Spatiotemporal dynamics of habitat productivity across a watershed habitat mosaic: implications for juvenile Pacific salmon

Freshwater habitat productivity contributes to the growth, survival, and life history diversity of fish. While habitat productivity likely varies through space and time across watersheds, few studies have investigated these dynamics. To address this gap, we described patterns of ecosystem metabolism and food availability through space and time in tributary streams and floodplain wetlands of the North Thompson watershed (British Columbia, Canada), which supports a threatened population of coho salmon (Oncorhynchus kisutch). We found diverse ecosystem metabolism regimes (gross primary production and ecosystem respiration) for streams and wetlands, but did not identify specific drivers of asynchrony. By contrast, we found striking seasonal differences in the magnitude and timing of food availability (invertebrate prey abundance, quality, and accessibility) between streams and wetlands. Collectively, these results suggest that seasonal variation in habitat productivity contributes to a portfolio of growth opportunities for juvenile coho salmon across the North Thompson watershed habitat mosaic.