2022 Early Hearing Detection & Intervention Virtual Conference

March 13 - 15, 2022

6/05/2017 | 2:45 PM - 3:00 PM | GENERALIZABILITY OF STREAM FLOW EFFECTS: HOW STRONG IS SMALL-SCALE VARIATION? | 302C

GENERALIZABILITY OF STREAM FLOW EFFECTS: HOW STRONG IS SMALL-SCALE VARIATION?

How generalizable are relationships between stream flow variation and fish population dynamics? This a tricky question because flow effects can vary by species, season, local habitat and geography. It is also challenging because flow effects are quite difficult to estimate as we rarely observe the direct effects of flow on fish. We present results of modeling studies for two types of data on brook trout: widespread count data from many sites vs. long-term individual-based data from one intensively-studied site. With both data types we identified seasonal effects of flow variation on body growth and survival. Results were largely convergent, identifying negative effects of high winter flow on age-0 survival and negative effects of low summer flow. While these results appear robust, the PIT tag study also revealed that seasonal flow effects varied at small spatial scales across the stream network. In general, survival was much more sensitive to flow variation in the tributaries than in the mainstem. Our results suggest that the search for generality in flow responses needs to consider life stage, season and stream order.

C02 Fish and Other Aquatic Vertebrates
C15 Population Ecology
S31 Moving forward in flow ecology: identifying and testing key hypotheses

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Presenters/Authors

Ben Letcher (), U.S. Geological Survey, bletcher@usgs.gov;