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SFS Annual Meeting

Thursday, May 23, 2019
11:00 - 12:30

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11:00 - 11:15: / 250 DE LINKING ARTEMIA TO THE BENTHOS: DO MICROBIALITES SUPPORT BRINE SHRIMP PRODUCTION IN THE GREAT SALT LAKE

5/23/2019  |   11:00 - 11:15   |  250 DE

LINKING ARTEMIA TO THE BENTHOS: DO MICROBIALITES SUPPORT BRINE SHRIMP PRODUCTION IN THE GREAT SALT LAKE Benthic primary production is recognized as an important foundation of lake food webs. However, our understanding of benthic resource contributions in inland saline lakes, which contain as much water as freshwater lakes on a global scale and provide important resources for birds, is incomplete. The Great Salt Lake (GSL; Utah, USA), an important stop-over site for migratory birds, contains abundant brine shrimp (Artemia franciscana) that primarily feed on phytoplankton. By mid-summer, brine shrimp have overgrazed this primary food source, and the only alternate food source comes from benthic primary production, which in GSL occurs on microbialites, carbonate rock structures formed by bacteria and algae. This research examines the contribution of microbialite algae as a food source for brine shrimp during summer phytoplankton depletion. Preliminary carbon and nitrogen stable isotope ratios indicate that brine shrimp rely on an increasing proportion of benthic resources during summer, while pelagic resources are consumed earlier in the spring. This research complements laboratory feeding experiments that suggest brine shrimp can survive when only benthic resources are available and will be used to inform managers of the importance of benthos to brine shrimp production in the GSL.

Katherine L. Barrett (Primary Presenter/Author), University of Notre Dame, kbailey9@nd.edu;


Gary E. Belovsky (Co-Presenter/Co-Author), University of Notre Dame, gbelovsk@nd.edu;


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11:15 - 11:30: / 250 DE FISH INVADERS INVOKE TROPHIC NICHE SHIFTS IN NATIVE SPECIES

5/23/2019  |   11:15 - 11:30   |  250 DE

FISH INVADERS INVOKE TROPHIC NICHE SHIFTS IN NATIVE SPECIES Past and ongoing species introductions to freshwater ecosystems have made novel assemblages increasingly common. In these assemblages, an ongoing challenge is identifying and predicting non-native species food-web impacts to address the management of vulnerable species. Using a gradient of invasion from unimpacted native-only assemblages to assemblages completely replaced by non-native species, our objective was to determine how trophic niche and resource use of native and non-native fishes respond in each other’s presence. We then tested for recovery in the patterns of trophic niche shifts before and after non-native species removal managed by the local state agency. We used natural abundance Carbon and Nitrogen stable isotope data to evaluate species niches in the Bill Williams watershed, Arizona, USA. Circular statistics and Bayesian Standard Ellipse Areas helped us examine shifts in trophic resource use and overlap. In the presence of non-native species, native species had significant shifts in directionality toward lower trophic level and different basal resources, but non-native species showed variable and non-significant responses to the presence of native species. Native species with the highest overlap with non-native species niches had the highest potential for recovery after non-native species removal.

Jane Rogosch (Primary Presenter/Author), University of Washington, jfencl@uw.edu;


Julian Olden (Co-Presenter/Co-Author), University of Washington, olden@uw.edu;


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11:30 - 11:45: / 250 DE DIETARY COMPARISONS OF FISHES IN THE U.S AND MONGOLIAN MOUNTAIN STEPPE

5/23/2019  |   11:30 - 11:45   |  250 DE

DIETARY COMPARISONS OF FISHES IN THE U.S AND MONGOLIAN MOUNTAIN STEPPE Compared to the United States, rivers in Mongolia are minimally impacted by human development. As part of a larger macrosystems project we focused on the diets of fishes located in both the U.S. and Mongolian Mountain Steppe ecoregions. We analyzed gut contents from fishes collected across multiple sites on each continent to compare diets among species and functional groups. The results of this will be used in conjunction with future sampling efforts that will complete in the summer of 2019 in the Mongolian Grassland.

Mark Pyron (Co-Presenter/Co-Author), Ball State University, mpyron@bsu.edu;


Emily Arsenault (Co-Presenter/Co-Author), University of Kansas, erarsenault@ku.edu;


Caleb Artz (Co-Presenter/Co-Author), Ball State University, ccartz@bsu.edu;


Robert Shields (Co-Presenter/Co-Author), Ball State University, rcshields@bsu.edu;


Gregory Mathews (Co-Presenter/Co-Author), University of Kansas, gsmathews@ku.edu;


Mario Minder (Primary Presenter/Author), Ball State University, mmminder@bsu.edu;


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11:45 - 12:00: / 250 DE STAGE-STRUCTURED PREDATION BY FISH IN LINKED AQUATIC-TERRESTRIAL FOOD WEBS: A MESOCOSM EXPERIMENT

5/23/2019  |   11:45 - 12:00   |  250 DE

STAGE-STRUCTURED PREDATION BY FISH IN LINKED AQUATIC-TERRESTRIAL FOOD WEBS: A MESOCOSM EXPERIMENT Stage-structured feeding within food web models can alter predictions about predator-prey interactions because 1) susceptibility to predation varies across life-stages and 2) trophic ecology varies across life-stages. The life-cycles of prey species can influence their availability to predators, altering nutrient flow in a system. In this study, we used mesocosms to determine the effects of stage structuring within the diets of Common Carp (Cyprinus carpio, a benthic feeder) and Spotfin Shiner (Cyprinella spiloptera, a water column feeder). We show that stage-structured feeding was present within this system (spotfin at a higher proportion of pupal prey than carp) and that the difference in stage-structured feeding was greatest during peak insect emergence events. This study demonstrates the presence of stage-structuring in the diets of Missouri River fishes and leads to different predictions of how these fishes impact insects in their larval stages (strong, direct effects of carp but not spotfin) versus emerging adult stages (strong effects of both fishes).

Jeff Wesner (Co-Presenter/Co-Author), University of South Dakota, Jeff.Wesner@usd.edu;


Abraham Kanz (Primary Presenter/Author), University of South Dakota, Abrahamkanz@gmail.com;


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12:00 - 12:15: / 250 DE IMPACTS OF RIVER MODIFICATIONS ON FOOD WEBS – LESSONS FROM COLLECTIONS IN AUSTRALIA AND THE AMERICAN SOUTHWEST

5/23/2019  |   12:00 - 12:15   |  250 DE

IMPACTS OF RIVER MODIFICATIONS ON FOOD WEBS – LESSONS FROM COLLECTIONS IN AUSTRALIA AND THE AMERICAN SOUTHWEST River flow homogenization caused by dam and weir construction has been correlated with reduction of community niche breadth, as predicted by food web theory. Stable isotope analysis of natural history collections has been invaluable in gaining these insights. Pre-alteration conditions can be established with sufficient collections, allowing for post-alteration comparisons. However, some portion of food web shifts that have been correlated with dam/weir construction may be confounded by other anthropogenic disturbances, particularly effluent from agriculture and human settlements. Advances in stable isotope techniques may make it possible for ecologists to trace baseline shifts in primary production values that would express itself throughout the food web. Here, using collections, we examine food webs from two analog aridland river systems which were heavily modified in the 20th century: the Murray-Darling (Southeast Australia) and the Rio Grande (Southwest U.S.).

Gregor Hamilton (Primary Presenter/Author), University of New Mexico, ghamilton@unm.edu;


Thomas Turner (Co-Presenter/Co-Author), University of New Mexico, turnert@unm.edu;


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12:15 - 12:30: / 250 DE URBAN STREAM GEOMORPHIC CHARACTERISTICS STRONGLY INFLUENCE AQUATIC-TO-TERRESTRIAL SUBSIDIES AND FOOD-WEB STRUCTURE

5/23/2019  |   12:15 - 12:30   |  250 DE

URBAN STREAM GEOMORPHIC CHARACTERISTICS STRONGLY INFLUENCE AQUATIC-TO-TERRESTRIAL SUBSIDIES AND FOOD-WEB STRUCTURE Aquatic-to-terrestrial fluxes of emergent aquatic insects provide quantitatively important nutritional subsidies to a suite of riparian terrestrial consumers. However, understanding of the mechanisms and controls underlying variability in these subsidies in altered ecosystems remains in the early stages. We investigated the effects of physical habitat (i.e., hydrogeomorphic) alteration on aquatic-terrestrial subsidies in 22 urban streams in the Columbus Metropolitan Area, Ohio, USA. We found that multiple stream hydromorphic features were associated with both fluxes of emergent insects and trophic dynamics of orb-weaving riparian spiders of the family Tetragnathidae. For example, diversity (H’) of emergent insects increased in higher gradient, higher power streams, presumably owing to the more heterogeneous habitat maintained by diverse flow regimes. Tetragnathid spiders were less reliant on aquatically-derived energy (i.e., energetic pathways derived from benthic algae) in incised streams, where stream channels were physically disconnected from their adjacent riparian zones. Further, spiders occupied lower trophic positions in larger streams with finer substrate. These results contribute to the growing body of literature linking stream geomorphic and ecological processes, and to a better understanding of mechanisms underlying aquatic-terrestrial food-webs in urban watersheds.

Leslie O. Rieck (Primary Presenter/Author), The Ohio State University, rieck.6@osu.edu;


S. Mažeika P. Sullivan (Co-Presenter/Co-Author), The Ohio State University, sullivan.191@osu.edu;


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