SFS Annual Meeting

5/22/2018  |   11:00 - 11:15   |  420 A

TRIBUTARY JUNCTION, WHAT’S YOUR FUNCTION? TESTING HYPOTHESES REGARDING THREE MECHANISTIC RESPONSES IN BENTHIC COMMUNITY STRUCTURE AT TRIBUTARY JUNCTIONS Stream network connectivity is an important watershed-scale characteristic as it can influence local habitat and resources available for stream biota. Previous studies found that tributary confluences are ecologically significant locations, causing punctuations in the longitudinal organization of benthic invertebrate communities. However, there has been little effort to test mechanisms underlying these macroinvertebrate community responses, such as modified habitat structure, inputs of novel resources, and colonization from drifting invertebrates. These mechanisms were tested using colonization baskets to manipulate substrate size, organic matter, and position relative to tributary junction. Combining these data with drift sampling, we tested the following hypotheses: (1) Coarser substrate and added leaf litter upstream will partly explain the community dissimilarity upstream and downstream. (2) Drifting invertebrates from the tributary also largely contribute to upstream-downstream contrasts. (3) The largest contrasts of drift and benthic community composition occur in mid-sized tributaries, where they are sufficiently large to provide signal, yet small enough to be ecologically distinct from the mainstem channel. The extent to which these mechanisms explain changes in observed communities can provide insight into which characteristics of tributary contributions are important for maintaining stream network benthic biodiversity.

John Richardson (Co-Presenter/Co-Author), University of British Columbia, John.Richardson@ubc.ca;


David Tavernini (Primary Presenter/Author), University of British Columbia, taverninid@gmail.com;


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5/22/2018  |   11:15 - 11:30   |  420 A

EFFECTS OF FARMING SYSTEM ON AQUATIC INSECT COMMUNITIES IN THE PADDY FIELDS OF TAIWAN Agricultural intensification is one of the major threats to global biodiversity and ecosystem services. Sustainable management of agricultural lands can reduce these impacts, but few efforts have been made for paddy fields. In this study, we examine the effects of the management on aquatic insect communities under conventional and organic farming conditions in the paddy fields of north Taiwan. Our results showed that organic farming systems did not increase taxon richness and abundance. In addition, the composition of insect communities did not have a difference between organic and conventional farming systems. In our study area, the simplified landscape with high agricultural intensification would influence the farming efficiency. When considering landscape effects, further efforts are needed to evaluate the value of non-crop habitats as sources of biotic assemblages.

Ming-Chih Chiu (Primary Presenter/Author), Ehime University, Japan, mingchih.chiu@gmail.com;


Chao-Nien Koh (Co-Presenter/Co-Author), Division of Forest Protection, Taiwan Forestry Research Institute, Taiwan, nien@tfri.gov.tw;


Yung-Jen Lu (Co-Presenter/Co-Author), Division of Forest Protection, Taiwan Forestry Research Institute, Taiwan, yungjenlu@gmail.com;


Hsing-Juh Lin (Co-Presenter/Co-Author), Department of Life Sciences, National Chung Hsing University, Taiwan ROC, hjlin@dragon.nchu.edu.tw;


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5/22/2018  |   11:30 - 11:45   |  420 A

DO FRESHWATER MUSSELS INFLUENCE THE ABUNDANCE OF MACROINVERTEBRATE FUNCTIONAL FEEDING GROUPS? Freshwater mussels are ecosystem engineers that occur as multi-species aggregations (mussel beds) that are patchily distributed in streams. Mussels alter physical habitat structure, act as nutrient capacitors, and their filter feeding can alter seston concentrations and composition in the water overlying them. We hypothesized that freshwater mussels, by altering food resource availability, would influence the abundance of different macroinvertebrate functional feeding groups. To test this hypothesis, we performed a field experiment in a small river in southeastern Oklahoma, the Kiamichi River. We used 50, 0.25m2 enclosures which were buried 20 cm deep in the sediment. Treatments were mussels (2 species combined, Actinonaias ligamentina and Amblema plicata; n=20), sham mussels (shells filled with sand; n = 20), and a sediment only control (n=10). Macroinvertebrates were collected after 12 weeks, identified, and measured. Preliminary results show decreased relative abundance of grazing mayflies (Heptageniidae) and increased abundance of predatory caddisflies (Polycentropidae Polycentropus spp.) in treatments with live mussels compared to controls, but few differences between treatments with live mussels compared to sham shells. These results indicate that the biogenic structure provided by mussels might facilitate predators.

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


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


Caryn Vaughn (Co-Presenter/Co-Author), University of Oklahoma, cvaughn@ou.edu;


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


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5/22/2018  |   11:45 - 12:00   |  420 A

FUNCTIONAL DIVERSITY OF AQUATIC MACROINVERTEBRATES ALONG A STREAM-SIZE GRADIENT IN THE COLORADO ROCKIES While the pattern of aquatic macroinvertebrate communities along a size gradient has been examined in past studies, it is usually in the context of the river continuum, moving along a stream network from the headwaters to large rivers. This is problematic because many additional aspects of streams are changing along this gradient. The pattern of how macroinvertebrate communities change along a subtle size gradient is not well known, especially in terms of functional traits like functional feeding group and habitat preference. Macroinvertebrate communities from 15 first and second order streams in the Cache la Poudre watershed in the Colorado Rockies that differed in size were sampled and analyzed to see how taxon and functional diversity differs predictably along these gradients.

M Holliday Lafferty (Primary Presenter/Author), Colorado State University , mhollylafferty@gmail.com;


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5/22/2018  |   12:00 - 12:15   |  420 A

DYNAMICS OF MACROINVERTEBRATE DRIFT IN STREAM NETWORKS While the importance of drift is well documented, it is unclear how drift behavior varies with position in a stream network and what this variation means for community assembly dynamics. Based on the results of previous theoretical and empirical work, we predicted that similarity between drift and the benthic community would be higher in headwaters than in mainstems.We also predicted that drift density, richness, and diversity would be higher in mainstems than tributaries. As a corollary, we also predicted that drift in higher order streams would be less similar to the benthos because of dispersal pressure from connecting tributaries. We collected drift samples along two sites in one river networks in Virginia at an incoming first order tributary and 20m away in the mainstem. We collected drift samples for after sunset and benthic samples after each drift sample. Preliminary results showed that drift density and richness was higher in the mainstems than tributaries, although only drift density was significant. Diversity showed an opposite pattern, with tributaries having a higher diversity than mainstems. As further analysis continues, how drift differs within a network will become more clear.

Sara Cathey (Co-Presenter/Co-Author), Virginia Tech, catheyse@vt.edu;


Bryan Brown (Co-Presenter/Co-Author), Virginia Tech, stonefly@vt.edu;


Savannah Justus (Primary Presenter/Author), Virginia Tech, sjustus1@vt.edu;


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5/22/2018  |   12:15 - 12:30   |  420 A

NEOTROPICAL CLOUD-FOREST STREAMS: MACROINVERTEBRATE REGIME SHIFTS, FOOD WEBS, AND CONSEQUENCES OF NON-NATIVE RAINBOW TROUT The structure and function of cloud-forest Neotropical streams is becoming clearer, and ongoing research is particularly relevant given their propensity for harboring unique, endemic species. However, there is much that remains unknown. For the past five years, we explored the shift in benthic macroinvertebrate communities in several headwater Neotropical cloud-forest streams in Ecuador, examined food web structure using stable-isotopes, and looked at the potential impacts from the presence of non-native rainbow trout (Oncorhynchus mykiss). Results indicated a significant yearly variation in the macroinvertebrate communities (% similarity ranged from 27-50) and significant variation in the most abundant taxa as well. Multivariate analysis indicated that there was not significant variation in physicochemical characteristics, suggesting natural variation in response to yearly differences in precipitation and/or highly dynamic communities. Analysis of functional attributes (feeding guilds) indicated a prevalence predators and low number of shredders-consistent with previous studies in the Neotropics, and stable isotope signatures suggested N-limitation and a closer overlap between scraping guilds and FPOM rather than periphyton. Finally, streams with vs. without trout farms had more pollution-tolerant macroinvertebrate taxa. Ongoing work explores the decomposition rates in rainbow trout vs. non-rainbow trout streams.

Eric Snyder (Primary Presenter/Author,Co-Presenter/Co-Author), Grand Valley State University, snydeeri@gvsu.edu;


Anna Harris (Co-Presenter/Co-Author), Canadian Organization for Tropical Education & Rainforest Conservation, a.harrianna@gmail.com;


Dana Wessels (Co-Presenter/Co-Author), Grand Valley State University, wesselsd@mail.gvsu.edu;


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