SFS Annual Meeting

5/20/2019  |   14:00 - 14:15   |  251 DE

TAXONOMIC AND FUNCTIONAL TRAIT STRUCTURE WITHIN THE SIZE SPECTRUM: COMMON BUILDING BLOCKS OR IDIOSYNCRASY? Size-structure within aquatic communities can often be characterized by a simple scaling relationship between average body mass and abundance within log-2 size classes. This ‘size spectrum’ has been documented in a variety of ecosystems and as the empirical database grows, critical comparisons are being used to characterize central tendencies and anomalies in model parameters (regression model slopes and intercepts). The present study takes an additional step by examining taxonomic and functional trait structure within the discrete size classes that are used in traditional size spectra models. Basic model parameters will first be compared among size spectra from an array of eastern and western U.S. streams. Total biomass within each size class will then be partitioned into taxonomic and functional feeding group components (e.g. summed biomass of mayflies or predators within each size class). By comparing size-specific taxonomic and functional feeding group components among streams, I will test the hypothesis that the size spectrum is an emergent construct of common taxonomic and/or functional building blocks in temperate forested streams.

Daniel McGarvey (Primary Presenter/Author), Center for Environmental Studies, Virginia Commonwealth University, djmcgarvey@vcu.edu;


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5/20/2019  |   14:15 - 14:30   |  251 DE

AN ANALYSIS OF FUNCTIONAL DIVERSITY IN RIVERINE FISHES FROM THE GRASSLANDS TO THE GREAT BASIN Functional diversity (FD) has been utilized to gauge the health and stability of fish communities in many different environments, but has not yet been formally applied to fishes within terminal basin rivers. To accomplish this goal, we sampled fish in the Carson, Bear, and Humboldt rivers and investigated how FD changed between and within each system. As part of a larger project, we also sampled grassland and mountain steppe sites to allow FD comparisons between ecoregions. We used fish traits associated with each species’ reproduction and feeding habits to gauge community functionality. As expected, FD was found to strongly correlate with species diversity. In most comparisons the more speciose lowlands in particular provided greater FD. However, a community containing redundant species that offer no novel traits to the community can cause exceptions to this rule. This project should serve as a foundation for future large-scale FD studies in each of these ecoregions, and the terminal basin especially.

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


James H. Thorp (Co-Presenter/Co-Author), University of Kansas/Kansas Biological Survey, thorp@ku.edu;


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5/20/2019  |   14:30 - 14:45   |  251 DE

NICHE DIMENSIONALITY AND HERBIVORY CONTROL STREAM ALGAL BIOMASS VIA SHIFTS IN GUILD COMPOSITION, RICHNESS, AND EVENNESS We developed a framework for the hierarchical pathways of bottom-up (niche dimensionality) and top-down control (herbivory) on biomass of stream algae via changes in guild composition (relative abundance of low profile, high profile, and motile guilds), species richness, and evenness. Implementing a combination of field and lab experiments that manipulated for the first time in benthic algae herbivory and/or niche dimensionality, i.e. the number of added nutrients (Nnutrients), including nitrogen, phosphorus, iron, and manganese, we made the following discoveries. First, guild composition was primarily determined by herbivory; richness, by guild composition and/or Nnutrients; evenness, by guild composition and herbivory; and biomass, by guild composition and Nnutrients. Second, species richness increased with Nnutrients—a pattern inconsistent with resource competition theory. Third, supplementation with manganese and/or iron increased richness, indicating that micronutrients, which have generally been overlooked in stream ecology, added dimensions to the algal niche. Fourth, the richness-evenness relationship depended on herbivory and the size of the species pool. Finally, the greater dependence of biomass production on guild composition and Nnutrients than on richness and evenness suggests that more comprehensive, trait-based approaches are necessary for the study of the biodiversity-ecosystem function paradigm.

Sophia Passy (Primary Presenter/Author), University of Texas - Arlington, sophia.passy@uta.edu;


Chad Larson (Co-Presenter/Co-Author), Washington State Department of Ecology, clar461@ecy.wa.gov;


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5/20/2019  |   14:45 - 15:00   |  251 DE

RESILIENCE ISN’T ALWAYS HEALTHY: DISTURBING DEGRADED COMMUNITIES TO REVERSE THE EFFECTS OF ENVIRONMENTAL FILTERING To investigate how environmental filtering shapes communities, we conducted a meta-analysis of New Zealand streams across different stressor gradients. This identified distinct community types characterised by species trait composition, from low-diversity degraded systems dominated by taxa with protective structures (e.g. snails) to biodiverse springs home to mobile invertebrates (e.g. mayflies). Community resistance and resilience are characteristics usually associated with high biodiversity and good ecological health, and often underpin restoration goals. However, degraded ecosystems can also be resistant and resilient to disturbance making them highly stable and thus difficult to restore. We propose these communities must first be destabilised to facilitate recovery, requiring an understanding of how different communities respond to additional disturbance. We tested this in stream mesocosms, where impacts of contrasting stressors (flooding, sedimentation, and nutrients) on community types sourced from flood-prone rivers, stable springs and agriculturally impacted streams were assessed. A significant three-way interaction between community type, stress type and drift over time indicated that disturbance history and corresponding community type influence community stress response, with patterns often driven by particular taxa and traits. As such, stressors could be used to trigger positive community change in restoration.

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


Catherine Febria (Co-Presenter/Co-Author), University of Windsor, Catherine.Febria@uwindsor.ca;


Kristy Hogsden (Co-Presenter/Co-Author), NIWA, kristy.hogsden@niwa .co.nz;


Elizabeth Graham (Co-Presenter/Co-Author), NIWA, Elizabeth.Graham@niwa.co.nz;


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


Angus McIntosh (Co-Presenter/Co-Author), University of Canterbury, angus.mcintosh@canterbury.ac.nz;


Isabelle Barrett (Primary Presenter/Author), University of Canterbury, issie.barrett@canterbury.ac.nz;


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5/20/2019  |   15:00 - 15:15   |  251 DE

BASELINE ANALYSIS OF FRESHWATER LOTIC COMMUNITIES SURROUNDING A DECOMMISSIONED LOW HEAD DAM PRIOR TO REMOVAL Low head dams can create a variety of problems for many freshwater lotic communities. We chose to study the Allentown Dam, in Lima, Ohio, which is commissioned for removal in summer of 2019. We designated two study sites, one above the dam and one below, as well as two reference sites, for comparison. Within each site, we sampled for macroinvertebrates, periphyton, and fish. We tested for community differences with ANOVAs, looking at abundance, taxa richness, diversity, density, and other factors. We also sampled for physicochemical data at each site, and compared the data at each specific site using a CCA (Canonical Correspondence Analysis). We observed that the two Allentown Dam sites are not different from each other in both their physicochemical properties and their community compositions. However, the two reference sites were significantly different from each other and the two study sites. Our results point to the idea that the low head dam is not having any localized impact on the loti benthic community, but is likely a barrier to fish movement upstream.

Robert Verb (Primary Presenter/Author), Ohio Northern University, r-verb@onu.edu;


Everett Meredith (Co-Presenter/Co-Author), Ohio Northern University, e-meredith@onu.edu;


Zachary Bragg (Co-Presenter/Co-Author), Ohio Northern University, z-bragg@onu.edu;


Garrett Duktig (Co-Presenter/Co-Author), Ohio Northern University, g-duktig@onu.edu;


Tyler Tanto (Co-Presenter/Co-Author), Ohio Northern University, t-tanto@onu.edu;


Leslie Riley (Co-Presenter/Co-Author), Ohio Northern University, l-riley.1@onu.edu;


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5/20/2019  |   15:15 - 15:30   |  251 DE

RELATIVE IMPORTANCE OF ENVIRONMENTAL FACTORS AND COMMUNITY ECOLOGY IN RANAVIRUS TRANSMISSION The dilution effect hypothesis suggests that more diverse communities constrain pathogen spread through several mechanisms and recent meta-analyses suggest that the dilution effect is common. However, few studies of diversity-disease relationships have addressed the role of physiochemical properties that can influence community assembly and affect host and pathogen physiology. We used a system characterized by a multi-host pathogen of freshwater vertebrates, ranavirus, and assemblages of amphibians in ephemeral wetlands to quantify the relative contributions of biotic and abiotic factors on infection risk. We characterized the amphibian communities for 20 ephemeral wetlands and investigated the relationship between amphibian communities and ranavirus prevalence. We captured over 30,000 individual amphibians representing 23 species and quantified presence of ranavirus in a subset. Overall, we see an epidemic of ranavirus in spring months that, based on boosted regression tree analyses, is driven by a combination of environmental variables and specific aspects of the amphibian community. Canopy cover and water and air temperature are the most important environmental factors driving ranavirus occurrence. While species richness has no influence on ranavirus prevalence, there is a relationship between the epidemic and increased abundance of highly competent hosts.

Stacey Lance (Primary Presenter/Author), Savannah River Ecology Lab/University of Georgia, lance@srel.uga.edu;


Andrew Park (Co-Presenter/Co-Author), University of Georgia, awpark@uga.edu;


Krista Capps (Co-Presenter/Co-Author), University of Georgia, kcapps@uga.edu;
Research in Krista Capps's lab is dedicated to understanding how anthropogenic activities alter community structure and ecosystem processes (e.g., productivity, decomposition, and biogeochemical cycling) in freshwater ecosystems. Much of her research has focused on the impacts of consumers on basal food resources, community structure, and nutrient dynamics in streams and wetlands. To translate scientific knowledge to actionable outcomes, she actively works with community groups and local, state, and federal employees to develop programs that integrate stakeholder concerns into research planning.

Austin Coleman (Co-Presenter/Co-Author), University of Georgia, acolem12@uga.edu;


David Scott (Co-Presenter/Co-Author), Savannah River Ecology Laboratory, University of Georgia, scott@srel.uga.edu;


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