6/07/2017  |   09:00 - 09:15   |  302C

CRYPTIC, SYMPATRIC DIVERSITY UNCOVERED IN LIRCEOLUS ISOPODS AT A STYGOBIONT HOT-SPOT, EDWARDS AQUIFER, TEXAS. The Edwards Aquifer in Texas supports high stygobiont biodiversity. Extending over 400 km along the Balcones fault zone, the aquifer serves as habitat for >50 described stygobitic species. A flowing artesian well on Texas State University campus has been used to study aquifer organisms for over a century. More than 30 described species have been identified from the artesian well, and many more await formal description, illustrating the site’s importance as the most diverse stygobiont site in the Edwards Aquifer. The artesian well also represents the type locality for many Edwards Aquifer species, including the asellid isopod Lirceolus smithii. Since its description in 1902, L. smithii was presumed to be the only Lirceolus species found at the artesian well site. However, in 2016, we discovered individuals that morphologically are identified as L. pilus and L. hardeni, from both recent collections and archived specimens that were erroneously identified as Lirceolus smithii in the past. We plan to strengthen these morphology-based results through molecular methods. These results are significant as they add new records for L. pilus and L. hardeni, and reveal cryptic, sympatric diversity within the Edwards Aquifer Lirceolus species complex.

William Coleman (Primary Presenter/Author), Texas State University, willcoleman@txstate.edu;


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6/07/2017  |   09:15 - 09:30   |  302C

TESTING THE MIGHTY HEADWATER HYPOTHESIS USING UPLAND STREAM ASSEMBLAGES OF ALABAMA, USA The Mighty Headwater Hypothesis (MHH) suggests that compositional differences among stream assemblages (beta-diversity) are highest in headwater streams and decline with increasing stream-size. Thus, the MHH would imply that these unique small-stream assemblages may need higher conservation priority than they currently receive. We tested the hypothesis that there is a significant negative relationship between stream-size and beta-diversity of aquatic assemblages. We collected fish and macroinvertebrate assemblages from upland streams of varying sizes (0.14 – 290.1 km2) in the Black Warrior (n = 17, Appalachian Plateau ecoregion) and Tallapoosa River (n = 16, Piedmont ecoregion) watersheds of Alabama. We calculated dissimilarity values via 2 methods to evaluate beta-diversity; a null model derived Raup-Crick (R-C) and Sorenson’s. Sorenson’s beta-diversity for Tallapoosa River fish assemblages was negatively related to stream-size (R2 = 0.28, p = 0.02), but no other relationships with Sorenson’s or R-C indices were significant. These results show little support for the MHH and suggest that its predictions do not best describe watershed-level biodiversity patterns in upland-streams of the southeastern US, possibly due to lack of environmental heterogeneity at this scale.

Eric Bauer (Primary Presenter/Author), Auburn University, efb0005@tigermail.auburn.edu;


Brian Helms ( Co-Presenter/Co-Author), Troy University, helmsb@troy.edu;


Jack Feminella ( Co-Presenter/Co-Author), Auburn University, feminjw@auburn.edu;


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6/07/2017  |   09:30 - 09:45   |  302C

Persistence and Stability of Ozark Highland Fish Assemblages in Relation to Landscape and Local Variables Studies examining relationships between land use and fish assemblage persistence and stability are rare but necessary to understand associations at multiple temporal and spatial scales. We examined persistence and stability over 32–43 years in four streams in the Ozark Highlands by repeating previous surveys. Smaller catchments (<120 km2) exhibited the lowest and most variable persistence and stability, suggesting smaller catchments were more vulnerable across time. Within smaller catchments, persistence was significantly correlated to both forest and pasture; in contrast, persistence in larger catchments was not significantly correlated to land use. Stability was significantly correlated to pasture land use in small catchments. Seven species showed significant range expansions across all four systems, and one species, Micropterus dolomieu, exhibited a range reduction (from 20 to four sites). At sites where M. dolomieu was missing, we observed colonization of M. punctulatus and M. salmoides. An apparent downstream shift of headwaters species was detected in two systems and suggests a change in upstream hydrology. In-stream habitat reflected changes in land use and may provide proximate factors that explain the correlation between assemblage shifts and land use.

Ginny Adams (Primary Presenter/Author), University of Central Arkansas, gadams@uca.edu;


Reid Adams ( Co-Presenter/Co-Author), University of Central Arkansas, radams@uca.edu;


Heather Saco ( Co-Presenter/Co-Author), Arkansas Department of Environmental Quality, hla916@gmail.com;


Chelsey Sherwood ( Co-Presenter/Co-Author), University of Central Arkansas, csherwood1@cub.uca.edu;


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6/07/2017  |   09:45 - 10:00   |  302C

SPATIAL TURNOVER OF BENTHIC COMMUNITIES IS GREATER ACROSS A FRESHWATER TIDAL HEIGHT GRADIENT THAN BETWEEN TEMPORARY AND PERMANENT PONDS Tidal freshwater invertebrate communities experience a suite of environmental conditions atypical for a freshwater habitat: twice-daily alternating drying and fish predation. Invertebrate communities in tidal freshwaters are thought to be species depauperate, supporting fewer taxa than nearby non-tidal freshwaters, but little is known about how these communities are structured. We compared benthic communities by tidal height, and then contrasted these with nearby non-tidal freshwater wetlands that varied in hydrology (temporary and permanent ponds). Communities were more strongly differentiated along a contiguous transect of tidal height than between isolated hydrologically-variable non-tidal wetlands, likely reflecting stronger gradients of desiccation risk and fish predation. While tidal freshwater wetlands generally had lower richness and abundance per square meter than non-tidal habitats, 25% of the regional species pool was unique to tidal habitats, suggesting their importance for regional diversity. Tidal freshwaters and their wetlands have been overlooked by freshwater and marine community ecologists alike; neither discipline considers tidal freshwaters to fall under their purview. As tidal freshwaters exhibit strong environmental gradients in a condensed geographic area and are amenable to manipulation, they are ideal systems for isolating mechanistic drivers in community ecology.

Jack McLachlan (Primary Presenter/Author), University of Maine, jack.mclachlan@maine.edu;


Braden Adams ( Co-Presenter/Co-Author), University of Maine, braden.adams@maine.edu;


Erin Nolan ( Co-Presenter/Co-Author), University of Maine, erin.a.nolan@maine.edu;


Jessica Haghkerdar ( Co-Presenter/Co-Author), University of Maine, jessica.haghkerdar@maine.edu;


Hamish Greig ( Co-Presenter/Co-Author), University of Maine, hamish.greig@maine.edu;


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6/07/2017  |   10:00 - 10:15   |  302C

INFLUENCE OF SALINIZATION ON MICROBIAL AND MACROINVERTEBRATE DIVERSITY AND ORGANIC MATTER DECOMPOSITION IN APPALACHIAN HEADWATER STREAMS Salinization of freshwater ecosystems is exacerbated by climate change and large-scale landuse disturbances making it a global threat to biodiversity. In theory, reductions in biodiversity should reduce rates of important ecosystem functions such as organic matter decomposition. However, this common theory is mainly based on random species loss in experimental systems whereas biodiversity loss induced by anthropogenic stressors may occur non-randomly, leaving certain tolerant taxonomic groups unaffected. We explored relationships among salinity, biodiversity (microbial and macroinvertebrate), and rates of organic matter decomposition in a stressor-specific field study across 24 Appalachian headwater streams ranging in mining-induced salinity (mean annual conductivity: 25-1500 µS/cm). Following biodiversity-ecosystem function theory, we predicted that high levels of salinity would reduce biodiversity and thus lower rates of decomposition. We found moderate to high levels of salinity reduced macroinvertebrate diversity, especially in taxa known to be sensitive to salinity (e.g. mayflies). However, decomposition rates were unaffected by increasing salinity despite biodiversity loss, contradicting biodiversity-ecosystem function theory. Our results highlight the complex relationship between biodiversity and ecosystem functions and will help predict future responses of freshwater ecosystems to widespread salinization.

Ross Vander Vorste (Primary Presenter/Author), Rivers Study Center and Department of Biology - University of Wisconsin La Crosse , vandervorste.ross@gmail.com;


Anthony Timpano ( Co-Presenter/Co-Author), Virginia Tech, atimpano@vt.edu;


Catie Cappellin ( Co-Presenter/Co-Author), Virginia Tech, ccatie94@vt.edu;


Brian Badgley ( Co-Presenter/Co-Author), Virginia Polytechnic Institute and State University, badgley@vt.edu;


Carl Zipper ( Co-Presenter/Co-Author), Virginia Tech, czip@vt.edu;


Stephen Schoenholtz ( Co-Presenter/Co-Author), Virginia Tech, schoenhs@vt.edu;


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6/07/2017  |   10:15 - 10:30   |  302C

INFLUENCE OF FISHES ON INSECT EMERGENCE FROM PRAIRIE STREAM PERMANENT WATER REFUGIA Hydrology is a major structuring force of macroinvertebrate communities in prairie streams, with permanent reaches serving as refugia during hydrologic disturbances. Macroinvertebrate densities decrease dramatically in response to hydrologic extremes, making downstream drift from perennial reaches and adult oviposition important for recolonization. Fishes might interact with hydrologic extremes if they are concentrated in permanent reaches and influence whether insects survive to emerge as adults. We examined community structure of fishes and emerging insects from permanent waters of streams at Konza Prairie Biological Station during summer 2016. Fish communities varied across permanent water sites. Total fish biomass was not correlated with total insect emergence, but orangethroat darter (Etheostoma spectabile) biomass was negatively correlated with emerging Chironomidae biomass (r²=0.43, p=0.047) and individual body size (r²=0.61, p=0.014). Predatory fish biomass and a date interaction appeared in top linear models, indicating fish may also delay insect emergence. Few studies have investigated the effects of benthic feeding fish, such as darters, on insect emergence. Understanding how fishes in prairie streams affect ecosystem structure and function will inform conservation and management of remaining grassland streams.

Sophia Bonjour (Primary Presenter/Author), U.S. Geological Survey, Columbia Environmental Research Center, sbonjour@usgs.gov;


Matt Whiles ( Co-Presenter/Co-Author), University of Florida, mwhiles@ufl.edu;


Keith Gido ( Co-Presenter/Co-Author), Kansas State University, kgido@ksu.edu;


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