SFS Annual Meeting

6/04/2024  |   13:30 - 13:45   |  Freedom Ballroom H/G

DNA METABARCODING REVEALS SPATIOTEMPORAL PATTERNS OF INVERTEBRATE DIVERSITY IN A NON-PERENNIAL HEADWATER STREAM Small headwater streams are ubiquitous in the southeastern U.S.A. and make disproportionate contributions to biodiversity and ecosystem function. Depending on environmental context, many experience contraction during portions of the year, resulting in reduced flow or drying. We used DNA metabarcoding to examine invertebrate diversity patterns across varying spatiotemporal scales within a small (0.98 km2), forested headwater catchment in Alabama, U.S.A. during an exceptionally wet year (October 2021 to January 2023) that encompassed a contraction event (October 2022). We related diversity differences with flow variability, water quality, and habitat type. We collected high-resolution temporal data at the stream outlet every 3 weeks, seasonal samples (March, June, August, January) at seven sites within the network, and a single synoptic sampling event covering 27 sites (June). The single synoptic event captured the greatest gamma diversity (127 taxa), followed by seasonal (116), and temporal sampling (112), highlighting the importance of spatial habitat variation. Richness and local contribution of richness to beta diversity decreased with distance from the outlet; however, two sites near a beaver pond in the middle of the watershed had the highest species richness during both the synoptic and seasonal samples, suggesting its importance both as a refugium from drying and contributor to habitat diversity. Rare taxa tended to be located in the smaller tributaries, which generally had lower diversity. By considering spatial and temporal variation simultaneously, our study provides insights into the patterns and processes that drive species richness in these ubiquitous landscape features.

Chelsea R. Smith (Primary Presenter/Author), The University of Alabama, crsmith5@crimson.ua.edu;

Daniel Allen (Co-Presenter/Co-Author), Penn State, daniel.c.allen@psu.edu;

Alice Belskis (Co-Presenter/Co-Author), New Jersey Department of Environmental Protection, albelskis@gmail.com;

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

Michelle Busch (Co-Presenter/Co-Author), University of Kansas, m.h.busch@ku.edu;

Stephen Plont (Co-Presenter/Co-Author), The University of Alabama, plontste@gmail.com;

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

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6/04/2024  |   13:45 - 14:00   |  Freedom Ballroom H/G

Drying effects on aquatic fungi: Vignettes from North American non-perennial streams. Fungi play keystone roles in freshwater ecosystems, principally as decomposers. Most research on stream-inhabiting fungi comes from perennial streams, but over half of the world’s streams are non-perennial, periodically drying and re-wetting. To address this research gap, we investigated the effects of stream drying on fungal biodiversity and function using both exploratory and experimental approaches. In our exploratory approach, we surveyed fungal DNA from leaf litter, rocks, and sediments at 50 sites along a natural flow-permanence gradient in a non-perennial stream network (Konza Prairie, Kansas, USA). Fungal ITS metabarcoding and sequencing revealed significant effects of surface flow permanence (determined via in situ sensors) on fungal community composition, e.g., ‘aquatic’ lichens (Verrucariaceae) preferred rocks at drier sites (Spearman rho= -0.40, p<0.05). Decomposers previously identified as stream drying-resistant, including Alternaria spp. and Tetracladium marchalianum, were among the most abundant taxa in leaf litter. Fungal alpha diversity was not correlated with intermittency (p>0.05) but was negatively correlated with activity of lignin- and cellulose-degrading enzymes and phosphatase in submerged leaf litter (all p<0.01), suggesting negative net diversity effects. To experimentally determine drying effects on decomposition rates, we dammed and diverted flow in a non-perennial stream (Talladega National Forest, Alabama, USA) and deployed cotton-strip decomposition assays in the manipulated reach and an upstream reference reach before, during, and after flow reduction. Decomposition rates were lowered in emerged riffles, but recovered following flow restoration (full-factorial ANOVA, F4,178=12.8543, p<0.0001). This ongoing research contributes to the development of basic knowledge on microbiome structure and function in non-perennial streams.

Charles T. Bond (Primary Presenter/Author), University of Southern Mississippi, Charles.Bond@usm.edu;

Andrielle L. Kemajou Tchamba (Co-Presenter/Co-Author), University of Mississippi, akemajou@go.olemiss.edu;

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

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

Amy J. Burgin (Co-Presenter/Co-Author), University of Kansas, burginam@ku.edu;

Colin R. Jackson (Co-Presenter/Co-Author), University of Mississippi, cjackson@olemiss.edu;

Lydia Zeglin (Co-Presenter/Co-Author), Kansas State University, lzeglin@ksu.edu;

Kevin A. Kuehn (Co-Presenter/Co-Author), University of Southern Mississippi, kevin.kuehn@usm.edu;

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6/04/2024  |   14:00 - 14:15   |  Freedom Ballroom H/G

DNA METABARCODING REVEALS DRIVERS OF SPATIAL VARIATION IN MACROINVERTEBRATE RICHNESS ALONG A NON-PERENNIAL, MONTANE STREAM NETWORK Non-perennial streams, which do not flow continuously, represent over half of the stream length on Earth. While interest in these systems is growing rapidly, holistic ecosystem studies of non-perennial streams are still limited. Here we use DNA metabarcoding data to examine patterns in stream invertebrate diversity across a small, mountainous watershed in southeastern Idaho, USA. We sampled macroinvertebrates across 29 sites, coupling these collections with measurement of hydrological and biogeochemical variables. We found highest invertebrate diversity in perennial stream reaches. Additionally, we found no difference in diversity between non-perennial stream reaches with a connection to the groundwater table and those without, despite the effect of groundwater connections on flow duration after storm events. While non-perennial stream reaches tended to be more prevalent in higher-elevation headwaters, we found no relationship between elevation and species richness across the watershed. Sites that tended to be more non-perennial had a greater amount of fly (Diptera) larvae, while perennial sites were characterized by more sensitive taxa, such as mayflies, stoneflies, and caddisflies (Ephemeroptera, Plecoptera, and Trichoptera, respectively). We found that stream type (perennial vs ephemeral vs intermittent) had the greatest impact on macroinvertebrate diversity. As climate change and human demand for fresh water are driving perennial stream networks towards non-perennial flow, understanding controls on macroinvertebrate diversity is increasingly important for the management and conservation of river systems globally.

Michelle Busch (Primary Presenter/Author), University of Kansas, mhopebusch@gmail.com;

Chelsea Smith (Co-Presenter/Co-Author), University of Alabama, chelsea.smith@jonesctr.org;

Alice Belskis (Co-Presenter/Co-Author), New Jersey Department of Environmental Protection, albelskis@gmail.com;

Maggi Kraft (Co-Presenter/Co-Author), Idaho State University, maggikraft4@gmail.com;

Evan Bilbrey (Co-Presenter/Co-Author), Idaho State University, evanbilbrey@isu.edu;

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

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

Daniel Allen (Co-Presenter/Co-Author), Penn State, daniel.c.allen@psu.edu;

Amy Burgin (Co-Presenter/Co-Author), University of Kansas, burginam@ku.edu;

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6/04/2024  |   14:15 - 14:30   |  Freedom Ballroom H/G

Hydrological gradients affect facets of biodiversity in different ways across distinct organism groups Riverine ecosystems support a high concentration of Earth’s biodiversity. Alterations to river hydrologic regimes affect biodiversity patterns, but research is limited on how it determines patterns of different facets of biodiversity (taxonomic and functional) across distinct organism groups (fish and macroinvertebrates). With climatic extremes becoming more frequent and intense across the globe, understanding relationships between facets of biodiversity and hydrology is paramount. We characterized three tributaries across the Colorado River Basin of Texas into ‘dryer’, ‘intermediate wet’, and ‘wetter’. We then modelled taxonomic- and trait-based beta diversity (and its components replacement (turnover) and richness-difference (nestedness)) of fish and macroinvertebrate communities along this hydrological gradient. Fish communities were taxonomically more dissimilar at the dryer tributary and functionally more dissimilar at the wetter. On the other hand, macroinvertebrate communities were both taxonomically and functionally more dissimilar at the wetter tributary. Both facets of beta diversity were driven by replacement for macroinvertebrates, while for fish, both facets were primally driven by richness-difference. In addition, freshwater mussel abundance was significantly lower at the dryer tributary compared to the wetter tributaries, highest abundances were found in the intermediate wet tributary. Our findings partially support the hypothesis that drying increases taxonomic beta diversity of riverine communities as response to higher environmental heterogeneity. Following our expectation, taxonomic and functional variables showed distinct patterns across the hydrological gradients. The increased frequency and intensity of droughts could thus profoundly modify not only the structure of communities, but also the ecosystem functions they support.

Mariana Perez Rocha (Primary Presenter/Author), Texas State University , mperezrocha@gmail.com;

Eryl Eryl Austin-Bingamon (Co-Presenter/Co-Author), Texas State University, erylaustinbingamon@txstate.edu;

Miranda Sams (Co-Presenter/Co-Author), Texas State University, mdsams@txstate.edu;

Noah Santee (Co-Presenter/Co-Author), Texas A&M, noahthelefty22@tamu.edu;

Benjamin Schwartz (Co-Presenter/Co-Author), Department of Biology, Texas State University, San Marcos, Tx., bs37@txstate.edu;

Joshuah Perkin (Co-Presenter/Co-Author), Texas A&M University , jperkin@tamu.edu;

Weston Nowlin (Co-Presenter/Co-Author), Texas State University, wnowlin@txstate.edu;

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

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6/04/2024  |   14:30 - 14:45   |  Freedom Ballroom H/G

Comparing Biodiversity Responses to Drying: Europe vs. South America Drying river networks (DRNs) represent over half of river networks worldwide and their occurrence has increased due to global change. The responses to drying of biotic communities in DRNs have focused on Europe, North America, and Australia, whereas knowledge gaps remain in the Neotropics - some of the most biodiverse and threatened DRNs. Biodiversity responses to drying could differ in the Neotropics due to contrasted biogeographical history, different climatic and flow regimes. Here, we combined extensive datasets of invertebrate communities from Europe and the Neotropical regions, gathering 15 DRNs across 10 countries. We conducted multivariate analyses using diversity metrics along with environmental and spatial variables in a metacommunity framework, now recognised as crucial in understanding biodiversity in river networks. We show that, in both continents, perennial reaches exhibit greater local diversity when compared to non-perennial ones. Further, beta diversity was higher in non-perennial reaches, with a strong nestedness component. In both continents, spatial distances are pivotal in determining community composition. Our results indicate most of the knowledge gained from European DRNs in the past decade could be transferred to South America in spite of their biogeographical and climatic differences. These results could guide stakeholders in conservation efforts to preserve the rich aquatic biodiversity of the Neotropics threatened by global change.

Daniel Escobar Camacho (Primary Presenter/Author), INRAE, France, daniel.escobar-camacho@inrae.fr;

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

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6/04/2024  |   14:45 - 15:00   |  Freedom Ballroom H/G

Dry times in a wet country: how will future drought shape biodiversity in England’s ‘winterbourne’ streams? Non-perennial streams are widespread and diverse in cool, wet countries such as the UK. Here, the chalk streams of southern England are iconic rivers with ‘winterbourne’ headwater reaches that experience natural, seasonal dry phases. Winterbournes support high biodiversity including several rare, specialist insect species whose active aquatic life stages are carefully timed to coincide with wet phases, and whose desiccation-tolerant egg stages can persist in damp streambed sediments. Hydrological droughts can extend and intensify dry phases in non-perennial streams, and future droughts could be longer, more frequent, faster-onset, hotter and more intense—even in cool, wet England. This presentation will review the evidence that current and future droughts pose a risk to winterbourne biodiversity, including the specialist insect species that thrive in these dynamic non-perennial streams. We will also outline scenarios in which future drought could push winterbournes and other non-perennial streams over thresholds of vulnerability at which they experience persistent shifts to species-poor, non-functional states. We will propose management actions designed to enhance drought resilience and thus prevent such shifts. As drought extremity increases across global regions including the cool, wet UK, such actions are urgently needed to sustain specialist species within biodiverse communities in non-perennial streams. We hope that our different climatic perspective will generate discussion that advances session participants’ collective understanding of non-perennial stream ecology across climate zones.

Rachel Stubbington (Primary Presenter/Author), Nottingham Trent University, rachel.stubbington@ntu.ac.uk;

Judy England (Co-Presenter/Co-Author), Environment Agency, judy.england@environment-agency.gov.uk;

Romain Sarremejane (Co-Presenter/Co-Author), Nottingham Trent University, romain.sarremejane02@ntu.ac.uk;

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