SFS Annual Meeting

6/03/2024  |   13:30 - 13:45   |  Independence Ballroom C

Quantifying the performance of fine sediment methodologies for invertebrate bioassessment The ecological impacts of fine sediment deposition are an increasing global problem within river systems. The quantification of substrate quality in river systems is needed for monitoring programmes and bioassessment. There is a clear need for rapid and cost-effective methods that produce precise and accurate estimates of deposited sediment across different river types that relate to biological metrics for ecological assessment. In our study, we examined how river type, scale, replication of samples, and different quantitative methods effect estimates of deposited fine sediment. We compared the accuracy of five quantitative methods: a sediment resuspension technique, a portable turbidity meter, a turbidity tube, Wolman pebble counts and the McNeil core sampler to a visual estimation of fine sediment at the reach and the patch scale. Strong differences in fine sediment were found between erosional and deposition patches and between substrate composition categories (i.e., coarse, moderate and fine). All quantitative methods were significantly correlated with the visual estimation of fine sediment at the reach and the patch scale. However, fine sediment measured with the McNeil core sampler had the lowest whilst the sediment resuspension method had the highest correlation coefficient with fine sediment measured by visual estimations. Findings from our study strongly support the use of visual estimations of substrate composition and the use of differing quantitative methods for measuring fine sediment, which will be useful for monitoring programmes and ecological assessment.

Tory Milner (Primary Presenter/Author), Loughborough University, V.S.Milner@lboro.ac.uk;

Kate Mathers (Co-Presenter/Co-Author), Loughborough University, k.mathers@lboro.ac.uk;

Morwenna Mckenzie (Co-Presenter/Co-Author), Coventry University, M.Mckenzie@lboro.ac.uk;

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6/03/2024  |   13:45 - 14:00   |  Independence Ballroom C

The influence of riparian buffer width on insect emergence in forest headwater streams in British Columbia The management of riparian zones significantly influences adjacent aquatic habitats, particularly in the context of commercial logging. Factors like light exposure, organic matter, and nutrient inputs are significantly altered by tree removal. Riparian buffers are often used to mitigate logging's impact on freshwater ecosystems, but their effectiveness on insect emergence is limited. In south-western British Columbia's Malcolm Knapp Research Forest, logging activities carried out in 1998 offered an opportunity to study the effects of forest alteration on stream-dwelling insect communities. This study focused on the emergence of Ephemeroptera, Plecoptera, and Trichoptera (EPT) taxa following logging activities. Utilizing a Before-After-Control-Impact (BACI) approach, we examined insect emergence in thirteen streams treated with one of three riparian buffer widths (30-m, 10-m, and 0-m) in comparison to unlogged reference streams. Insects were captured at regular intervals over the three-and-a-half-year study period using 1 m² emergence traps. Results showed a significant decline in emergence rates of aquatic insects in harvested sites compared to reference streams (generalized linear mixed models), demonstrating the effect that logging activities have on aquatic insect populations within stream ecosystems. The impact varied among insect taxa and was less severe in streams with wider buffer zones. A 30-m buffer appeared to offer substantial protection for many species in the event of logging. This research contributes to understanding the ecological impact of streamside forest logging and highlights the importance of such knowledge in sustainable resource management.

Rose Griffith (Primary Presenter/Author), The University of British Columbia, rose.griffith@ubc.ca;

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6/03/2024  |   14:00 - 14:15   |  Independence Ballroom C

ADDRESSING DATA GAPS TO GUIDE THE DEVELOPMENT OF CONSERVATION ACTIONS FOR ARKANSAS CAPNIID STONEFLIES Globally, Plecoptera contains many taxa that are in decline, vulnerable, endangered, or extinct. Information about species distributions, habitat requirements, life history, and population status are required to determine if and what conservation actions are needed. The Ozark-Ouachita region in Arkansas, USA once had 12 species of Allocapnia winter stoneflies; five of these are currently listed as species of greatest conservation need (SGCN) in Arkansas. However, their populations have not been censused broadly in the state since the 1980’s, likely because there are no species keys for immatures and adults are not commonly collected. We surveyed 60 stream reaches across four Level-III ecoregions with high historic Allocapnia diversity (Ozark Highlands, Boston Mountains, Arkansas Valley, and Ouachita Mountains) in the winters of 2020-2023 to gage current distributions, examine factors affecting detectability and occupancy, and to collect specimens for genetic barcoding. We also examined species-specific threshold responses to landuse/landcover and used Maxent ecological niche modeling parameterized with historic records to model historic and future population distributions. Air temperature affected Allocapnia detection, and climate, landscape, and landuse variables differentially affected species occupancy estimates. We created a barcode tree for Arkansas 10 capniid species, enabling juvenile identification and species detection of most species in the state. Threshold analyses and Maxent models identified species-specific differences in historic and current Allocapnia distributions linked to climate and landuse/landcover variables. Future declines in some historically-common taxa are predicted, along with an increase in one SGCN taxa, suggesting that the development and implementation of species-specific conservation actions may be warranted.

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

Brianna Annaratone (Co-Presenter/Co-Author), University of Arkansas, briannahillebrand@gmail.com;

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

Sahar Rezaei (Co-Presenter/Co-Author), University of Arkansas, srezaei@uark.edu;

Zachary Tipton (Co-Presenter/Co-Author), University of Arkansas - Fayetteville, ztipton@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;

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6/03/2024  |   14:15 - 14:30   |  Independence Ballroom C

INFLUENCE OF LOW AND HIGH PRECIPITATION AND ROLE OF GEOMORPHOLOGY ON FRESHWATER INVERTEBRATE RESPONSE IN A TROPICAL STREAM Climate models agree that precipitation patterns for the Caribbean are expected to change, including extreme precipitation patterns. Unusual precipitation events lead to stream fragmentation during droughts or flooding during storms, impacting aquatic assemblages and habitat geomorphology. We aimed to 1) assess changes in precipitation patterns from 1975- 2022 in the Luquillo Experimental Forest, Puerto Rico, 2) determine macroinvertebrate responses at different precipitation levels, and 3) evaluate the influence of geomorphology on these patterns. We found that the number of low and high precipitation days has decreased significantly over time. However, intermediate precipitation values have been increasing since 1975. Also, the relationship between precipitation and the density and biomass of aquatic insects was taxa-specific. In contrast, average density and biomass for the whole assemblage showed a negative association with daily precipitation. Taxonomic diversity (Shannon’s H) indices significantly differed across pools based on the identified low and high precipitation periods. However, these patterns showed no apparent trend in relation to the pool volume. No significant relationships were found between dry period length and invertebrate density and biomass. We suggest that the controls exerted by precipitation patterns in tropical stream assemblages are taxa-specific and habitat-specific. A comprehensive understanding of how stream ecosystems respond to low or high precipitation and the role that geomorphology plays in these responses is critical to understanding their vulnerability to predicted changes in environmental conditions, particularly based on the observations that precipitation patterns have already shifted to more numerous intermediate precipitation events.

Mariely Vega-Gómez (Primary Presenter/Author), North Carolina State University, mvega2@ncsu.edu;

Alonso Ramírez (Co-Presenter/Co-Author), North Carolina State University, alonso.ramirez@ncsu.edu;

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6/03/2024  |   14:30 - 14:45   |  Independence Ballroom C

SUBSTRATE PREFERENCE AND ROLE OF SIMULATED DISTURBANCE IN PATTERNS OF MAYFLY DENSITY AND BIOMASS IN TROPICAL STREAMS OF PUERTO RICO Disturbances significantly impact larval aquatic insect distribution by displacing organisms downstream or altering the available resources and substrates in their habitat. Little is known about how frequent hydrological disturbances that alter the streams of the Luquillo Experimental Forest in Puerto Rico impact the dominant mayfly taxa, Cloeodes spp., Neohagenulus spp., and Borinquena carmencita. Our study aimed to 1) assess Ephemeroptera distribution within a Puerto Rican stream, 2) determine if the mayfly genera prefer habitats dominated by rock or leaf litter substrates, and 3) evaluate their response to substrate changes due to disturbance. To achieve this, we surveyed pool and riffle habitats weekly over five weeks and manipulated substrate composition in 12 plots for four weeks to mimic disturbance effects. To assess mayfly preference and the impact of substrate manipulation, we applied Spearman correlations and a modeling approach. Most mayflies (92%) were found in pools, mainly Cloeodes spp. (55%), with Neohagenulus spp. and B. carmencita also present in nearly equal numbers. Larger rock substrates correlated with lower mayfly densities, and no preference for leaf litter was noted. Water depth positively influenced biomass and density, while substrate manipulations did not significantly impact mayflies. We pose that the preferences exhibited by the Ephemeroptera taxa were likely driven by geomorphological aspects of the habitat that determine the available food sources, predator avoidance, and flow refugia. This study informs our understanding of mayflies’ preference for substrate and habitat and how hurricanes may alter their distribution.

Matthew Gilbert (Primary Presenter/Author), Wesleyan University, mjgilbert@wesleyan.edu;

Mariely Vega-Gómez (Co-Presenter/Co-Author), North Carolina State University, mvega2@ncsu.edu;

Alonso Ramirez (Co-Presenter/Co-Author), Department of Applied Ecology, North Carolina State University, alonso.ramirez@ncsu.edu;

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6/03/2024  |   14:45 - 15:00   |  Independence Ballroom C

Accounting for macroinvertebrate contributions to stream greenhouse gas emissions Inland waters are significant sources of greenhouse gas (GHG) emissions to the atmosphere, controlled by differing physical features, biogeochemical processes, and upstream contributions. However, the ecological significance of direct or indirect contributions to these emissions by macroinvertebrates remains unknown. Some, albeit sparse, evidence suggests that a few species of shredder and collector, due to the continued microbial activity in their anoxic guts, contribute to GHG flux from streams via direct emissions. We hypothesized that shredders, scrapers, and collectors would produce more methane (CH4) and nitrous oxide (N2O) than predators. In addition, macroinvertebrates inhabiting streams with high NO3 concentrations would have a greater direct emission of N2O. We conducted a field microcosm to investigate the direct contributions of different functional feeding groups of benthic macroinvertebrates to CH4 and N2O production in New Hope Creek (0.114 ± 0.001 mg/L NO3-N) and Ellerbe Creek (1.412 ± 0.031 mg/L NO3-N). We collected various taxa of invertebrates, stored, and incubated them in situ in gas-tight vials containing filtered stream water, and obtained point measurements every hour to monitor changes in GHG concentrations. We compared rates of emissions by macroinvertebrates to reach-scale emissions to estimate their relative importance to total GHG fluxes from streams. Given the abundance of benthic macroinvertebrates, findings from this study will help refine their direct contribution to stream C and N fluxes.

Nguyen Tien Anh Quach (Primary Presenter/Author), University of North Carolina at Chapel Hill, tienanhquachnguyen@gmail.com;

Amanda DelVecchia (Co-Presenter/Co-Author), University of North Carolina at Chapel Hill, amanda.delvecchia@unc.edu;

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