, Jesse Schwartz

Year: 2011 (xliii)

Abstract

The Umatilla River in the high desert of northeastern Oregon is home to populations of Chinook salmon (Oncorhynchus tshawytsha), coho salmon (Oncorhynchus kisutch), and summer steelhead (Oncorhynchus mykiss). This threatened river has experienced intense agricultural development that historically extirpated some salmonid species while severely reducing others. Measures were installed to restore salmonids, however future pressures from climate change and agricultural intensification may increase stress on the ecosystem and again challenge fish populations. Predicted effects of climate change in the region include temperature increases, increases in winter precipitation, increases in late fall and winter flow, and decreases in summer flow. Agricultural intensification is predicted to reduce the number of stream miles protected by riparian buffers. As part of a larger project examining how the Umatilla River drainage can be managed to support multiple ecosystem services under future pressures, we are using mathematical models to simulate stressor effects on steelhead populations. One approach we are using to predict effects of environmental changes on steelhead is EDT, or ‘Ecosystem Diagnosis and Treatment’. This is a species-specific, habitat-based model that relates environmental conditions to productivity and carrying capacity of life-stages, resulting in overall predictions of population productivity and capacity. Currently, we are parameterizing the model for alternate future scenarios. Results of this work will aid in long-term planning of Umatilla River management and protection of habitat for steelhead.