SFS Annual Meeting

5/22/2018  |   14:00 - 14:15   |  420 A

AQUATIC INVERTEBRATE COMMUNITIES VARY BETWEEN STREAMBED HABITATS WITH VARIABLE CONNECTION TO THE HYPORHEIC ZONE IN AN OZARK GRAVEL-BED STREAM The hyporheic zone provides unique habitat for aquatic invertebrates and influences diversity and productivity in streams. The Ozark Highlands ecoregion is dominated by karst topography, containing streams with bedrock-lined reaches alternating with deep, gravel-bedded reaches. Comparing benthic invertebrate communities between bedrock- and gravel-lined reaches can help address a question of hyporheic zone impact on diversity and productivity. We are sampling invertebrates in an Ozark reference stream regularly for a calendar year from three habitats: bedrock benthic, gravel-bed benthic, and hyporheic (~30-45cm below the streambed), to determine if assemblages vary in density, taxonomic richness, composition and (ultimately) secondary production. Preliminary results suggest benthic densities are similar but taxonomic richness is higher in the gravel-lined reach than in the bedrock-lined reach and community composition is different. Furthermore, we have documented taxa in the hyporheic zone not detected in any of the streambed samples. The hyporheic zone is likely important for invertebrate development and production and might provide essential refugia from drought and flood. With the hyporheic zone threatened in many streams by sediment deposition, it is essential we understand the possible impacts to invertebrate communities.

Debra Finn (Co-Presenter/Co-Author), Missouri State University, dfinn@missouristate.edu;
Associate Professor Stream Ecology

Nathan Dorff (Primary Presenter/Author), Missouri State University, natedorff@gmail.com;


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5/22/2018  |   14:15 - 14:30   |  420 A

TEMPORAL VARIATION IN SPATIAL STRUCTURING DURING MACROINVERTEBRATE COMMUNITY ASSEMBLY IN FLOODPLAIN PONDS: A FIELD EXPERIMENT It is well established that both spatial dynamics and environmental filtering can affect the structure of ecological communities, but the temporal shifts in the relative importance of these processes remain largely unexplored. However, temporal dynamics are central to the functioning of many ecosystems, for instance in highly dynamic alluvial floodplains, where habitat patches undergo frequent cycles of disturbance-recovery. In order to examine the temporal shifts between environmental filtering and spatial structuring, we excavated 24 ponds out of a gravel bar in the Maggia River floodplain (Switzerland) and monitored the assembly of the macroinvertebrate communities during the summer of 2016. At the outset of community assembly, environmental differences linked to different hydrological settings resulted in the community being structured by a combination of mass effects and species sorting. As the assembly progressed, the effect of the environment on community structure decreased and communities converged. This structural convergence was strongly affected by the distance to source habitats. Overall, spatial location with regard to source habitats exerted a strong influence on community composition and functional diversity, and this effect was strongly dependent on the level of productivity in the receiving habitat patches.

Pierre Chanut (Primary Presenter/Author), EAWAG (Swiss Federal Institute of Aquatic Science and Technology), pierre.chanut@eawag.ch;


Francis Burdon (Co-Presenter/Co-Author), Swedish University of Agricultural Sciences, Uppsala, Sweden, francis.burdon@slu.se;


Thibault Datry (Co-Presenter/Co-Author), INRAE, France, Thibault.datry@inrae.fr;


Christopher Robinson (Co-Presenter/Co-Author), Swiss Federal Institute of Aquatic Science and Technology, EAWAG ; Aquatic Ecology dpt., Christopher.robinson@eawag.ch;


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5/22/2018  |   14:30 - 14:45   |  

DO TROPHIC SUBSIDIES AND HABITAT PROVIDED BY MUSSELS INFLUENCE THE OCCURRENCE OF FISHES? Freshwater mussels occur as large multi-species aggregations that are spatially heterogeneous in streams. Mussels provide trophic subsidies via nutrient excretion and biodeposition and their shells provide biogenic habitat. These factors often result in increased primary production and macroinvertebrate abundance in areas with high mussel biomass, which might attract fishes. We performed a field experiment to test if fish occurrences were influenced by the presence of trophic subsidies associated with live mussels or biogenic habitat of shells. We used underwater video cameras to quantify fish occurrences at 50, 0.25 m2 experimental enclosures stocked with either live mussels (two species), sham mussels (shells filled with sand), or sediment only. Probability of occurrence for fish was higher in live mussel and sham treatments compared to the sediment only treatment. However, there was no difference between live mussel and sham treatments, suggesting habitat provided by mussel shells may benefit co-occurring fishes. Understanding the distribution of multiple consumer groups is important because aggregated communities may act synergistically to concentrate the ecosystem level effects of each group.

Garrett Hopper (Primary Presenter/Author), Kansas State University, ghopper@ksu.edu;


Traci DuBose (Co-Presenter/Co-Author), University of Oklahoma, tracipopejoy@ou.edu;


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


Caryn C. Vaughn (Co-Presenter/Co-Author), University of Oklahoma, carynvaughn@gmail;


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5/22/2018  |   14:45 - 15:00   |  

THE COLLECTIVE EFFECTS OF WASTEWATER EFFLUENT AND INDIVIDUAL EFFECTS OF CAFFEINE ON STREAM BIOFILMS Background/Methods: The introduction of wastewater effluent to receiving streams brings possible effects on species interactions, food webs and aquatic-terrestrial linkages. With this study, we focused on these effects on biofilm at the base of the stream food web. We also aim to tease out the effects of caffeine on stream biofilm, as it is commonly associated with effluent. We collected samples of effluent from 12 wastewater facilities in Northwest Ohio, as well as stream water upstream and downstream of each outfall location in receiving streams. These water samples were tested for the concentrations of various nutrients and of caffeine (ELISA). Biofilm was collected at these same locations and analyzed for microbial community composition (16s and 18s sequencing) and nutritional values (C:N:P). Conclusions/Results: This study resulted in significant differences in DRP, NO2NO3, and caffeine concentrations among upstream, outfall, and downstream sampling locations. There were also significant differences in biofilm eukaryotic community composition and C:P values. This study was invaluable in formulating multiple hypotheses regarding the collective effects of effluent as well as justifying a follow-up study on the effects of caffeine in the field via chemical diffusing substrata.

Melanie Marshall (Primary Presenter/Author), Bowling Green State University, melaniemarshall14@gmail.com;


Kevin McCluney (Co-Presenter/Co-Author), Bowling Green State University, kmcclun@bgsu.edu;


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5/22/2018  |   15:00 - 15:15   |  

IMPACTS OF A DAM REGULATED FLOW REGIME ON PRIMARY AND SECONDARY PRODUCTIVITY IN THE UPPER EEL RIVER, CALIFORNIA Flow alterations from dams in northern California watersheds can result in lower primary production into the summer, supporting fewer macroinvertebrates, especially mobile grazers, which make up a disproportionate portion of salmonid diets. The salmonid populations of the Eel River are impacted by the Potter Valley Project, a dam and diversion system on its upper mainstem. Yet, the effects of the dams on the aquatic ecosystem are not known. This comparative observational study examined the algal and benthic macroinvertebrate communities of the mainstem Eel River relative to an undammed river in the same watershed, the Middle Fork Eel River, during the summer of 2017. The steep recession limb in the spring and summer caused by the flow diversions of the Potter Valley Project quickly reduced the channel width relative to the more gradual decline witnessed in the Middle Fork. The Middle Fork Eel had significantly higher percent cover of Cladophora, t(79)=-2.74, p=.008, as well as on significantly higher chlorophyll-a concentrations, t(31)=4.10, p<0.001. By mid-summer, Chironominae and Hydroptilidae, key grazers in filamentous algae were found at abundances that were 12 and 3 times higher than those found in the mainstem Eel River.

Lara Jansen (Primary Presenter/Author), Humboldt State University, lsj68@humboldt.edu;


Alison O'Dowd (Co-Presenter/Co-Author), Humboldt State University, alison.odowd@humboldt.edu;


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5/22/2018  |   15:15 - 15:30   |  

THEY’RE PROBABLY FEELING INSECURE: INFERRING FOOD WEB STRUCTURE AND STABILITY USING PROBABILISTIC NETWORKS Understanding anthropogenic effects on food webs is a complex and logistically demanding task. Large sample sizes and allocations of effort are required for the accurate description of food webs, limiting their widespread use in ecological studies. However, recently developed methods offer an alternative approach to developing food webs by using proxies. Information on species body size and relative abundances, can be used with allometric scaling equations and simple food web models (such as the niche model), can be combined to infer the structure and strength of feeding interactions within size-structured food webs. We assessed the probability of species encountering one another and the probability of species being able to interact as two independent events based on relative abundance, and predator-prey body size relationships, respectively. We applied these methods to data collected on freshwater communities across a gradient of acid mine drainage (AMD) inputs. Network structure and distribution of interaction strengths were inferred, and were used to assess their robustness and stability. We found consistent, predictable changes in food web connectance and interaction strengths. This information can help inform the management and restoration of streams with a legacy of AMD inputs.

Justin Pomeranz (Primary Presenter/Author), Colorado Mesa University, jfpomeranz@gmail.com;
o Justin is an assistant professor of environmental science at Colorado Mesa University. He is a community ecologist with a special affinity for streams and benthic macroinvertebrates. Justin’s research is focused on understanding the variation in community biomass distributions from both natural and anthropogenic causes. He enjoys working with large datasets across scales and playing the banjo. Justin received a BS and MS from Colorado State University and a PhD from the University of Canterbury in New Zealand.

Helen Warburton (Co-Presenter/Co-Author), University of Canterbury, helen.warburton@canterbury.ac.nz;


Ross M. Thompson (Co-Presenter/Co-Author), Centre for Applied Water Science, University of Canberra, ross.thompson@canberra.edu.au;


Timothée Poisot (Co-Presenter/Co-Author), Université de Montréal, timothee.poisot@umontreal.ca;


Jon Harding (Co-Presenter/Co-Author), University Canterbury, jon.harding@canterbry.ac.nz;


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