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U.S. Department of the Interior U.S. Geological Survey Dammed and Adrift: Patterns of invertebrate drift throughout Colorado River Basin tailwaters Jeff.

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Presentation on theme: "U.S. Department of the Interior U.S. Geological Survey Dammed and Adrift: Patterns of invertebrate drift throughout Colorado River Basin tailwaters Jeff."— Presentation transcript:

1 U.S. Department of the Interior U.S. Geological Survey Dammed and Adrift: Patterns of invertebrate drift throughout Colorado River Basin tailwaters Jeff Muehlbauer, Ted Kennedy Grand Canyon Monitoring and Research Center, Southwest Biological Science Center, USGS

2 What is invertebrate drift? (And why should you care?)  Entrainment of bugs in water column  Critical life stage/behavior  Food for fish Mmm, drifting bugs…

3 Key components of drift  Related to time of day  Related to discharge (floods/seasonality)  Need benthic source population

4 But that’s for small, “natural” streams What about drift in a large-river, consistently cold-temperature, fluctuating water-level, no source-population environment?  AKA, a Tailwater

5 Key components of drift  Related to time of day  Related to flow (floods/seasonality)  Need benthic source population Dam tailwaters ? ? Dam

6 Drift in tailwaters  Measureable response to dam impacts  Drift still fundamental, even in tailwaters  Does flow manipulation affect downstream recovery?  How do flows alter community dynamics?

7  Glen Canyon Dam, Grand Canyon, Arizona  0 EPT taxa. Only 2 insects  Drift related to distance downstream River mile # / m 3 Accumulation with distance from Dam 0 (Dam) 51015 0 (Dam) 51015 One “unique” ecosystem Big dam Big river Big canyon Is this normal for tailwaters? How can we tell?

8 Sampling drift  6 tailwaters in Colorado River Basin X X X X X X X Fontenelle Flaming Gorge Navajo Glen Canyon Hoover Davis Parker

9 Sampling drift  6 tailwaters in Colorado River Basin  15-mile reaches, sampled every mile

10 Sampling drift  6 tailwaters in Colorado River Basin  15-mile reaches, sampled every mile  Spring, summer, fall 2015

11 Sampling drift  6 tailwaters in Colorado River Basin  15-mile reaches, sampled every mile  Spring, summer, fall 2015  Also collected benthics -- Erin Abernethy, P119 (poster session tonight!!)

12  Are there seasonal patterns to the data? 59,378 invertebrates later… Yes! But bigger story is dam-to-dam variation

13  Is downstream recovery consistent? Dam-to-dam variation Not at all! Local factors hugely important Sediment loading Trib inflow Blackfly abatement

14 Does context matter?  Dams vary notably in several ways TailwaterLatitudeDischarge (Q)HI Fontenelle42.02460.01 Navajo36.81100.02 Flaming Gorge40.91540.13 Glen Canyon36.943600.17 Davis35.205210.36 Parker34.303340.40 Hoover36.014120.56 HI: Hydropeaking index = mean daily CV in Q (Dibble et al. 2015 EcoApps)

15 Response metric  Focusing on ratio of insects : non-insects (for now)  Insects:  Egg-laying vulnerable to hydropeaking  Kennedy et al. 2016 BioScience  Talk Wed. 13:45, S10 :

16 Latitude  Meh

17 Discharge  Well, it’s better than latitude

18 Hydropeaking Index (HI)  Darn good predictor  Matters far more than latitude or Q (classic predictors)

19 Summary  Season and context affect tailwater drift  Still searching for “unified theory of tailwaters”  Hydropeaking bad for insects  Not such a big deal for non-insects? Season Context Hydropeaking

20 Thanks to a startlingly large group of really smart, good people  USGS Flyco lab: Adam Copp, Moriah Evans, Anya Metcalfe, Tom Quigley, Eric Kortenhoeven, Ali Ingram, Dallana Garcia-Pena, David Goodenough, Megan Daubert, Dave Foster, Kim Dibble  USU Bug Lab: Scott Miller, Matt Schroer  OSU Lab: Dave Lytle, Erin Abernethy, Richard Van Driesche  …and Colden Baxter Funding from: US Bureau of Reclamation Western Area Power Administration

21 Related SFS 2016 presentations on hydropeaking in Colorado River Basin tailwaters  Scott Miller: C10, Sun, 14:00  Anya Metcalfe: S22, Mon, 14:00  Moriah Evans: S25, Poster 73  Erin Abernethy: C06, Poster 119  Jesse Fleri: C06, Poster 118  Ted Kennedy: S10, Wed, 13:45 Holy cow, you can still see these!


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