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ESR prepress abstract   -  DOI: https://doi.org/10.3354/esr01161

Seasonal consumption of terrestrial prey by a threatened stream fish is influenced by riparian vegetation

Jacob Burbank*, D. Andrew R. Drake, Michael Power

*Corresponding author:

ABSTRACT: The consumption of terrestrial prey by fishes highlights the functional value of terrestrial habitats, but such consumption is not well documented for many small-bodied species. We determined the diet and consumption of terrestrial prey by a threatened fish, Silver Shiner, Notropis photogenis, using stomach content and stable isotope analyses to better understand the functional role of riparian habitat for the species. We found Silver Shiner to be a generalist drift feeder that consumed a wide range of aquatic and terrestrial prey. Both stomach content and stable isotope analyses indicated that terrestrial prey was commonly exploited, and that terrestrial consumption was seasonally and spatially variable. The contribution of terrestrial prey to Silver Shiner diet based on stomach contents was, on average, 41.53 ± 32.35% in fall and 20.45 ± 20.45% in summer and based on stable isotopes was 35.24 ± 4.41% in fall and 39.88 ± 12.34% in summer. During fall, when bankside terrestrial invertebrates were more abundant, Silver Shiner stomachs contained significantly more terrestrial prey in reaches where riparian vegetation cover was highest, indicating that reaches with intact riparian cover may be important habitats for Silver Shiner by facilitating access to high quality prey. The consumption of terrestrial prey may be particularly important in fall as terrestrial prey may promote increased growth and survival leading to more successful overwintering. Findings here suggest that terrestrial subsidies are ecologically valuable for Silver Shiner, and that the protection of reaches with intact riparian habitats would likely improve conservation and recovery efforts by helping ensure access to key prey resources.