SFS Annual Meeting

5/22/2018  |   11:00 - 11:15   |  410 A

THE EFFECT OF WHOLE STREAM WARMING ON INVERTEBRATE DRIFT IN ARCTIC STREAMS To predict responses to stream water warming, we studied insect drift in a upper reach (5.8°C) and a heated up lower reach (9.1°C) of a spring-fed stream and an adjacent warm stream (19-22°C) in a the geothermal area in Hengill volcano, Iceland. Chironomidae larvae dominated the drift in the unheated and heated reaches, being 10 times higher than the second abundant group, Simulium vittatum. Radix balthica (Gastropod) dominated the drift in the warm stream. Density of drifting insects fluctuated in the unheated reach of the streams, but it was stable in the heated reach and the warm stream. Drift density was similar in both reaches, but lower in the warm stream. There was no or little association between the drift of pupae and adults and emergence. Drifting Chironomidae larvae peaked in late June, late July and late August in the cold reach, and in the warm stream in early August. No such peaks were observed in the warmed up reach. Warming up stream water by 3.3°C did not alter invertebrate drift densities. Differences could be related to cover of algae and mosses in the warm-up reach and stream stream.

Gisli Mar Gislason (Primary Presenter/Author), University of Iceland, gmg@hi.is;


Aron Dalin Jonasson (Co-Presenter/Co-Author), The National University Hospital of Iceland, arondalin@gmail.com;


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5/22/2018  |   11:15 - 11:30   |  410 A

UNDERSTANDING THE RESPONSE OF GREAT LAKES ICE COVERAGE TO CLIMATE CHANGE USING A HIERARCHICAL THRESHOLD MODEL Lakes whitefish (Coregonus clupeaformis) is an important fishery in the Great Lakes region. Overfishing and habitat alterations have led to decreased fish populations in some areas within their native range. Whitefish populations have been the focus of recent efforts, such as habitat restoration. However, an important condition for whitefish recruitment is winter ice cover in their spawning areas. The impact of climate change on lake ice cover, therefore, is becoming an increasingly important factor. As the long-term average temperature change pattern can be described by the hockey stick model, variables that respond to temperature, such as a lake’s maximum ice coverage, may also be modeled using the same model. We present a multilevel hockey stick model that is applied to Great Lakes ice coverage data to model the change in peak ice coverage over time. Using the multilevel nature of the model, we are able to quantify the year that peak ice coverage started to decline and the magnitude of decline for each lake individually and for the region as a whole -- which can assist managers in deciding the allocation resources for habitat restoration and other management.

Zachary Amidon (Co-Presenter/Co-Author), University of Toledo, Zachary.Amidon@utoledo.edu;


Song Qian (Co-Presenter/Co-Author), The University of Toledo, song.qian@utoledo.edu;
Song Qian Professor of environmental statistics Department of Environmental Sciences The University of Toledo

Stephanie Nummer (Primary Presenter/Author), University of Toledo, steph.annie.nummer@gmail.com ;


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5/22/2018  |   11:30 - 11:45   |  410 A

MODELING CLIMATE-DRIVEN SHIFTS IN ADULT EMERGENCE BY AN ARCTIC CHIRONOMID COMMUNITY: POTENTIAL IMPACTS ON TUNDRA INSECTIVORES A warming Arctic has advanced chironomid emergence in tundra ponds of northern-most Alaska by about a week, relative to the 1970s. This early-summer pulse of emerging insect biomass is a crucial food resource for tundra-nesting birds, and further climate change has potential to decouple insect/bird phenologies, threatening reproductive success of arctic-breeding insectivores. We built a simulation model predicting prey energy availability for tundra-foraging birds during the growing season at Utqiagvik (Barrow), Alaska. We based the model on allometric and kinetic assumptions inherent in metabolic activity, parameterized with data on midge community composition, species-specific emergence phenologies, and pond temperatures collected at both ends of a four-decade timespan. Our model calculates the phenological pattern and energetics of the emerging insect community by summing output for 28 chironomid taxa. A single abundant species in these ponds contributes 25% of total midge community production. By altering thaw dates and temperature regimes, we can simulate changes in the timing and magnitude of resource availability for consumers. For a shorebird species with a fixed 16-day hatch-to-fledging window, pond thaw three days earlier than average can decrease production of emerging insects available to foraging chicks by 40%.

Malcolm Butler (Primary Presenter/Author), North Dakota State University, malcolm.butler@ndus.edu;


Daniel McEwen (Co-Presenter/Co-Author), Limnopro Aquatic Science, Inc., dan@limnopro.com;


Alec Lackmann (Co-Presenter/Co-Author), North Dakota State University, alec.lackmann@ndus.edu;


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5/22/2018  |   11:45 - 12:00   |  410 A

RECONCILING THE TEMPERATURE DEPENDENCE OF MACROINVERTEBRATE PRODUCTION ACROSS A NATURAL STREAM TEMPERATURE GRADIENT Ongoing climate warming necessitates improved understanding of the role that temperature plays in regulating the biological fluxes of energy and materials that underpin ecosystem processes. These fluxes are well described at subcellular and individual levels by metabolic scaling theory (MST), which predicts that they increase with temperature based on the activation energy (AE) of subcellular reactions (~0.65 eV for heterotrophic respiration). While these patterns have been shown to scale to ecosystems, environmental and life-history factors may complicate their scaling via effects on the subcomponents of these fluxes—standing biomass and growth rate. Here, we present patterns in biomass, growth rate, and production of macroinvertebrate populations and communities in geothermally-heated streams of Iceland spanning a wide temperature gradient. Mean annual body size-corrected community biomass was less sensitive to temperature (AE ~0.43 eV) than predicted by MST, while species growth rates diverged from MST predictions and showed seasonal dependence related to light availability (AE ~0.14 eV vs 0.48eV in high vs low light). Further work will reconcile these patterns, their drivers, and implications for predicting the productivity of macroinvertebrates and the ecosystem functions they support under shifting temperature regimes.

James Junker (Primary Presenter/Author), University of North Texas, james.junker1@gmail.com;


Wyatt Cross (Co-Presenter/Co-Author), Montana State University, wyatt.cross@montana.edu ;


Jonathan P. Benstead (Co-Presenter/Co-Author), University of Alabama, jbenstead@ua.ed;


James Hood (Co-Presenter/Co-Author), The Ohio State University, hood.211@osu.edu;


Alexander D. Huryn (Co-Presenter/Co-Author), The University of Alabama, huryn@ua.edu;


Gisli Mar Gislason (Co-Presenter/Co-Author), University of Iceland, gmg@ghi.is;


Daniel Nelson (Co-Presenter/Co-Author), University of Oklahoma, dnelson12@crimson.ua.edu;


Jon S Olafsson (Co-Presenter/Co-Author), Icelandic Marine and Freshwater Research Institute, jon.s.olafsson@gmail.com;


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5/22/2018  |   12:00 - 12:15   |  410 A

THE NECESSITY OF HIGH QUALITY HABITAT WHEN YOU’RE LIVING ON THE EDGE: A CASE STUDY OF THE HUDSONIAN EMERALD Although widely distributed at higher latitudes, the Hudsonian emerald dragonfly (Somatochlora hudsonica, Hagen) is more sparsely distributed and less common in Colorado, the southernmost edge of its range. Here, S. hudsonica is a sensitive species whose local distribution and specific habitat requirements are generally poorly understood. In this study, we estimated likely habitat for S. hudsonica in Boulder County, CO using both a literature-based habitat suitability index and species distribution models trained using prior recorded occurrences. We then ground-truthed these suitability maps by surveying for S. hudsonica at ponds and lakes across a range of predicted suitabilities within the county. Our literature-based habitat suitability index proved to be significantly higher at ponds where we found S. hudsonica compared to those where we did not observe the species. Furthermore, ponds where we found S. hudsonica tended to be at higher elevation, have a higher percentage of intact forest within 500m, and have better water quality than those ponds where S. hudsonica was absent. Together, these results indicate the necessity of protecting small, snow-fed mountain ponds from anthropogenic disturbances that would prevent them from providing adequate habitat for this thermally restricted species.

Kristofor Voss (Primary Presenter/Author), Regis University, kvoss@regis.edu;


Katrina Loewy (Co-Presenter/Co-Author), Butterfly Pavilion, kloewy@butterflies.org;


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5/22/2018  |   12:15 - 12:30   |  410 A

IS A WIDESPREAD, COMMON SPECIES ALREADY LIVING NEAR ITS UPPER THERMAL TOLERANCE LIMIT IN ITS NATURAL ENVIRONMENT? Thermal stress on freshwater mussels will likely increase due to multiple factors including global warming, and drought. Assessing thermal tolerance of freshwater mussels is essential for determining the level of risk posed by these pressures. We used electron transport system (ETS) assays to examine effects of increasing temperatures on respiratory enzymes of Amblema plicata collected from populations in the lower Colorado River (Texas), the Sipsey River (Alabama), and the Little River (Oklahoma). Preliminary analysis provided no evidence for regional differences in thermal tolerance among populations. Optimal temperature for enzymes was 26.83 °C ± 2.06. Water temperatures in all three rivers frequently exceed this optima, indicating mussel populations regularly experience thermal stress. As temperatures exceed thermal optima, enzyme activity levels declined, and then plateaued – indicating the activation of chaperone molecules. This breakpoint coincided with reported lethal temperatures and occurred at 35.80 °C ± 2.84 – which is exceeded in some years. Results suggest southern populations of A. plicata are living near their thermal tolerance limit and frequently experience sublethal and lethal thermal stress. Future increases in riverine thermal regimes may threaten even common species such as A. plicata.

Austin Haney (Co-Presenter/Co-Author), Auburn University, arh0093@auburn.edu;


Carla L. Atkinson (Co-Presenter/Co-Author), The University of Alabama, carla.l.atkinson@ua.edu;


James Stoeckel (Co-Presenter/Co-Author), Auburn University, jimstoeckel@auburn.edu;


Hisham Abdelrahman (Primary Presenter/Author), School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, hisham@auburn.edu;


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