SFS Annual Meeting

Maria Isabel Castro-Rebolledo (Primary Presenter/Author)
Universidad de La Salle, micastro@unisalle.edu.co;

Lucía C. Lozano (Co-Presenter/Co-Author)
Universidad de La Salle , lclozano@unisalle.edu.co;

Luisa Fernanda Rojas (Co-Presenter/Co-Author)
Universidad de La Salle , rluisa17@unisalle.edu.co;

Abstract: Macroinvertebrates are important in autochthonous litter decomposition in aquatic ecosystems. In this study, aquatic macroinvertebrates colonization in a litter decomposition process of three Arecaceae family species was evaluated. Litter packet methodology was used, macroinvertebrate assembly, litter decomposition rates, and chemical characteristics of each plant species was evaluated. The greatest loss of plant biomass was recorded in Elaeis guineensis, followed by Mauritia flexuosa and Attalea butyracea litter. Reduced presence of associated macroinvertebrates in the three palm species was observed. Scrapers and collector-gatherers were the dominant functional food groups. Our results show the importance of litter chemical characteristic in detritivores activity, suggest its relevance in the organization that macroinvertebrates found in spatial and temporal scales.

H. Arthur Woods (Co-Presenter/Co-Author)
University of Montana, art.woods@mso.umt.edu;

Brian Hand (Co-Presenter/Co-Author)
Flathead Lake Biological Station, The University of Montana, brian.hand@umontana.edu;

Gordon Luikart (Co-Presenter/Co-Author)
Flathead Lake Biological Station, The University of Montana, gordon.luikart@umontana.edu;

Jack Stanford (Co-Presenter/Co-Author)
Flathead Lake Biological Station-University of Montana, jack.stanford@umontana.edu;

Rachel Malison (Primary Presenter/Author)
Flathead Lake Biological Station, The University of Montana, rachel.malison@umontana.edu;

Abstract: The sensitivity and thermal tolerance of different species to warming temperatures in part determines habitat suitability and responses to climate change. Alluvial river floodplains are home to aquifer and benthic stoneflies that inhabit environments with different temperature regimes. We predicted that aquifer stoneflies would be more sensitive to warming temperatures because they experience constantly cold temperatures, whereas benthic species experience more diurnal and seasonal temperature variability. To test this prediction, we conducted intermittent respirometry experiments on nymphs of three aquifer and five benthic species across three floodplains in western Montana. We measured movement patterns, survival, and mass-specific metabolic rates (MSMRs) on 256 individual nymphs at 3-degree increments from 6-30 ºC. Aquifer and benthic taxa showed no difference in the highest temperature at which movement occurred (28 ºC), and they survived equally well. However, the benthic species C. sabulosa did have lower survival compared to other taxa. Mean MSMRs peaked at slightly higher temperatures for aquifer vs. benthic taxa (22.4 vs 21.2 ºC), but differences were not significant. Aquifer taxa may be less vulnerable to warming temperatures given their tolerance and location within buffered aquifers.

Emily Nisch Terrell (Primary Presenter/Author)
North Carolina State University , emilyaterrell@gmail.com;

Abstract: Archaeomalacology is an untapped resource in freshwater mussel restoration, and malacology often remains a mystery to archaeologists who find mussel shells during an excavation. While researching shell tools from a Late Woodland Indigenous site in North Carolina and learning about the needs of living mussels, I started to wonder: can studying freshwater mussels in archaeological contexts help us save and protect mussels for the future? Mussels in archaeological contexts gives us a snapshot into how mussels looked, lived, and were managed in the past. We can also study how past humans interacted with mussels. For example, prehistoric fish weirs still stand in many North Carolina rivers, providing the same stable benthic environment that they have for hundreds of years. These weirs also create a semi-permeable barrier for fish, potentially resulting in a higher rate of juvenile mussel deposition. More juvenile mussels plus a propitious benthic environment may have created thriving communities of mussels. For the same reasons, these fish weirs may also host higher numbers of mussels than elsewhere in the same river and provide ideal conditions for mussel reintroduction.

Amaryllis Adey (Primary Presenter/Author)
The University of Notre Dame, aadey@nd.edu;

Abstract: As global climate is changing, multiple factors are contributing to changes in primary production. Theory suggests that dissolved organic carbon (DOC) concentrations have a hump-shaped relationship with primary productivity driven by associated increases in nutrient supply and decreases in light availability. These impacts on primary productivity have been shown to be mostly driven by decreases in benthic primary production. This decrease in benthic primary production is likely to impact benthic invertebrate communities through bottom-up effects. Here, we test how increasing DOC concentrations impact benthic invertebrate communities in a whole lake manipulation. In 2011, we began to experimentally increase the DOC concentration in half of Long Lake from 6 to 11 mg C L-1. Throughout this period, we monitored carbon, phosphorus, and nitrogen loads and pelagic food web productivity. Here we explore how the benthic invertebrate community responded to this whole-lake manipulation through assessment of community composition and biomass production. These results will provide expectations for how aquatic ecosystems will respond to an ongoing, continental-scale environmental change, by significantly increasing understanding about the implications of increased carbon loads on benthic invertebrate communities.

Zachary Mitchell (Primary Presenter/Author)
Texas State University, zmitchell9186@gmail.com;

Joshua Robledo (Co-Presenter/Co-Author)
Texas State University, j_r728@txstate.edu;

Karl Cottenie (Co-Presenter/Co-Author)
University of Guelph, cottenie@uoguelph.ca;

Astrid Schwalb (Co-Presenter/Co-Author)
Texas State University, schwalb@txstate.edu;

Abstract: Functional trait-based approaches have long been used in ecology to gain additional insights into patterns and processes but has rarely been applied to longer-lived and sessile aquatic taxa, such as freshwater mussels, to understand how the response of their community composition to environmental heterogeneity changes with spatial scale. We used freshwater mussels to examine how community composition changes in response to different environmental factors both within and between different segments of a river. We collected spatially extensive distribution data in three 20-km segments (upstream, midstream, downstream) in the San Saba River, Texas. As predicted by the network position hypothesis, local environmental variables explained significantly more of the variation in the functional composition in the upstream compared to the downstream segment. Regional environmental variables explained the highest amount of variation between segments. The functional-based approach explained up to 17% more of variation in the distribution of mussels compared to the taxonomic level approach. Our results suggest that stochasticity may play a larger role for species composition, whereas functional composition is more predictable, especially changes between up- and downstream.

Mourine Yegon (Primary Presenter/Author)
University of Eldoret, Kenya, mourineyegon@gmail.com;

FRANK MASESE (Co-Presenter/Co-Author)
UNIVERSITY OF ELDORET, f.masese@gmail.com;

Augustine Sitati (Co-Presenter/Co-Author)
University of Alabama, ansitati@crimosn.ua.edu;

Wolfram Graf (Co-Presenter/Co-Author)
University of Natural Resources and Life Sciences, Vienna, Austria, wolfram.graf@boku.ac.at;

Abstract: Macroinvertebrates play a unique role in aquatic ecosystems by acting as processors of nutrients and organic energy from allochthonous and autochthonous sources. Within East Africa and especially Kenya, rapid anthropogenic influence of deforestation and expansion of agricultural lands is currently progressing. This study investigated land use vs. altitudinal shifts in functional composition of macroinvertebrates within the Mt. Elgon catchment in Western Kenya. Twenty sampling sites within forested and agricultural areas, located in different elevations were sampled for physico-chemical water parameters and macroinvertebrates. Significant (p < 0.05) spatial variation was observed in total suspended solids, coarse particulate organic matter, temperature, and electrical conductivity between forested and agricultural sites with higher values recorded in agricultural streams. Temperature, conductivity and coarse particulate organic matter significantly varied across the elevational gradients. Higher shredder biomass and abundance occurred in forested streams in higher elevations than in low elevation agricultural streams. There was significant increase in abundance, taxon richness and biomass of specific functional feeding groups with increasing elevation. Lack of significant interactions between elevation and land use indicated that the elevational gradient played a greater role in influencing the composition of macroinvertebrates in these streams.

Daniela Cortes Guzman (Primary Presenter/Author)
Universidad Nacional Autónoma de México, dacortesgu@unal.edu.co;

Javier Alcocer (Co-Presenter/Co-Author)
Universidad Nacional Autónoma de México, jalcocerdurand@gmail.com;

Kenneth W Cummins (Co-Presenter/Co-Author)
Michigan State University, kc8161@gmail.com;

Abstract: The functional feeding groups (FFGs) approach to classify aquatic macroinvertebrates is extensively used in stream ecology. The FFGs classification combines morphological and behavioural adaptations of the organisms that link them to their food resources. Consequently, changes in the ecosystem that modify the food resource availability can be represented by FFGs. Merritt et al. (2002, 2017) proposed using FFGs proportions as surrogates for five ecosystem attributes across geographical regions. A set of 31 neotropical, 55 paleotropical and 37 temperate first-order streams was used to calculate the ecosystem attributes. All streams had a predominance of transported over the deposited organic matter and stable substrates. Neotropical and paleotropical streams were more heterotrophic, had a weaker association with the riparian environment, and a stronger predation control than temperate streams. Because biomass is usually a better predictor of ecosystem function than abundance, we compared the ecosystem attributes calculated as abundances plus biomass in one neotropical and one temperate stream. The attributes of both streams had significant (7 to 91%) differences. The use of FFGs proportions as surrogates for ecosystem attributes is a valuable tool for evaluating key ecological aspects and differences between geographical regions.

Augustine Sitati (Primary Presenter/Author)
University of Alabama, ansitati@crimosn.ua.edu;

ALFRED ACHIENG (Co-Presenter/Co-Author)
UNIVERSITY OF ELDORET, alfredachieng@yahoo.com;

FRANK MASESE (Co-Presenter/Co-Author)
UNIVERSITY OF ELDORET, f.masese@gmail.com;

Abstract: This study investigated the suitability of abundance- vs. biomass- based metrics of macroinvertebrate functional feeding groups (FFGs) as surrogates of ecosystems attributes of the Sosiani-Kipkaren River in western Kenya. A total of 21 sites were sampled during the wet and dry seasons along stream size and land use gradients. Macroinvertebrates were classified into five FFGs and used to derive the five metrics used as surrogates of ecosystem attributes.Taxon richness, abundance and biomass of shredders were higher in forested sites, whereas collectors dominated agricultural and urban sites. As expected, scrapers were numerically dominant in mid-order streams. Abundance-based metrics were better predictors of ecosystem attributes, and displayed greater response to changes in stream size than biomass-based metrics. Moreover, there was incongruence between abundance- and biomass-based indicators for P/R and CPOM/ FPOM. Catchment land use did not influence metric performance, suggesting that reach scale influences played a predominant role in structuring communities and determining ecosystem functioning. Although the use of FFGs as indicators of ecosystem integrity and functioning in this river show promise, lack of agreement between abundance- and biomass-based measures suggest that more studies are needed to refine the metrics used.

David Fleshman (Primary Presenter/Author)
Missouri State University , fleshman33@live.missouristate.edu;

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

Abstract: Gravel-bed streams have substantial hyporheic exchange, with downwelling zones typically occurring at riffle heads and upwelling zones at riffle tails. We collected invertebrates in upwelling and downwelling zones of a 2nd-order Ozark stream to ask how the patchy distribution of hydraulic conditions impacts spatial distribution of hyporheic invertebrate communities. Over a course of three months each in wet (Oct-Jan) and dry (June-Aug) seasons, we collected invertebrates and measured dissolved oxygen and organic matter in wells placed at three depths each at the heads and tails of three replicate riffles. Invertebrate abundance was high across all wells but varied seasonally (mean ~141 individuals/L in dry months and ~65/L in wet months), and both abundance and richness were greater in downwelling than upwelling zones across seasons and depths. Conversely, oxygen and organic matter did not vary consistently between upwelling and downwelling zones, and neither of these resources explained differences in invertebrate communities. These results suggest that hydraulic patterns alone might influence spatial distribution of hyporheic invertebrates in this stream. These findings demonstrate the importance of accounting for spatial and temporal variability when quantifying hyporheic assemblages at the reach scale.

Ryan Utz (Co-Presenter/Co-Author)
Chatham University, rutz@chatham.edu;

Alani Taylor (Co-Presenter/Co-Author)
US Army Corps of Engineers, miquela257@gmail.com;

Macie Chess (Co-Presenter/Co-Author)
Duquesne University, chessm@duq.edu;

Douglas Locy (Co-Presenter/Co-Author)
Aquatic Systems, Inc. , aquatic.systems@comcast.net;

Brady Porter (Co-Presenter/Co-Author)
Duquesne University, porterb@duq.edu;

Ian Hart (Primary Presenter/Author)
Chatham University, ian.hart167@gmail.com;

Abstract: The contemporary Ohio River mainstem is a heavily modified riverine habitat comprised of various reservoir-dam series and shaped channels, rather than a free-flowing system. However, many odonate species in such degraded habitats have been shown to prosper due to key life history attributes. In this study, we characterize the assemblage of odonates in a section of the Ohio River mainstem and also tested hypotheses on distributions in the channel. Samples were acquired as bycatch to benthic fish sampling conducted using electrified benthic trawling. We found seven odonate species, all of which were known to be species of conservation concern in one or more U.S. states. We also concluded that gradients of bank distance and river depth only weakly predicted odonate abundance, suggesting that the Ohio River species regularly use mid- channel habitat that is several meters deep. Life histories of most of the species collected are typical of those living in large lotic, and occasionally lentic, environments. Despite the substantial differences between contemporary and historic conditions of habitats in the Ohio River basin, an odonate assemblage worth conserving continues to be present in the mainstem channel.

Andrew Davidson (Co-Presenter/Co-Author)
Virginia Commonwealth University, davidsonat@mymail.vcu.edu;

William Shuart (Co-Presenter/Co-Author)
Virginia Commonwealth University, wshuart@vcu.edu;

Michael McCoy (Co-Presenter/Co-Author)
East Carolina University, mccoym@ecu.edu;

James Vonesh (Co-Presenter/Co-Author)
Virginia Commonwealth University, jrvonesh@vcu.edu;

Charles Stunkle (Primary Presenter/Author)
Virginia Commonwealth University, crstunkle@mymail.vcu.edu;

Abstract: In highly dynamic riverine landscapes, hydrologic connectivity and patch size are important components of landscape structure that underpin key processes that determine species abundance and richness across scales. However, responses to connectivity and patch size are dependent on species traits such as their modes of dispersal and life histories. We quantified the hydrologic connectivity of hundreds of riverine rock pools using a novel approach that combines remote sensing, historical river gauge data, and logistic regression. We modeled densities of two focal taxa, the Virginia river snail and skimmer dragonfly nymphs, in response to hydrologic connectivity (pool flood height, distance to channel, days since last flood), patch size (surface area, depth), and season using generalized linear mixed models. There were key differences in how each taxon responded to hydrologic connectivity with increasing pool flood height and distance to the main channel having a negative effect on snail densities, while dragonfly nymph densities increased with pool isolation. Snail densities increased with pool surface area but had no significant effect on dragonfly densities. Snails showed no difference in their temporal distribution across seasons, while dragonfly nymph densities were higher in summer and fall.

Katherine Abbott (Primary Presenter/Author)
University of Massachusetts Amherst, kmabbott@umass.edu;

Allison Roy (Co-Presenter/Co-Author)
U.S. Geological Survey, Massachusetts Cooperative Fish and Wildlife Research Unit, University of Massachusetts Amherst, aroy@eco.umass.edu;

Michael Cole (Co-Presenter/Co-Author)
Cole Ecological, Inc., mikebcole@comcast.net;

Kristopher Houle (Co-Presenter/Co-Author)
Massachusetts Division of Ecological Restoration, kris.houle@mass.gov;

Keith Nislow (Co-Presenter/Co-Author)
Northern Research Station, U.S.D.A. Forest Service, University of Massachusetts Amherst, keith.nislow@usda.gov;

Abstract: Across the northeastern US, small, obsolete dams impair natural stream dynamics by interrupting flows, altering habitats, and impacting water quality. Benthic macroinvertebrates may be particularly sensitive to changes in water quality, but studies linking dam-induced water quality impairments and macroinvertebrates are limited. We related water quality to macroinvertebrate compositional and functional metrics to understand mechanisms of biotic response and set expectations for restoration. We sampled macroinvertebrates within upstream, impounded, and downstream reaches in 12 streams across multiple years and collected corresponding continuous temperature and dissolved oxygen data. Dams varied in their water quality impacts, with downstream warming evident at 7 of 12 sites. Of those 7 sites, 5 exhibited a decrease in coldwater taxa downstream of the dam. Lotic assemblages were more correlated with catchment-scale factors (e.g., watershed size, percent forested; R2 = 0.64, 0.51) than with reach-scale water quality. Observed differences among reaches were primarily due to loss of common stream taxa in impoundments, resulting in stark assemblage differences. Results suggest biotic response to water quality impairments from dams may be overwhelmed by landscape-scale characteristics. Understanding the mechanisms of response may help prioritize and inform future dam removals.

Emma Rosi (Primary Presenter/Author)
Cary Institute of Ecosystem Studies, rosie@caryinstitute.org;

Emily Bernhardt (Co-Presenter/Co-Author)
Duke University, ebernhar@duke.edu;

Tyler Edwards (Co-Presenter/Co-Author)
Duke University, tge4@duke.edu;

Heather Malcom (Co-Presenter/Co-Author)
Cary Institute of Ecosystem Studies, malcomh@caryinstitute.org;

Nick Rodenhouse (Co-Presenter/Co-Author)
Wellesley College, nrodenho@wellesley.edu;

Audrey Thellman (Co-Presenter/Co-Author)
Univeristy of North Carolina at Chapel Hill, athellma@unc.edu;

Tammy Wooster (Co-Presenter/Co-Author)
CARY INSTITUTE OF ECOSYSTEM STUDIES, woostert@caryinstitute.org;

Abstract: Since the passage of the 1990 amendments to the US Clean Air Act, pH has steadily increased in streams at the Hubbard Brook Experimental Forest. Average pH has increased from below 5 in the 1960s to averaging near 5.5 today. We hypothesize that this increase in pH has led to a concomitant recovery of acid sensitive stream invertebrates such as caddisflies, stoneflies and mayflies. A compilation of benthic invertebrate studies from 1968 to present revealed that there are no long-term stream data sets using consistent techniques to examine whether recovery has occurred. During this same period, researchers at Hubbard Brook deployed Malaise traps to examine the numbers of insects available as prey for birds. We examined patterns in stoneflies and caddisflies in these long-term samples from 1972-present and found little evidence of significant increases in emerged stream insects during this period. Moreover, since 2018, we have deployed emergence traps adjacent to streams at Hubbard Brook and consistently find very few mayflies. Combined, these data suggest that macroinvertebrates are not showing significant signs of recovery from acid rain, despite increases in stream pH.

Joshua Benjamin (Primary Presenter/Author)
University of Florida, joshuaben3@gmail.com;

Abstract: Around the world, macroinvertebrates have been used in biomonitoring and aquatic restoration due to their great value in conservation. However, limited studies on macroinvertebrate community structure and abundance in East African rivers has precluded their use in biomonitoring these systems. Here, we aim to determine the abundance and distribution patterns of macroinvertebrate communities in Gura and Sagana rivers. We measured physicochemical parameters and sampled macroinvertebrates at 7 sites along the Gura River and 3 sites on the Sagana up and downstream of its confluence with the Gura. We counted and identified invertebrates to the lowest available taxonomic level. There was spatial variation in physicochemical parameters, including water temperature, pH, dissolved oxygen, turbidity, and electrical conductivity (p ? 0.05). In each river, macroinvertebrate abundance decreased from up - to downstream sites across all dominant orders (Ephemeroptera, Trichoptera, Coleoptera and Diptera), and cluster analysis revealed two main community clusters that differed from up- to downstream. The family Heptageniidae exhibited high abundance compared to other Ephemeroptera families in the upstream cluster. The characterization of these communities provides the first step for using macroinvertebrates in monitoring the quality in these two important Kenyan rivers.

Brett Landwer (Co-Presenter/Co-Author)
Missouri Department of Conservation, brett.landwer@mdc.mo.gov;

Alba Argerich (Co-Presenter/Co-Author)
University of Missouri-Columbia, argericha@missouri.edu;

Garrett Frandson (Primary Presenter/Author)
University of Missouri, gfdh4@umsystem.edu;

Abstract: Aquatic macroinvertebrates are crucial components of stream food webs and links between aquatic and terrestrial systems. In stream ecosystems, macroinvertebrate community structure is shaped by physical conditions including discharge, temperature, and substrate. Dams normally impose disruptions to all three of these conditions, making it difficult to separate the effects of any one of them on macroinvertebrates. Downstream of a reservoir on Missouri’s East Fork Black River, however, only substrate conditions dramatically differ between upstream and downstream reaches. Here we examine macroinvertebrate community structure and physical conditions at five riffles four sampling seasons. Sampling occurred in Fall 2017, Spring and Fall 2018, and Spring 2019. Substrate composition, flow velocity, and water depth show clear longitudinal trends. Preliminary results suggest macroinvertebrate abundance has a similar relationship, and there are clear seasonal and longitudinal differences in abundance among certain taxa. Substrate augmentation projects are aimed at providing conditions for desired macroinvertebrate and/or fish communities. The East Fork is a site for previous and future substrate augmentations; this study will inform what ratios of substrate sizes may be most beneficial for desired macroinvertebrate community structures and at what time of year to deliver them.

Emily Schilling (Primary Presenter/Author)
Augsburg University, schillin@augsburg.edu;

Kevin Kardynal (Co-Presenter/Co-Author)
Environment and Climate Change Canada, kevin.kardynal@canada.ca;

Holly Kundel (Co-Presenter/Co-Author)
University of Minnesota, kunde058@umn.edu;

Zephyr Crews-Erjavek (Co-Presenter/Co-Author)
Augsburg University, zephyr.crewserjavec@gmail.com;

John Zobitz (Co-Presenter/Co-Author)
Augsburg University, zobitz@augsburg.edu;

Keith Hobson (Co-Presenter/Co-Author)
University of Western Ontario, khobson6@uwo.ca;

Abstract: Investigating dragonfly migration is important for understanding species’ life history strategies, migratory connectivity, terrestrial-aquatic linkages, and for successful species conservation. We investigated the potential for migration of Aeshna canadensis using phenological observations in three study ponds in central Minnesota, 2017 – 2019. We also conducted probabilistic assignment to natal origins by measuring stable hydrogen isotope values of wing tissue of dragonflies collected in Minnesota and acquired through Canadian museum collections. This species emerged May – June from study ponds in central Minnesota, with a 10 – 15 week lag after emergence before mature adults were observed in late summer. The probabilistic assignment depictions of emerging tenerals overlapped with the sampling location, confirming accuracy of isotopic assignments of natal origin. Late-flying adults collected at our study ponds likely originated from southern Manitoba, suggesting a north-south migration pathway. We found further evidence for migration by analyzing wing tissue of adult dragonflies collected in northern Minnesota and south-central Canada. We provide the first conclusive evidence of Aeshna migration in North America and demonstrate a robust approach, combining field observations with stable isotope analysis, which can test for migration in other dragonfly populations.

H. Arthur Woods (Co-Presenter/Co-Author)
University of Montana, art.woods@mso.umt.edu;

Amanda L. Andreas (Co-Presenter/Co-Author)
University of Montana, amanda.andreas@gmail.com;

Priya Keller (Co-Presenter/Co-Author)
University of Montana, priya.keller@umconnect.umt.edu;

Emily L. Hamant (Co-Presenter/Co-Author)
University of Montana, emily.hamant@umconnect.umt.edu;

Alisha Shah (Co-Presenter/Co-Author)
University of Montana, alishas0624@gmail.com;

Rachel Malison (Co-Presenter/Co-Author)
Flathead Lake Biological Station, The University of Montana, rachel.malison@umontana.edu;

James I. Frakes (Primary Presenter/Author)
University of Montana, jameson.frakes@umontana.edu;

Abstract: Extracting sufficient oxygen from water is a difficult challenge for aquatic insects. This will likely be exacerbated by climate change, which is warming waters, decreasing levels of dissolved oxygen, and lowering flow rates in streams and rivers. Aquatic insects may offset some risks of warming temperatures by exhibiting physiological plasticity. We tested this hypothesis by measuring plasticity in respiratory and thermal tolerance phenotypes of giant salmonfly nymphs (Pteronarcys californica) in response to 3-week acclimations in the lab to different combinations of dissolved oxygen, temperature, and flow. During the acclimation period, we measured rates of growth and survival in two different experiments (temperature-oxygen interactions and temperature-flow interactions). Following experiments we measured changes to respiratory phenotypes characterized by upper thermal limits (CTmax), gill morphology, and metabolic sensitivity to hypoxia. Nymphs acclimated to hypoxic and warm water show reduced growth and survival, however, those that did survive had significantly higher upper thermal limits. Gill morphology and respirometry analyses are underway. These results indicate that physiological plasticity may provide some resilience in the face of climate change, although how effective such mechanisms will be in the wild remains unknown.

Namrata Giri (Primary Presenter/Author)
University of Texas at San Antonio(UTSA), namrata.giri@utsa.edu;

Abstract: Food resources for fish were analyzed in a creek undergoing urban development and wastewater inputs to understand whether food resources varied seasonally and spatially. Benthic organic matter and algal biomass was sampled in Cibolo Creek located in south-central Texas, below three tributaries-Currey, Menger, and Browns Creek. Currey and Menger are perennial streams carrying wastewater effluent, while Browns is a natural ephemeral stream. Summer season sampling was done during June6-20, 2019; fall season sampling was done during October22-24, 2019; winter season sampling was done during January14-23, 2020 and spring season sampling was done in March23 and 24, 2020. Fine particulate organic matter (FPOM), Ash Free Dry Mass (AFDM) for algae, Chlorophyll-a, and Coarse particulate organic matter (CPOM) did not differ significantly between sites within seasons. Sites below each tributary showed different seasonal patterns in food resources, which may be related to urban impacts such as wastewater effluent or urban runoff. However, only Menger differed significantly in FPOM, AFDM, and Chlorophyll-a between seasons. The findings will help to understand an adverse effect of urbanization on the creek which causes scarcity or a shift in types of food resources for fish.

Carolyn Cummins (Primary Presenter/Author)
The University of Georgia, carolynsc1225@gmail.com;

Amy Rosemond (Co-Presenter/Co-Author)
University of Georgia, rosemond@uga.edu;

Halvor Halvorson (Co-Presenter/Co-Author)
University of Central Arkansas, hhalvorson@uca.edu;

Amanda Rugenski (Co-Presenter/Co-Author)
University of Georgia, atrugenski@gmail.com;

Seth Wenger (Co-Presenter/Co-Author)
University of Georgia, sethwenger@fastmail.fm;

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

Vlad Gulis (Co-Presenter/Co-Author)
Coastal Carolina University, vgulis@coastal.edu;

Phillip Bumpers (Co-Presenter/Co-Author)
University of Georgia, bumpersp@gmail.com;

Nathan Tomczyk (Co-Presenter/Co-Author)
University of Georgia, nathan.tomczyk@gmail.com;

Abstract: Shredding insects are important consumers that determine the fate of detrital carbon (C) in streams. Shredders are vulnerable to rising stream temperatures, but detrital quality may modulate their thermal response via mechanisms that remain poorly understood. High carbon to nutrient (C:N) detritus may alleviate increased respiration costs at warmer temperatures, while low C:N detritus may relieve thermal stress. To investigate how temperature and food quality affect shredder physiology, we conducted an experiment at the Coweeta Hydrologic Lab (NC, USA). Individual stoneflies (Tallaperla sp.) were fed low (Acer) or high (Rhododendron) C:N litter in channels supplied with flowing water at 5 temperatures (ambient, +1C, +2C, +3C, +4C). We measured shredder growth, development, survival, and consumption rates over the 5-week experiment. Results from regression analyses suggest that insects in the higher temperature treatments experienced greater mortality (p<<0.01) and faster development rates (p<<0.01). Growth rates increased with temperature for insects fed Acer (p<0.05), but there was no such relationship for insects fed Rhododendron. Our results suggest that temperature may interact with food quality to alter shredder phenology and physiology. Such effects likely have implications for the fates of stream C as streams warm

John Olson (Co-Presenter/Co-Author)
Dept of Applied Environmental Science, California State University Monterey Bay, CA, USA, joolson@csumb.edu;

Cindy Matuch (Primary Presenter/Author)
California State, Monterey Bay, cmatuch@csumb.edu;

Abstract: Native freshwater mussels (Unionidae) are a vital species that play a significant role in maintaining water quality and healthy coastal ecosystems. However, North American freshwater mussel populations are drastically decreasing due to pollution, habitat loss, and introduced species, and have become a species of concern. Freshwater mussels, like the California Floater (Anodonta californiensis ), require a host fish to disperse their larvae, but which fish might be serving as hosts is unknown in central California. The discovery of a new population of California Floater at Fort Hunter Liggett provides an opportunity to determined which fish serves as host. This study will combine the use of field surveying techniques and laboratory experiments to evaluate potential host fish candidates for the California Floater’s larval stage. The results of the proposed work will identify the host fish species that disperse the California Floater in central California. This information can then be incorporated into a management approach that focuses on the recovery of the host fish and the diminishing California floater population.

Brianna Annaratone (Co-Presenter/Co-Author)
University of Arkansas, bhillebr@uark.edu;

Ashley Dowling (Co-Presenter/Co-Author)
University of Arkansas, adowling@uark.edu;

Daniel Magoulick (Co-Presenter/Co-Author)
Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, danmag@uark.edu;

Clay Prater (Co-Presenter/Co-Author)
University of Arkansas, prater.clay@gmail.com;

Michelle Evans-White (Co-Presenter/Co-Author)
University of Arkansas, mevanswh@uark.edu;

Camryn Larson (Primary Presenter/Author)
University of Arkansas, calarson@uark.edu;

Abstract: Plecoptera have an aquatic nymph and a terrestrial adult life stage, and as a result of climate change and habitat alteration, they are threatened globally. Capniidae, the most represented family of winter stonefly, contains multiple species of Allocapnia that are classified as being species of greatest conservation need by the Arkansas Wildlife Action Plan. We sought to compare the detection probability of Allocapnia species at nine sites in northwestern Arkansas using two methods: timed adult collection and timed nymph collection followed by rearing the nymphs to adults in the lab. Since Allocapnia adults are commonly found on emergent structures and leaves in streams, the timed adult collection focused on searching in these areas and collecting all adults. To collect nymphs, leaf packs and rocky areas were rinsed into a bucket, sieved, then picked out and brought to the lab to be raised to adults. A. rickeri, A. mohri, and A. jeanae were collected. Detection probability was estimated for each Allocapnia species found for both of the collection methods. We will be able to use results gathered to better inform future sampling and reduce bias in distribution or abundance estimates.

Ciashia Shiongyaj (Primary Presenter/Author)
Augsburg University, shiongyc@augsburg.edu;

Danelle Larson (Co-Presenter/Co-Author)
U.S. Geological Survey, dmlarson@usgs.gov ;

Emily Schilling (Co-Presenter/Co-Author)
Augsburg University, schillin@augsburg.edu;

Abstract: We investigated whether amphipod abundance differs spatiotemporally within two adjacent ponds in east-central Minnesota. Amphipod abundance was estimated with benthic dipnet sweeps, conducted at ~9 sample points on five dates (Fall 2019). Within-pond abundance differed up to an order of magnitude among sample points. Abundance was more variable within a pond in September, but the variability and total amphipod counts declined linearly through October. Amphipod counts were maximized around 1.1-1.3m water depth and were not found in depths <0.6m. Amphipods were most abundant at sample sites with submersed aquatic vegetation but were also found at sites with decayed plants. We also found that the fishless pond had greater amphipod species richness and abundance than the one with fish (fishless: mean = 13 amphipods; with fish: mean = 3 amphipods), and amphipods were 32% larger in the fish-containing pond (fishless: mean = 9.0 mm and with fish: mean = 12.4 mm). Our results show that amphipod distributions may be partially explained by water depth, aquatic vegetation, fish presence, and sampling date. These factors should be considered when estimating amphipod abundance in ponds, for example, for waterfowl habitat restoration efforts.

Stella Li (Primary Presenter/Author)
University of California, Berkeley, stella56329@gmail.com;

Collette Christensen (Co-Presenter/Co-Author)
University of California, Berkeley, colletechristensen@berkeley.edu;

Patina Mendez (Co-Presenter/Co-Author)
University of California, Berkeley, patina.mendez@berkeley.edu;

Abstract: Species identification is required for biological and conservation applications, but remains challenging in entomology where specimens are small and require expert skills for identification. Geometric morphometrics may be an underexplored method for species identification but has been used in the literature alongside machine learning to identify botanical scans of leaves to species. Using bulk light trap samples from Curry Creek, Northern California, we scanned mounted wings of males and females from the caddisfly families Sericostomatidae and Hydropsychidae, identifying 38 and 45 landmark locations, respectively. Using Generalized Procrustes Analysis (GPA) and Principal Component Analysis (PCA) we determined differences in venation between species and sex. GPA identified the central crossveins in Sericostomatidae as having the most variation throughout all specimens for both fore and hind wings, and PCA highlighted sexual dimorphism, particularly in the central crossveins, where males had more reduced wing venation than females. For Hydropsychidae, tests likewise revealed variation largely in the central crossveins; PCA scores quantified at least 50% variation between wing landmarks, enough to distinguish species into three distinct clusters for the site. Future applications of this method may focus on identification using machine learning.

Macarena Rein (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), macarenareinotto@gmail.com;

Elizabeth Valentina Avila Hernández (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), gestionambiental.avila@hotmail.com;

Diamela Gianello (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER); Instituto de Investigaciones en Biodiversidad y Medioambiente (Consejo Nacional de Investigaciones Científicas y Técnicas - Universidad Nacional del Comahue) - Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), gianellodiamela@gmail.com ;

Irene Aguer (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), ireneaguer1@gmail.com;

Eduardo Chaves (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), chaveslalo@yahoo.com.ar;

Gimena Paredes (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), paredes.gimena@gmail.com;

Melina Celeste Crettaz Minaglia (Co-Presenter/Co-Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), crettaz.melina@uader.edu.ar;

Luciana Percara (Primary Presenter/Author)
Laboratorio de Indicadores Biológicos y Gestión Ambiental de Calidad de Agua (IBGA), Facultad de Ciencia y Tecnología de la Universidad Autónoma de Entre Ríos (FCyT-UADER), lucianapercara011@hotmail.com;

Abstract: Benthic macroinvertebrates (BM) are organisms used as bioindicators since their structure reflects disturbances in the environment. During 2012-2019, the distribution of BM in the lower-middle basin of the Gualeguaychú River was evaluated through sampling in 8 streams, 4 rural (SR), 2 periurban (SP) and 2 urban (SU), BM samples were taken from both margins and the center of the main channel using dredge and D-net. The organisms were taxonomically identified and its distribution was studied qualitatively using the Jaccard index with Principal Coordinate Analysis (PCoA), Cluster (C), and Similarity-Dissimilarity (SD). 75 taxa MB were found. The PCoA and C analysis concentrated the streams in two groups, SR and SP-SU. The SD analysis correlated the SRs by presenting more families of the phylum Arthropoda, and the SPs with the SUs by dominating families of the phylum Mollusca. MB they reflected a higher level of alteration in the SPs and SUs than in the SRs, by presenting fewer number families, predominating those tolerant to environments rich in organic matter, such as Planorbiidae, Cochliopidae, Ampullaridae, Sphaeriidae and Corbiculidae. BM were a tool that provided important information on the status of the monitored streams.

Erica Becker (Primary Presenter/Author)
Loyola University Chicago, ebecker@luc.edu;

Martin Berg (Co-Presenter/Co-Author)
Loyola University Chicago, mberg@luc.edu;

Abstract: Elodea canadensis was documented on the Copper River Delta (CRD) in southcentral Alaska in 1982 and is the state’s first aquatic invasive macrophyte. With its ability to propagate vegetatively and survive Alaska’s cold winters, Elodea is now a dominant macrophyte by percent cover in several ponds across the CRD. Fluridone is an aquatic herbicide commonly used to treat many nuisance aquatic macrophytes, including Elodea in ponds on the Kenai Peninsula, AK and the CRD. The goal of this study was to examine the indirect effects of fluridone on macrophyte-associated aquatic insect communities. Five ponds were sampled over two years and selected on the basis of Elodea presence/absence and fluridone treated/untreated. Aquatic insects were collected monthly during summers from beds of two native macrophytes (Nuphar lutea and Hippuris vulgaris) and invasive E. canadensis. Chironomidae were numerically dominant in all samples, however functional feeding group (FFG) composition differed among ponds and macrophytes. Elodea beds from fluridone-treated ponds had lower predator:piercer-herbivore relative abundances than native beds in treated ponds. Species richness in treated ponds significantly decreased in native and invasive macrophyte beds the first year post-treatment, whereas densities increased.

Matthew Green (Primary Presenter/Author)
Clemson University , mwgreen@g.clemson.edu;

John C. Morse (Co-Presenter/Co-Author)
Clemson University, jmorse@clemson.edu;

Nathan Arey (Co-Presenter/Co-Author)
Louisiana State University, narey1@lsu.edu;

Cathy Jachowski (Co-Presenter/Co-Author)
Clemson University, cjachow@clemson.edu;

Abstract: Physiographic ecotones are associated with shifts in geology, forest type, and anthropogenic land use, which may facilitate shifts in macroinvertebrate functional feeding groups (FFGs) in streams that traverse these boundaries. Although the ecology of these groups is well-studied in non-ecotonal regions, little is known of how these communities respond to changes in forest type, in-stream habitat, and biogeochemical processes associated with ecotones. Within a multi-model framework, we evaluated the effects of these variables on the relative abundance of shredder, collector, and scraper FFGs along a southeastern USA Piedmont-Sandhills ecotone representing a shift in deciduous to coniferous forest and change in hydrology. We found that shredder composition was best predicted by forest type, while collector and scraper composition was best predicted by in-stream habitat. Shredders responded negatively to increasing mixed deciduous and coniferous forest, while collectors responded positively to increasing dissolved oxygen and riffle velocity and negatively to decreasing physical habitat score. Scrapers, alternatively, responded positively to both increasing riffle velocity and pH. Our results indicate that ecotones are important filters of macroinvertebrate functional diversity between physiographic provinces, which has important implications for energy flow and trophic relationships in stream habitats.

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

Irene Sanchez Gonzalez (Co-Presenter/Co-Author)
University of Alabama, irene1sanchez@gmail.com;

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

Megan Kubala (Primary Presenter/Author)
The University of Alabama, medavis16@crimson.ua.edu;

Abstract: Freshwater mussels (Bivalvia: Unionidae) dominate benthic biomass in some aquatic systems, creating biogeochemical hotspots that control ecosystem structure and function through direct and indirect pathways. Mussel nutrient excretion can stimulate benthic primary production and alter algal species composition (i.e. ‘green food webs’ based on primary producers). In addition, excretion enhances respiration and decomposition rates (i.e. ‘brown food webs’ based on decomposers). Bioturbation by animals also alters nutrient dynamics by indirectly stimulating denitrification and microbial growth. Here, we used mesocosms to evaluate how monoculture and polyculture treatments of three phylogenetically distinct species of freshwater mussels influence nutrient dynamics of green and brown food webs. Our findings indicate that compared to controls without mussels, mussel treatments had increased levels of microbial activity on leaf litter, greater fungal biomass production, increased benthic chlorophyll concentrations, as well as greater sediment nitrogen removal potentials. Our results suggest that freshwater mussels have bottom-up effects on both brown and green food webs via microbial priming and nutrient regeneration. This study highlights how consumers impact ecosystem functions such as nutrient cycling, primary production, and decomposition through altering nutrient availability for both autotrophic and heterotrophic microbes.

Beatriz Antillón (Primary Presenter/Author)
Universidad de Costa Rica, beatriz.antillon@ucr.ac.cr;

Abstract: Knowledge about functional feeding groups (FFG) facilitates our understanding on trophic dynamics and energy flow. Abiotic variables such as canopy cover, current velocity and pool area can affect the composition of freshwater communities. The objective of this study was to determine how the previously mentioned abiotic factors influenced the FFG of macroinvertebrates in a neotropical highland habitat in Costa Rica. We expected to find collectors and detritivores in dense canopy covered areas; filters associated with high current velocity and predators in wider pools and generalists in every context. Ten pools in a first order stream were sampled using physical disturbance for 2 minutes, macroinvertebrates were collected in a fine mesh (<2 µm) and sorted into their respective feeding functional group. We evaluated the relationship between FFG and abiotic factors (i.e., canopy cover, current velocity and pool area) using a RLQ analysis. We found a positive effect of canopy cover on herbivores and scrappers; current velocity on generalists and collectors; pool area on predators, detritivores and filters. Although most of the groups did follow the predicted patterns those who didn’t might be explained by adaptability to habitat pressures.

Katie Vasquez (Primary Presenter/Author)
University of North Texas, katievasquez@my.unt.edu;

James Kennedy (Co-Presenter/Co-Author)
University of North Texas, james.kennedy@unt.edu;

Brent Bellinger (Co-Presenter/Co-Author)
Brent Bellinger, Ph.D., brent.bellinger@austintexas.gov;

Aaron Schad (Co-Presenter/Co-Author)
Aaron Schad , aaron.n.schad@usace.army.mil;

Abstract: Lady Bird Lake and Lake Austin are adjacent reservoirs in Austin, Texas with the primary functions of electrical power generation, flood control, and recreation. In 1999, the invasive submerged aquatic macrophyte (SAV), Hydrilla verticillata was observed in Lake Austin (upstream) where it established over the span of the lake, though never establishing in Lady Bird Lake (downstream). Management strategies to eradicate Hydrilla, involving the stocking of sterile Asian grass carp, Ctenopharyngodon idella, nearly eliminated hydrilla from Lake Austin, but also resulting in overgrazing of native SAV, giving rise to other nuisance species such as zebra mussels and harmful algae. SAV, in addition to facilitating nutrient uptake and retention, enhancing water clarity, stabilizing substrate, and attenuating wave energy, provides food and refugia for aquatic fauna. My research aims to understand the biological implications from the presence and absence of SAV in the two reservoirs by seasonally analyzing the macroinvertebrate community within different habitat regimes. Preliminary results indicate macroinvertebrate taxa diversity changes between sites and habitat regimes from upstream to downstream. This study shows the importance of SAV and will contribute to further management decisions in the City of Austin.

Colden Baxter (Co-Presenter/Co-Author)
Idaho State University, baxtcold@isu.edu;

Sawyer Finley (Primary Presenter/Author)
Idaho State University, sawyerfinley@isu.edu;

Abstract: In river networks, the complexity of the habitat mosaic supporting macroinvertebrates may mediate metacommunity dynamics, dictating not only community membership, but also how communities interact and combine at multiple spatial scales. Alpha diversity of communities may be influenced by the characteristics of the larger metacommunity, and these relationships may occur at nested scales in a river-network, with reciprocal consequences for gamma diversity. We evaluated the influence of spatial complexity on macroinvertebrate metacommunities in a free-flowing, 6th-order river network in the central Idaho wilderness. Mainstem and tributary habitats are arranged throughout this network into confluence “complexes”, areas where multiple confluences occur in close proximity. We sampled the mainstem and 4 such complexes (10 tributary and 12 mainstem sites), totaling 66 distinct habitat patches. We hypothesized that habitats combine to support increasingly diverse communities at both the confluence-complex and river-network scales. Using a combinatory analytical framework, communities were aggregated in a randomized, sequential, iterative fashion into simulated forms of increasingly complex habitat mosaics. Preliminary results suggest that gamma diversity at the confluence-complex and river-network scale benefits from an increasingly complex habitat mosaic that supports high beta diversity from species turnover among communities.

Brandon Sansom (Primary Presenter/Author)
U.S. Geological Survey, bsansom@usgs.gov;

Maura Roberts (Co-Presenter/Co-Author)
U.S. Geological Survey, mroberts@usgs.gov;

Dannise Ruiz Ramos (Co-Presenter/Co-Author)
U.S. Geological Survey, druizramos@usgs.gov;

Nathan Thompson (Co-Presenter/Co-Author)
U.S. Geological Survey, nthompson@usgs.gov;

Ty Helmuth (Co-Presenter/Co-Author)
U.S. Geological Survey, thelmuth@usgs.gov;

Katy Klymus (Co-Presenter/Co-Author)
U.S. Geological Survey, kklmyus@usgs.gov;

Robb Jacobson (Co-Presenter/Co-Author)
U.S. Geological Survey, rjacobson@usgs.gov;

Abstract: Environmental DNA (eDNA) is an emerging tool in conservation used for species detection, but eDNA dynamics within aquatic ecosystems, especially transport and degradation, remain poorly understood. Moreover, it remains difficult to relate eDNA concentrations to biomass or distance to the population source. In this study, we developed one- and two-dimensional hydrodynamic and water quality models to examine the longitudinal and transverse transport of freshwater mussel eDNA in the Big Piney River in the Ozarks Highlands region of southern Missouri. We collected high resolution bathymetry and topography data to generate the model geometry along a 2 km river reach. We also collected water surface profiles, discharge, and cross-channel velocity to calibrate and validate the hydrodynamic model. We then coupled the validated hydrodynamic model with a water quality model to simulate the longitudinal and transverse transport and degradation of eDNA from a federally endangered mussel, Cumberlandia monodonta. The simulated results were compared to eDNA field measurements at several locations downstream from a C. monodonta population. The results of this study will help improve the understanding of eDNA fate and transport in aquatic environments and provide insight to relate eDNA to population metrics.

Maricela Alaniz (Primary Presenter/Author)
San Diego State University, maricela.n.alaniz@gmail.com;

Abstract: Climate change models have projected a decrease in precipitation across numerous regions of the world, highlighting the need to study the effects of low rainfall on freshwater ecosystems. In 2015, the Caribbean island of Puerto Rico experienced the most severe drought within the past 5 decades, providing an avenue to assess how freshwater macroinvertebrate assemblages respond to drought. We analyzed quantitative macroinvertebrate data (2014-2015) by using multiple biotic indices: the Biological Monitoring Working Party (BMWP-PR), Family Biotic Index (FBI-PR), percent Ephemeroptera and Trichoptera taxa richness, and percent dominance. We correlated monthly discharge to the index values for each sampling date. The dominance of tolerant taxa increased in the drought group and index values fluctuated as hypothesized for both groups, excluding BMWP-PR values. However, none of these differences were statistically significant except for the FBI-PR values in pools, and no significant correlations were found between discharge and all indices. We propose that these results may show evidence of macroinvertebrate adaptation to a wide range of flows. Given projected increases in drought frequency due to climate change, future studies can evaluate how freshwater ecosystems may be altered by potential regime shifts.

Zachary Tipton (Primary Presenter/Author)
University of Arkansas - Fayetteville, ztipton@uark.edu;

Brianna Annaratone (Co-Presenter/Co-Author)
University of Arkansas, bhillebr@uark.edu;

Camryn Larson (Co-Presenter/Co-Author)
University of Arkansas, calarson@uark.edu;

Clay Prater (Co-Presenter/Co-Author)
University of Arkansas, prater.clay@gmail.com;

Ashley Dowling (Co-Presenter/Co-Author)
University of Arkansas, adowling@uark.edu;

Daniel Magoulick (Co-Presenter/Co-Author)
Arkansas Cooperative Fish and Wildlife Research Unit, University of Arkansas, danmag@uark.edu;

Michelle Evans-White (Co-Presenter/Co-Author)
University of Arkansas, mevanswh@uark.edu;

Abstract: Stoneflies are a globally-threatened aquatic insect order that is sensitive to declining habitat and water quality. The West Fork of the White River (WFWR) watershed in Northwest Arkansas has historically (mid-80’s) contained a high number of winter stonefly Allocapnia species including the endemic, A. jeanae, now a species of concern due to intensive urbanization. The river, which serves as a major drinking water source for Northwest Arkansas, made the 303d list in 1998 due to poor water quality; several restorations have occurred or are planned along the river. Our study objective was to describe Allocapnia spp. occurrence along the WFWR across an increasing gradient of urbanization. We collected adult stoneflies at 6 sites from January through March 2021 from the headwaters of the mainstem to where it enters south Fayetteville. Sites were visited once a week during this period and specimens were collected for 20-minutes during each visit from riparian cobbles, leaf litter collections and woody debris. We found A. rickeri and A. mohri at all sites with A. jeanae appearing at only the most upstream site. This study can help guide restoration and management on the WFWR.

Sawyer Finley (Co-Presenter/Co-Author)
Idaho State University, sawyerfinley@isu.edu;

Colden Baxter (Co-Presenter/Co-Author)
Idaho State University, baxtcold@isu.edu;

Lauren Stidham (Primary Presenter/Author)
Idaho State University, stidlaur@isu.edu;

Abstract: In a wilderness stream network in central Idaho, USA, changing climate may be directly or indirectly influencing populations of the stonefly Yoraperla brevis (Peltoperlidae). Monitoring of two headwater streams in late-summer for the last 33 years indicates Y.brevis has gone from being scarce or undetectable to peaking in abundance during the mid-2000s, then dropping to nearly undetectable numbers shortly thereafter. Prompted by these observations, in tandem with a macroinvertebrate community study we conducted a synoptic survey of 20 tributaries and 12 mainstem sites to assess the distribution, abundance, and habitat conditions of Y.brevis. Y.brevis were found in only 9 sites; as expected these were 1-3rd-order tributaries. Among small streams, Y.brevis were found in those that were cold, perennial (usually springfed), and had a preponderance of moss-covered substrate. Some streams, though small and cold, did not have a mossy substrate; these lacked Y.brevis populations. We speculate that the changes revealed by long-term monitoring may be caused by climate-driven flow alterations (including drying), bedload movement, and resulting damage to mossy habitat. For some streams, earlier emergence may also be influencing detection of larvae during summer-time surveys.

Colden Baxter (Co-Presenter/Co-Author)
Idaho State University, baxtcold@isu.edu;

Kevin Fitzgerald (Co-Presenter/Co-Author)
University of Alaska Fairbanks, kevinfitz101@gmail.com;

Heath Goertzen (Co-Presenter/Co-Author)
N/A, heathgoertzen@gmail.com;

Keeley MacNeill (Co-Presenter/Co-Author)
Oregon State University, keeleymacneill@gmail.com;

Dana Warren (Co-Presenter/Co-Author)
Oregon State University, dana.warren@oregonstate.edu;

Jeremy Brooks (Primary Presenter/Author)
Idaho State University, broojer2@isu.edu;

Abstract: Benthic macroinvertebrate studies typically rely on preserving samples for later lab identification, reducing field-collection time but extending lab-processing time. Dead invertebrates become harder to detect, particularly in samples with excess detritus, lose distinguishing coloration and behavior, and are frequently damaged during preservation and transport. Here, we compare the efficiency and accuracy of processing macroinvertebrate samples in the field versus lab. In Yellowstone National Park, we sampled macroinvertebrates from eight headwater-streams. In the field, we used two-stage subsampling, the same observers measured and identified organisms (typically to Family-level), and identifications were later lab-verified. A subset of samples were solely lab-processed. Both field and lab-processing were timed to compare efficiency and accuracy. In general, field-processing was more efficient, and biomass estimates and identification accuracies were similar. Some challenging taxa were misidentified, highlighting the importance of vouchering. Studying preserved specimens alone abstracts taxonomy from context especially important to ecological learning by students. Additionally, field processing saves resources (e.g. EtOH, plastic bags) and minimizes invertebrate sacrifices. Subsequent, fine-level taxonomy beyond what is possible streamside is often necessary, but our findings suggest dedicating more time to field-processing may be more efficient, educational, and engaging.

Tessa Durnin (Co-Presenter/Co-Author)
University of Minnesota, Twin Cities, durni018@umn.edu;

Bruce Vondracek (Co-Presenter/Co-Author)
Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota - Twin Cities, bvondrac@umn.edu;

Leonard C. Ferrington, Jr. (Co-Presenter/Co-Author)
University of Minnesota, ferri016@umn.edu;

Corrie Nyquist (Co-Presenter/Co-Author)
Lund University, Sweden, nyqui095@alumni.umn.edu;

Hannah Bodmer (Primary Presenter/Author)
University of Toronto Mississauga, hannah.bodmer@mail.utoronto.ca;

Abstract: Diamesa species are cold-adapted non-biting midges that are an important ecological component in groundwater-fed stream ecosystems. These ecosystems may be adversely affected by climate change as average winter air temperatures increase and cause ambient temperature spikes. Adult midges were collected off the snow (n=298) from two sites on Pickwick Creek, a groundwater-fed trout stream in Winona County, MN on January 4th, 2021 to determine how short-term warm temperature exposure affects Diamesa. Control groups for both sites were incubated at constant 6°C, whereas treatment groups were exposed to 22°C for 24hrs and 48hrs. Short-term exposure to 22°C reduced the mean longevity of treatment groups at both sites (male longevity: 24hrs=14.2 and 12.9 days; 48hrs=12.4 and 11.3 days) compared to control groups (male longevity: 15.2 and 16.4 days for males). Larval hatch rate was also impacted by short-term warm temperature exposure: 67-80% of egg masses hatched at 6°C, 20-45% of egg masses hatched at 22°C for 24hrs, and 40-44% of egg masses hatched at 22°C for 48hrs at both sites. Thus, warm temperatures in winter caused by climate change could have long term effects on Diamesa populations.

Leslie Hatch (Primary Presenter/Author)
Missouri State University , Leslie614@live.missouristate.edu;

Indigo Tran (Co-Presenter/Co-Author)
Missouri State University , trangtran.indigo@gmail.com;

La Toya Kissoon-Charles (Co-Presenter/Co-Author)
Missouri State University , LKissoon@Missouristate.edu;

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

Abstract: Historical lead mining led to persistent metal contamination in Big River watershed (southeastern MO). Research of the effects of mining in Big River focused primarily on geomorphological changes and impacts on fish and mussels, but rarely included vegetation and macroinvertebrates. We found that sycamore trees growing on a gravel bar downstream of mining contamination had higher metal concentrations than trees upstream. Lead concentrations were higher in bark, stem, and leaves. Fallen leaves are a major source of carbon for aquatic macroinvertebrates, which become terrestrial as winged adults. These leaves can be a source of metals to the river ecosystem. We placed leaf packs (7mm mesh) containing contaminated and non-contaminated sycamore leaves in Big River over a 14-week period. We placed a randomized combination of leaf packs in riffles upstream and downstream of mining-contamination. Every two weeks, leaf packs were processed and analyzed to measure leaf mass loss and macroinvertebrate diversity and abundance. We investigated how metal content of leaf litter and stream reaches affect shredder abundance and how this subsequently affects leaf decomposition. Preliminary results showed a lower number of total shredders colonizing leaf packs downstream compared to upstream.

Brad Morris (Primary Presenter/Author)
Rivers Study Center and Department of Biology - University of Wisconsin La Crosse , morris.brad@uwlax.edu;

Ross Vander Vorste (Co-Presenter/Co-Author)
Rivers Study Center and Department of Biology - University of Wisconsin La Crosse , vandervorste.ross@gmail.com;

Abstract: Large rivers transport nutrients and energy from aquatic to the terrestrial ecosystems via insect emergence. In addition, these rivers provide diverse habitats, ranging from main channel to floodplain, and dynamic environmental conditions. However, little is known about how spatial and temporal variability influences insect emergence. In the study, we quantified spatial and temporal variability in insect emergence diversity and abundance across Pool 8 of the Upper Mississippi River near La Crosse, WI, USA. Physicochemical data and insect emergence were collected at nine different sites, that varied in distance from main channel (far, mid, close). Dissolved oxygen levels were elevated in the far distance sites compared to the close and mid distance sites, however, there were no differences in temperature, pH, and conductivity. Preliminary results of emergence (n=14) suggest community diversity and evenness are affected by distance from main channel. Future processing of samples will aim to quantify peaks in emergence timing. Identifying hotspots and hot moments in insect emergence will help managers better promote and protect this important aquatic-terrestrial transfer of energy.

Irene Sanchez Gonzalez (Primary Presenter/Author)
University of Alabama, irene1sanchez@gmail.com;

Garrett Hopper (Co-Presenter/Co-Author)
Department of Biological Sciences, University of Alabama, gwhopper@ua.edu;

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

Jamie Bucholz (Co-Presenter/Co-Author)
The University of Alabama, jbucholz@crimson.ua.edu ;

Abstract: Resource partitioning among co-occurring species has been a subject of interest to ecologists and is the main mechanism explaining niche differentiation across ecosystems. Freshwater mussels (Family: Unionidae) are a highly diverse and imperiled group of filter-feeding bivalves but have various functional traits that may drive interspecific resource assimilation differences. Mussels live in multi-species aggregations where resource partitioning may promote coexistence. Our goal was to determine mussel species isotopic niche area and overlap and evaluate if patterns of resource partitioning were consistent among sites and rivers. We used stable isotope analysis (?13C and ?15N) to evaluate niche width and overlap of 23 species and assessed spatial and interspecific differences in isotopic area in 15 sites in the Mobile and Tennessee river basins. Our findings suggest that despite some isotopic niche overlap between species, mussels partition trophic resources in these multi-species aggregations. Isotopic niche area among species varied spatially suggesting trait variability along environmental gradients and communities. To further understand spatial variation in niche breadth we propose to assess the relationship between community species richness and isotopic niche area.

Héctor Esparra-Escalera (Primary Presenter/Author)
Wayne State University, hector.esparra@wayne.edu;

Donna Kashian (Co-Presenter/Co-Author)
Wayne State University, dkashian@wayne.edu;

Abstract: Urbanization affects stream ecosystems by disrupting natural processes including hydrogeology, nutrient fluxes, and trophic dynamics. We seek to identify the role of riparian cover on periphyton biomass, and diversity of benthic macroinvertebrates at urban impaired stream sites in the Rouge and Huron rivers. Twelve stream sites were evaluated in recreational parks, near roads, and downstream of control sewer overflows. Measured parameters included riparian cover, chlorophyll-a and pheophytin from the biofilm, conductivity, and flow rate. Benthic macroinvertebrate communities were assessed, and indices including Ephemeroptera, Plecoptera, and Trichoptera (EPT), Hilsenhoff (HBI), Stream Quality (SQI), and diversity metrics were calculated. Preliminary results indicate differences in tolerant macroinvertebrate assemblages between urban streams based on riparian cover, and impairment level (SQI). Conductivity was negatively correlated with pheophytin, suggesting low herbivory and poor organic matter at sites with less riparian cover. Higher macroinvertebrate diversity was correlated with a higher density of riparian cover and lower chlorophyll-a. Park sites, despite being part of the urban streams assessed, were of higher quality and perhaps more resistant to disturbance impacts than other stretches of both streams in more developed areas.