Event Title

Modeling Freshwater Mussel Distribution in Relation to Biotic and Abiotic Habitat Variables in the Middle Fork John Day River, Oregon

Presenter Information

Ericka Hegeman

Location

ECC 303

Event Website

http://water.usu.edu/

Start Date

4-3-2012 10:40 AM

End Date

4-3-2012 11:00 AM

Description

The habitat requirements of western freshwater mussels, Anodonta, Gonidea, and Margaritifera remain unclear despite their imperiled status. To improve the efficacy of restoration actions targeting these organisms, we used Random Forest modeling to investigate the biotic and abiotic factors influencing mussel density and distribution throughout a 55- kilometer segment of river. We collected data at both the reach and channel unit scale to investigate how mussel-habitat relationships vary with spatial scale. Margaritifera density exhibited a unimodal distribution while Anodonta and Gonidea density increased in a downstream direction. Model performance was greatest with Margaritifera at the reach scale, and reach scale models generally outperformed channel unit scale models. Physical habitat characteristics such as woody debris, emergent aquatic vegetation, substrate size, and channel shape generally had higher variable importance than hydraulic, biotic, and chemical variables. These results suggest that at the reach and channel unit scale, mussel abundance and distribution is influenced by high flow refugia and habitat heterogeneity. We anticipate that knowledge gained from this study will assist mussel restoration efforts by providing specific guidance about where suitable habitat may occur.

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Apr 3rd, 10:40 AM Apr 3rd, 11:00 AM

Modeling Freshwater Mussel Distribution in Relation to Biotic and Abiotic Habitat Variables in the Middle Fork John Day River, Oregon

ECC 303

The habitat requirements of western freshwater mussels, Anodonta, Gonidea, and Margaritifera remain unclear despite their imperiled status. To improve the efficacy of restoration actions targeting these organisms, we used Random Forest modeling to investigate the biotic and abiotic factors influencing mussel density and distribution throughout a 55- kilometer segment of river. We collected data at both the reach and channel unit scale to investigate how mussel-habitat relationships vary with spatial scale. Margaritifera density exhibited a unimodal distribution while Anodonta and Gonidea density increased in a downstream direction. Model performance was greatest with Margaritifera at the reach scale, and reach scale models generally outperformed channel unit scale models. Physical habitat characteristics such as woody debris, emergent aquatic vegetation, substrate size, and channel shape generally had higher variable importance than hydraulic, biotic, and chemical variables. These results suggest that at the reach and channel unit scale, mussel abundance and distribution is influenced by high flow refugia and habitat heterogeneity. We anticipate that knowledge gained from this study will assist mussel restoration efforts by providing specific guidance about where suitable habitat may occur.

https://digitalcommons.usu.edu/runoff/2012/AllAbstracts/2