Monday, May 21, 2018
14:00 - 15:30
5/21/2018 |
14:00 - 14:15
| 410 B
BUY ONE, GET ONE FREE: INTEGRATING ECOLOGY AND HYDROGEOLOGY TO CONSERVE ALABAMA'S BURROWING CRAYFISH POPULATIONS AND GROUNDWATER RESOURCES
Combine the desire to establish conservation opportunities for a diverse and understudied group of aquatic species with the need to learn more about Alabama’s groundwater resources, and the result is a research direction that uses borrowing crayfish habitat preferences to bridge the gap between ecology and hydrogeology. Because burrowing crayfish spend most of their lives in subterranean burrows far from surface water, they rely heavily on access to shallow groundwater, a resource that may be more limiting during periods of drought or subject to periodic withdrawals to satisfy human demands. In order to better understand the dynamics of shallow groundwater movement and its relationship to the habitat needs of burrowing crayfish, I am measuring groundwater flow, groundwater quality, soil characteristics, and the floodplain inundation potential of a 10 km reach of Bogue Chitto Creek in the Blackbelt Prairie region of Alabama. The results of this research will provide information needed to address potential habitat threats through a watershed management plan focused on burrowing crayfish conservation and supply groundwater flow data useful in the development of a statewide groundwater monitoring program.
Rebecca Bearden (Primary Presenter/Author), University of Alabama, rabearden@crimson.ua.edu;
Alexander D. Huryn (Co-Presenter/Co-Author), The University of Alabama, huryn@ua.edu;
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14:15 - 14:30: / 410 B NONSTATIONARITY IN LOW FLOWS AT SOUTHEAST U.S. STREAMFLOW GAGES
5/21/2018 |
14:15 - 14:30
| 410 B
NONSTATIONARITY IN LOW FLOWS AT SOUTHEAST U.S. STREAMFLOW GAGES
The southeast U.S. is widely perceived as a water rich region, yet recent droughts, highly variable streamflows, and rapidly growing demands for water have revealed vulnerabilities and the potential for widespread water scarcity. Recent studies have shown decreasing trends in low flows at many stream gages across the region, but have failed to identify the causal mechanisms underlying these trends. We describe low flow trend analyses of regional stream gage records in the southeast U.S. to assess water availability for multiple uses including agriculture, municipal, industrial, thermoelectric power production, and environmental flows. Statistical analyses, including the Mann-Kendall, Pettitt, and Ljung-Box tests are used to assess monotonic trends, the presence of abrupt shifts in data, and
autocorrelation, respectively. We compare our results with other studies assessing trends in low flows and perform type II error analysis to quantify the likelihood of erroneously declaring stationarity in low flows. Further, we present an investigation into potential drivers of trends in low flows across varying spatial and temporal scales and implications for future water availability in the region. Trends in streamflow reflect interactions among climatic and land use cycles, flow regulation, and groundwater withdrawals.
Brian Bledsoe (Primary Presenter/Author), University of Georgia, bbledsoe@uga.edu;
Timothy Stephens (Co-Presenter/Co-Author), University of Georgia, tas48127@uga.edu;
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5/21/2018 |
14:30 - 14:45
| 410 B
THE PAST AS A PREDICTOR: IMPORTANCE OF ANTECEDENT FLOW FOR EXPLAINING ECOLOGICAL TRENDS IN AN URBAN RIVERSCAPE
Urban streams can have highly altered flow regimes which can influence both biotic and abiotic components of riverscapes. We use data collected at 10 streamflow gaged sites from 2003-2016 to analyze how antecedent flow, habitat, and water quality are related to trends in biological assemblages of an urban stream in the transition zone from the Rocky Mountains to the Great Plains. These data include annual samples of aquatic invertebrates, fish communities, water quality, and habitat from the Fountain Creek basin, CO. We examined trends in biological communities and explored relationships between these trends and abiotic variables (antecedent streamflow, physical habitat, and water quality) using a combination of trend tests, correlation analyses, and linear regressions. Our analysis shows that the majority of significant trends decreased over this period. Overall, fish metric trends were decreasing on average by 40 percent, invertebrate metrics decreased by 9.5 percent, and antecedent streamflow was the most common explanatory variable of these trends. We also found that antecedent measures of peakflow events identified a potential threshold that limits age-0 survival for Flathead Chub (Platygobio gracilis), a species of conservation concern.
James J. Roberts (Primary Presenter/Author), U.S. Geological Survey, Ann Arbor, MI 48105, jroberts@usgs.gov;
Robert Zuellig (Co-Presenter/Co-Author), U.S. Geological Survey, rzuellig@usgs.gov ;
James Bruce (Co-Presenter/Co-Author), U.S. Geological Survey, jbruce@usgs.gov;
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5/21/2018 |
14:45 - 15:00
| 410 B
WHAT WE CAN AND CAN NOT LEARN FROM THE GEOPHYSICAL IMAGING OF THE HYPORHEIC ZONE
Researchers have long been trying to describe the size and dynamics of the hyporheic zone (HZ) and its effect on the stream’s ability to transform nutrients. Unfortunately, most of our knowledge of the HZ comes from flume experiments, which are too idealized to apply to the real world, and solute transport models, which are oversimplified and overfit, therefore muddying the link between the HZ and uptake. We used 3D geophysical imaging, electrical resistivity tomography (ERT), to measure the transfer of a conservative tracer (chloride) between surface waters and the HZ during and after a constant rate addition at 5 headwater streams. From the ERT data, we generated 3D representations of tracer abundance in the HZ through time. We also performed instantaneous additions of nitrate over the same 5 reaches to estimate uptake via TASCC. We analyzed the tracer breakthrough curves using a first-order mass transfer model in ReacTran, giving estimates of the rate of exchange and the size of the storage zone, and therefore HZ. From our experiments, we show how 3D ERT can better our understanding of how HZ size and dynamics influence nutrient transformation.
Brady Kohler (Primary Presenter/Author), University of Wyoming, kohlerbrady@gmail.com;
Kevin Befus (Co-Presenter/Co-Author), University of Wyoming, kbefus@uwyo.edu;
Brad Carr (Co-Presenter/Co-Author), University of Wyoming, bcarr1@uwyo.edu;
Robert O. Hall (Co-Presenter/Co-Author), Flathead Lake Biological Station, University of Montana, bob.hall@flbs.umt.edu;
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5/21/2018 |
15:00 - 15:15
| 410 B
EXPLORING THE SPATIAL AND TEMPORAL DRIVERS OF MACROINVERTEBRATE ASSEMBLAGES IN THE PEACE-ATHABASCA DELTA, ALBERTA, CANADA
High-throughput DNA sequencing extracted from bulk environmental samples offer an information-rich opportunity to refine metrics linked to assessment and monitoring of ecosystems threatened by anthropogenic stressors. Here we quantify the importance of spatial and temporal drivers of benthic macroinvertebrate assemblages sampled as part of a large-scale biomonitoring program over a five-year period from eight core wetland sites in the Peace-Athabasca Delta, Alberta, Canada. Structural (e.g. taxa richness) and functional-based (e.g. trait modalities) data were linked to quantified measures of ecohydrological variability (e.g. connectivity with the main channel and water level variation). The results demonstrate the importance of incorporating both structural and functional components in monitoring highly dynamic wetland systems.
Daniel Peters (Co-Presenter/Co-Author), Environment and Climate Change Canada, daniel.peters@canada.ca;
Teresita Porter (Co-Presenter/Co-Author), Natural Resources Canada, teresita.porter@canada.ca;
Mehrdad Hajibabaei (Co-Presenter/Co-Author), Centre for Biodiversity Genomics & Department of Integrative Biology, University of Guelph, ON, Canada, mhajibab@uoguelph.ca;
Donald Baird (Co-Presenter/Co-Author), Environment and Climate Change Canada @ Canadian Rivers Institute, Department of Biology, University of New Brunswick, Fredericton, NB, Canada, djbaird@unb.ca;
Wendy Monk (Primary Presenter/Author), Environment and Climate Change Canada @ Canadian Rivers Institute, Faculty of Forestry and Environmental Management, University of New Brunswick, Fredericton, NB, Canada, wmonk@unb.ca;
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15:15 - 15:30: / 410 B ALTERATION OF STREAMFLOW REGIMES IN THE UNITED STATES
5/21/2018 |
15:15 - 15:30
| 410 B
ALTERATION OF STREAMFLOW REGIMES IN THE UNITED STATES
A multitude of studies have documented how changes in stream hydrology caused by land conversion, water infrastructure, and other human activities result in fish population declines, ecosystem degradation and loss of freshwater biodiversity. Yet the nature, severity, and extent of flow alteration at regional and national scales remain unquantified despite the existence of a large, long-term gauge network in the US. A major obstacle in quantifying flow alteration is the limited availability of information on hydrologic conditions in the absence of human influence.
Here, we assessed the patterns and degree of flow alteration in streams across the conterminous US, focusing on flow regime components of known or hypothesized relevance to aquatic ecosystem health. We used statistical models to predict expected natural values of metrics of the flow regime at more than three thousand gauged sites. Predictions were then compared with observed conditions to assess deviation from natural conditions, while accounting for model prediction error.
In general, substantial reductions in variations of high- and low-flow events were associated with all human activities across the US. Different regional patterns in flow alterations were associated for each type of human activity.
Ken Eng (Primary Presenter/Author), U.S. Geological Survey, keng@usgs.gov;
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