GPP_Fig1

Project Contacts
Carl Saunders (EcoLogical)
Nick Bouwes (EcoLogical)
Carol Volk (South Fork Research)

Current Status
Production

Funding
ISEMP

Estimates of GPP can describe the productive potential of watersheds, which is an extremely important component of fish habitat.

ISEMP conducted a study to evaluate the feasibility of collecting information on Dissolved Oxygen (DO) to estimate gross primary production (GPP) and stream respiration at CHaMP sites. DO is a by-product of photosynthesis from primary producers (e.g. algae) during the daytime, while at night time all organisms are respiring and consuming oxygen. Therefore, differences between DO during different times of day can be used to estimate GPP. Data loggers were used to collect DO measurements at 24 CHaMP sites. CHaMP data (temperature, solar input, and conductivity, which is related nutrient availability) were then used to create a predictive model of GPP. Additionally, network scale information was used to estimate GPP across the stream network. We were able to predict GPP using data collected at the CHaMP sites (r2=0.53) and from globally available GIS data (r2=0.43) (Saunders et al. submitted). Also, GPP was highly correlated with both fish density in the fall and summer, as well as the estimated amount of consumption (Pval) to grow to the observed size during the season. Finally, the GPP network model was able to describe juvenile steelhead densities from snorkel counts at 200 reaches throughout the Middle Fork John Day. Further validation of the GPP model across a greater range of conductivities is necessary for more robust estimates. Also, because terrestrial invertebrates entrained in the drift are a large part of fish diets, a model approximating terrestrial inputs requires further development to fully describe food availability for salmonids.

In Progress

GPP estimates utilize conductivity, solar inputs, and stream temperature.  Stream temperature varies by year, and gross primary production estimates are generated for respective years.

Findings and Uses

Estimates of GPP can describe the productive potential of watersheds, which is an extremely important component of fish habitat.  This context is useful for managers to better understand and identify potential production limitations for salmon and steelhead.

GPP

GPP predictions from CHaMP survey data relationship to fall juvenilie steelhead density and summer juvenile steelhead density at tributary (black lines and symbols) or mainstem reaches (gray lines and symbols).  GPP was then predicted from network solar, conductivity and temperature data and related to steelhead densities.  The average proportion of maximum consumption to achieve observed growth of juvenile steelhead is shown in the lower right panel.

Products

Publications

Saunders, W. C., N. Bouwes, P. McHugh, C. Jordan. Submitted. A network model for primary production highlights linkages between riverine fish populations and autochthonous resources.  Ecological Applications.

Data

Coming soon!