SFS Annual Meeting

5/21/2018  |   09:00 - 09:15   |  410 B

FLOW REGIMES FILTER SPECIES TRAITS OF BENTHIC DIATOM COMMUNITIES AND MODIFY THE ECOSYSTEM FUNCTIONS OF LOWLAND STREAMS – A NATIONWIDE SCALE STUDY Global changes in land use, climate and flow diversion are key drivers of flow regime change that may eventually affect freshwater biodiversity and ecosystem functions. However, our knowledge on how the functional features of stream organisms vary along the gradient of hydrological disturbance and how flow regimes mediate the ecosystem function in lowland streams is limited. Here we show that species turnover with displacement of sensitive species by tolerant species was the dominating process in benthic diatom communities during high flow disturbances. Ecosystem function was mediated mainly by high and low flow magnitude and high flow frequency. Median daily flow magnitude shows a consistent positive relationship with ecosystem functional indices indicating that larger streams are more resilient to flow perturbations. Furthermore, flow disturbances are less important and show inconsistent correlation to ecosystem function likely due to the interaction of multiple environmental stressors. Our study highlights the robustness of trait-based approaches for identifying flow regime changes in streams, and strongly suggests that biodiversity conservation and water resource management should focus on protecting natural base flow in headwater streams and generally reduce flow regulation for sustaining stream ecosystems under future global changes.

Naicheng Wu (Primary Presenter/Author), Aarhus University, naichengwu88@gmail.com;


Hans Thodsen (Co-Presenter/Co-Author), Aarhus University, hath@bios.au.dk;


Annette Baattrup-Pedersen (Co-Presenter/Co-Author), Aarhus University, Denmark, ABP@bios.au.dk;


Tenna Riis (Co-Presenter/Co-Author), Aarhus University, Denmark, Tenna.riis@bio.au.dk;


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5/21/2018  |   09:30 - 09:45   |  410 B

QUANTIFYING THE STRUCTURAL AND FUNCTIONAL RESPONSES OF MACROINVERTEBRATE COMMUNITIES TO ANTHROPOGENICALLY ALTERED FLOWS OVER A >20 YEAR PERIOD The flow regime of lotic environments is widely regarded as a primary control shaping the structure and function of river ecosystems. Hydrological alterations within such environments have been proven to degrade the health of river environments globally. However, the ecological implications of groundwater abstraction practices have been historically understudied. In this study, we utilize a regional groundwater model to examine long-term (1995-2016) macroinvertebrate community responses to antecedent observed hydrological variability and the percentage of daily flows modified by anthropogenic activities (including groundwater abstraction practices). Both the structure and function of macroinvertebrate communities responded to observed hydrological variability (including flood and drought and events) and anthropogenic flow alterations. Results from this study could be used to guide environment regulators and regional water companies on how specific hydrological events and modified flow regimes are shaping lotic ecosystems over long-term periods.

James White (Primary Presenter/Author), University of Birmingham, j.c.white.1@bham.ac.uk;


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


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


Andy House (Co-Presenter/Co-Author), Wessex Water, andy.house@wessexwater.co.uk;


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5/21/2018  |   09:45 - 10:00   |  410 B

FLOW ALTERATION AND FUNCTIONAL FLOW METRICS FOR CALIFORNIA STREAMS Managing streamflows for ecological outcomes requires understanding the natural flow regime, the current flow regime, and flows needed to achieve ecological objectives. We utilized machine learning statistical models to predict natural monthly flows for all stream reaches in California from 1950 to 2015. We compared observed flows measured at 540 stream gages across the state with modeled natural flows at the same locations, to quantify flow alteration over the past 20 years. We found that 95% of gages in California had at least one month of altered flows and 11% of all gages were altered over 66% of months. Most gages exhibited both flow inflation (flows higher than expected) and depletion (flows lower than expected). Inflation was most prevalent during summer while flow depletion occurred year-round. Depleted monthly flows averaged 20% of expected natural flows, while inflated flows averaged 10 times natural. The modeling approach will be used to predict natural functional flow metrics for every stream in California to inform environmental flow management. Prediction intervals around these metrics will be used to establish initial statewide environmental flow recommendations that can be refined according to management needs and ecological objectives.

Julie Zimmerman (Primary Presenter/Author), The Nature Conservancy, julie.zimmerman@tnc.org;


Daren Carlisle (Co-Presenter/Co-Author), U.S. Geological Survey, dcarlisle@usgs.gov;


Jeanette Howard (Co-Presenter/Co-Author), The Nature Conservancy, jeanette_howard@tnc.org;


Ted Grantham (Co-Presenter/Co-Author), University of California, Berkeley, tgrantham@berkeley.edu;


Larry Brown (Co-Presenter/Co-Author), U.S. Geological Survey, lrbrown@usgs.gov;


Jason May (Co-Presenter/Co-Author), U.S. Geological Survey, California Water Science Center, jasonmay@usgs.gov;


Kirk Klausmeyer (Co-Presenter/Co-Author), The Nature Conservancy, kirk_klausmeyer@TNC.ORG;


Eric Stein (Co-Presenter/Co-Author), Southern California Coastal Water Research Project, erics@sccwrp.org;


Sarah Yarnell (Co-Presenter/Co-Author), University of California, Davis, smyarnell@ucdavis.edu;


Sam Sandoval (Co-Presenter/Co-Author), University of California, Davis, samsandoval@ucdavis.edu;


Belize Lane (Co-Presenter/Co-Author), Utah State University, belize.lane@usu.edu;


Robert Lusardi (Co-Presenter/Co-Author), University of California, Davis, ralusardi@gmail.com;


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5/21/2018  |   10:00 - 10:15   |  410 B

EVALUATING THE ECOLOGICAL AND BIOGEOCHEMICAL CONSEQUENCES OF PREFERENTIAL FLOW PROCESSES AT SEDIMENT/WATER INTERFACES We are working to advance a combined geoelectrical and heat tracing methodology to identify and characterize preferential flow processes that are influential to stream ecosystems, especially biogeochemical cycling and benthic habitats. First, we will show how the use of bulk geoelectrical measurements that are paired with fluid sampling during conductive tracer injections can quantify solute exchange at the centimeter-scale in streambed sediments. Reactive tracers can be overlaid with these geoelectrical experiments to reveal hidden processes, such as anaerobic nitrogen cycling in bulk-oxic sediments, providing direct evidence for theorized anoxic microzones in less-mobile porosity. Second, at larger scales, we will show how infrared and fiber-optic distributed temperature sensing can locate focused discharge points that create preferential spawning sites for brook trout (Salvelinus fontinalis). We show how dozens of stable groundwater discharge points were identified over multiple years in a coastal stream, yet only a small number are used for redd development, where groundwater is oxygen-rich. Further, we are developing a watershed-scale trout habitat analysis using paired air and stream temperature signal characteristics (phase/amplitude) that can efficiently assess effective groundwater depth and its relative influence on stream temperatures.

Martin Briggs (Primary Presenter/Author), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, mbriggs@usgs.gov;


Jay Zarnetske (Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, jpz@msu.edu;


Farzaneh MP Dehkordy (Co-Presenter/Co-Author), University of Connecticut, f.mahmoodpoor@uconn.edu ;


Tyler Hampton (Co-Presenter/Co-Author), Department of Earth and Environmental Sciences, Michigan State University, USA, thampton@msu.edu;


Fred Day-Lewis (Co-Presenter/Co-Author), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, daylewis@usgs.gov;


Kamini Singha (Co-Presenter/Co-Author), Department of Geology and Geological Engineering, Colorado School of Mines, Golden, CO, USA, ksingha@mines.edu;


Zachary Johnson (Co-Presenter/Co-Author), U.S. Geological Survey, Washington Water Science Center, zach.c.johnson3@gmail.com ;


Nathaniel Hitt (Co-Presenter/Co-Author), U.S. Geological Survey, Leetown Science Center, nhitt@usgs.gov;


Craig Snyder (Co-Presenter/Co-Author), U.S. Geological Survey's (USGS) , cdsnyder02@gmail.com ;


Steve Hurley (Co-Presenter/Co-Author), MA-FWS, steve.hurley@state.ma.us ;


Jud Harvey (Co-Presenter/Co-Author), U. S. Geological Survey, National Research Program, Reston, VA, USA, jwharvey@usgs.gov;


John Lane (Co-Presenter/Co-Author), U. S. Geological Survey, Hydrogeophysics Branch, Storrs, Connecticut, USA, jwlane@usgs.gov;


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5/21/2018  |   10:15 - 10:30   |  410 B

SURFACE WATER AVAILABILITY CAN REGULATE WATER QUALITY AND NUTRIENT RETENTION IN AQUATIC AGROECOSYSTEMS Surface water quantity in agricultural landscapes is changing due to increased irrigation demands, changing precipitation patterns, and advancing water use strategies. Understanding the implications of surface water depth on aquatic ecosystem structure and function is key to maintaining biodiversity and water quality, and potentially optimizing services such as nutrient retention. Continuous water quality and hydrologic monitoring, and a series of discrete experiments occurred in three shallow lake/stream systems in heavily agricultural northwest Mississippi from 2011 to 2017. Lake and stream water depth and runoff patterns were important drivers of dissolved oxygen and nutrient dynamics in these hypereutrophic, highly turbid systems. Generally, lower water levels led to overall greater benthic primary production and lower water column nutrients, but also produced overall lower and more variable dissolved oxygen concentrations. Runoff pollutants, particularly sediment, carbon, and nitrogen, were important triggers of state changes in primary producer distribution and abundance, hypoxia, and denitrification potential within lakes. As water management strategies increasingly manipulate surface water storage and move water across watersheds, there is potential to manage surface water quantity to maximize aquatic ecosystem services, while maintaining multi-use goals in agricultural landscapes.

Justin Murdock (Primary Presenter/Author), Tennessee Technological University, jnmurdock@tntech.edu;


Martin Locke (Co-Presenter/Co-Author), USDA-ARS, martin.locke@ars.usda.gov ;


Richard Lizotte (Co-Presenter/Co-Author), USDA, Agricultural Research Service, National Sedimentation Lab , richard.lizotte@ars.usda.gov;


Jason M. Taylor (Co-Presenter/Co-Author), USDA, Agricultural Research Service, National Sedimentation Lab, jason.taylor@ars.usda.gov;


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