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SFS Annual Meeting

Tuesday, May 22, 2018
14:00 - 15:30

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14:00 - 14:15: / 310 A HYDROPEAKING DAMS FACILITATE ECOLOGICAL DOMINANCE

5/22/2018  |   14:00 - 14:15   |  310 A

HYDROPEAKING DAMS FACILITATE ECOLOGICAL DOMINANCE Humans have been damming rivers for >5,000 years, but we still lack a mechanistic understanding of how dams select for or against particular species. Our objective was to determine whether hydropeaking for power generation encourages ecological dominance (the degree to which some taxa are more numerous than others) across a gradient downstream of dams and whether traits can infer mechanisms. We collected benthic invertebrates downstream (0 to 15 river miles) of seven dams exhibiting a range of average hydropeaking intensities in the Colorado River Basin. We used species abundance distributions to quantify dominance and fourth-corner modeling to determine influential traits. Dominance shifted from a few dominant taxa near the base of dams to a higher diversity of less abundant invertebrates farther from the dam. Preliminary results also suggest traits will be useful in elucidating connections between hydropeaking intensity and dominance, since we found that an increase in average hydropeaking intensity correlated with lower mayfly, stonefly, and caddisfly (but not community) richness and abundance. Our research demonstrates that flow management for hydropower leads to simplified invertebrate assemblages dominated by a small number of taxa, but effects can dissipate with distance downstream.

Erin Abernethy (Primary Presenter/Author), Oregon State University, efabernethy@gmail.com;


Jeffrey Muehlbauer (Co-Presenter/Co-Author), USGS Grand Canyon Monitoring and Research Center, jmuehlbauer@usgs.gov;


Ted Kennedy (Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, tkennedy@usgs.gov;


Richard Van Driesche (Co-Presenter/Co-Author), Oregon State University, vandrier@science.oregonstate.edu ;


David Lytle (Co-Presenter/Co-Author), Oregon State University, lytleda@oregonstate.edu;


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14:15 - 14:30: / 310 A LONGITUDINAL DRIFT RECOVERY PATTERNS DOWNSTREAM OF LARGE DAMS

5/22/2018  |   14:15 - 14:30   |  310 A

LONGITUDINAL DRIFT RECOVERY PATTERNS DOWNSTREAM OF LARGE DAMS Large dams impose a suite of physical, chemical, and hydrological changes on river ecosystems, particularly in the tailwater reaches that exist within the first several kilometers downstream of these dams. Nonetheless, surprisingly little is known about how tailwater invertebrate communities on the large rivers downstream of such dams may vary throughout these tailwater reaches. Rivers downstream of dams are thought to behave much like headwater streams in the sense of having no source of upstream colonists, for instance, but such relationships are rarely quantified. In this presentation, we will focus on patterns of invertebrate drift within the first ~15 miles downstream of dams. Using a spatially-extensive, repeat dataset spanning eight tailwaters throughout the Colorado River Basin in the western US, we will explore longitudinal recovery patterns with respect to individual taxa and functional groups, as well as the overall invertebrate community. These results will elucidate the extent to which invertebrate communities are affected by dams, and the rate at which this influence may dissipate moving downstream.

Jeffrey Muehlbauer (Primary Presenter/Author), USGS Grand Canyon Monitoring and Research Center, jmuehlbauer@usgs.gov;


Ted Kennedy (Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, tkennedy@usgs.gov;


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14:30 - 14:45: / 310 A INVERTEBRATE AND DIATOM COMMUNITY RESPONSES TO RIVER REGULATION BY WATER SUPPLY RESERVOIRS – A LARGE-SCALE MULTI-YEAR STUDY

5/22/2018  |   14:30 - 14:45   |  310 A

INVERTEBRATE AND DIATOM COMMUNITY RESPONSES TO RIVER REGULATION BY WATER SUPPLY RESERVOIRS – A LARGE-SCALE MULTI-YEAR STUDY River regulation by dam impoundment is considered one of the most significant and extensive anthropogenic impacts on riverine ecosystems globally. There is a growing body of research centred on quantifying the effects of impoundment, with a focus on the effects of individual large dams on downstream aquatic ecosystems. This study undertakes a comparison of paired regulated and control sites associated with multiple water supply reservoirs under managed flow regimes across a range of scales using multi-year invertebrate and diatom community datasets. Taxonomic and functional community composition and a range of biomonitoring metrics were analysed in association with spatio-temporal parameters (e.g. region, year) to identify consistent downstream patterns in ecological responses to impoundment. Invertebrate and diatom communities at regulated sites differed significantly from those at control sites. The effect was most significant at a regional scale, whereas biogeographical factors appeared the primary driver of community differences at the national scale. Typically, taxonomic richness was higher at regulated sites, with a lower percentage of flow-sensitive EPT taxa present. This research provides a basis for development and future implementation of environmental flows on impounded rivers.

Mike Acreman (Co-Presenter/Co-Author), Centre for Ecology and Hydrology, Wallingford, United Kingdom, man@ceh.ac.uk;


David Hannah (Co-Presenter/Co-Author), University of Birmingham, UK, D.M.HANNAH@bham.ac.uk;


Cédric Laizé (Co-Presenter/Co-Author), Centre for Ecology and Hydrology, Wallingford, United Kingdom, clai@ceh.ac.uk;


Paul Wood (Co-Presenter/Co-Author), Loughborough University, UK, p.j.wood@lboro.ac.uk;


Henk Krajenbrink (Primary Presenter/Author), Loughborough University, UK, h.j.krajenbrink@lboro.ac.uk;


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14:45 - 15:00: / 310 A ANTHROPOGENIC PRESSURES IN A LARGE TROPICAL RIVER: THE LOWER GRIJALVA IN SOUTHERN MÉXICO

5/22/2018  |   14:45 - 15:00   |  310 A

ANTHROPOGENIC PRESSURES IN A LARGE TROPICAL RIVER: THE LOWER GRIJALVA IN SOUTHERN MÉXICO Dam building and land use change are among the major threats to river ecosystems. Temporal changes in hydrology and nutrient concentrations were studied on the Grijalva, a large tropical river in southern Mexico by analyzing long-term discharge and nutrient data. Four hydroelectric dams operate in the Grijalva and conversion from forest into agriculture, pasture, and urban areas has altered the watershed. Seasonal patterns in nutrient concentrations were also compared among tributaries in the lower Grijalva by collecting additional water samples. Seasonal and long-term patterns in discharge differed between the unregulated and regulated sites probably related to dam operation. Nitrate concentration has increased through the years, which may be attributed to the expansion of agricultural and urban areas. In contrast, total phosphorus seemed to decline at sites influenced by dam operation. Higher nitrate and total phosphorus concentrations were detected in tributaries draining intensive agricultural and urban areas. These changes in the hydrology and nutrient concentrations may negatively alter local fisheries, drinking water sources, and the integrity of coastal zones on the Gulf of Mexico

Mercedes Castillo (Primary Presenter/Author), El Colegio de la Frontera Sur, México, mmcastilloecosur@gmail.com;


Alejandra Lázaro-Vázquez (Co-Presenter/Co-Author), El Colegio de la Frontera Sur, México, ale.lazaro.91@gmail.com ;


Aarón Jarquín-Sánchez (Co-Presenter/Co-Author), El Colegio de la Frontera Sur, México, jarquinecosur@gmail.com;


Laura Carrillo (Co-Presenter/Co-Author), El Colegio de la Frontera Sur, lcarrillo@ecosur.mx;


Krista Capps (Primary Presenter/Author,Co-Presenter/Co-Author), University of Georgia, kcapps@uga.edu;


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15:00 - 15:15: / 310 A SMALL DAMS CAN HAVE LARGE THERMAL EFFECTS WITH NEGATIVE IMPLICATIONS FOR COLDWATER SPECIES

5/22/2018  |   15:00 - 15:15   |  310 A

SMALL DAMS CAN HAVE LARGE THERMAL EFFECTS WITH NEGATIVE IMPLICATIONS FOR COLDWATER SPECIES The thermal impacts of the estimated 2 million dams in the U.S. are highly variable, even within geographic regions, such as the northeast. In a study of 30 small, low-head dams in Massachusetts, we found that while some dams had minimal effects on temperature, others imparted significant warming (>5 C) on downstream reaches, such that dams caused stream temperatures to exceed thermal maxima for coldwater species. In most cases, temperatures downstream of the dams did not immediately recover to upstream temperatures, and elevated temperatures persisted for large distances (0.35-4.78 km) downstream of the dam sites. Close-proximity dams on the same stream were shown to have additive warming effects, whereby the distance to thermal recovery from a dam was increased (up to 0.85 km) by the warming effect of a downstream dam. The collective warming from the high abundance of low-head dams may have shifted coldwater habitat to warmwater habitat and aided in fragmenting and isolating coldwater species in headwater streams. These results suggest that focused, watershed-scale restoration efforts may provide greater collective water quality and biotic improvements than piecemeal dam removals across the landscape.

Peter Zaidel (Primary Presenter/Author), Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, pzaidel@umass.edu;


Allison Roy (Co-Presenter/Co-Author), U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, aroy@eco.umass.edu;


Keith Nislow (Co-Presenter/Co-Author), Northern Research Station, U.S.D.A. Forest Service, University of Massachusetts Amherst, knislow@fs.fed.us;


Ben Letcher (Co-Presenter/Co-Author), U.S. Geological Survey, bletcher@usgs.gov;


Kristopher Houle (Co-Presenter/Co-Author), Massachusetts Division of Ecological Restoration, kris.houle@state.ma.us;


Beth Lambert (Co-Presenter/Co-Author), Massachusetts Division of Ecological Restoration, beth.lambert@state.ma.us;


Christopher Smith (Co-Presenter/Co-Author), U.S. Environmental Protection Agency, Region 1, chris.r.smi@gmail.com;


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15:15 - 15:30: / 310 A RIVERS IN FLUX: HYDROPSYCHE (TRICHOPTERA: HYDROPSYCHIDAE) DISTRIBUTION ALONG A LARGE RIVER DISCONTINUUM

5/22/2018  |   15:15 - 15:30   |  310 A

RIVERS IN FLUX: HYDROPSYCHE (TRICHOPTERA: HYDROPSYCHIDAE) DISTRIBUTION ALONG A LARGE RIVER DISCONTINUUM Dams that are managed for maximizing hydroelectric yields release fluctuating downstream flows that produce freshwater “intertidal zones” along river corridors, creating unfavorable habitat for aquatic invertebrates that lay eggs along river banks. We predicted that net-spinning caddisflies (Trichoptera: Hydropsychidae: Hydropsyche) would be minimally affected by fluctuating flows because adult females have been observed to oviposit at depths of 4 m. We collaborated with citizen scientists for two years to sample for caddisflies using light traps along six large rivers in the Colorado River Basin in the southwestern United States, and identified and described the distribution of 17,266 Hydropsyche individuals across six species. We used a multi-model approach to describe the occupancy, abundance, and morphological swimming adaptations of the three dominant species relative to mean daily change in stage height and other environmental variables. Contrary to our expectations, we found no correlation between individual morphology and stage change and that Hydropsyche populations were indeed vulnerable to stage change fluctuations. Our results provide insight into the unique roles of hydrology, temperature, and life history in determining species-specific distributions on a river network scale.

Anya Metcalfe (Primary Presenter/Author), USGS/NAU, ametcalfe@usgs.gov;


Ted Kennedy (Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, tkennedy@usgs.gov;


Jeffrey Muehlbauer (Co-Presenter/Co-Author), USGS Grand Canyon Monitoring and Research Center, jmuehlbauer@usgs.gov;


Jane Marks (Co-Presenter/Co-Author), Northern Arizona University, jane.marks@nau.edu;


Kimberly Dibble (Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, kdibble@usgs.gov;


Charles Yackulic (Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, cyackulic@usgs.gov;


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