5/24/2016  |   10:30 - 10:45   |  308

DAMMED AND ADRIFT: PATTERNS OF INVERTEBRATE DRIFT THROUGHOUT COLORADO RIVER BASIN TAILWATERS Large dams impose a suite of physical, chemical, and hydrological changes on river ecosystems, particularly in the tailwater reaches that exist within the first several kilometers downstream of these dams. Nonetheless, surprisingly little is known about how tailwater invertebrate communities on the large rivers downstream of such dams may vary, and the conditions (imposed by the dam or otherwise) that influence this variation. In this presentation, we will focus on one critical component of invertebrate life history that is likely to be strongly influenced by dams: invertebrate drift. Using a spatially-extensive, repeat dataset spanning eight tailwaters throughout the Colorado River Basin in the Western US, we will explore patterns and processes in invertebrate drift over both space and time. Specifically, longitudinal recovery patterns of individual taxa and invertebrate communities will be discussed, as will seasonal patterns of invertebrate drift and the overall diversity of the tailwater invertebrate community, both within and across the eight tailwaters. These results will elucidate how and why invertebrate communities downstream of dams can vary, with implications for the conservation and management of tailwater riverine ecosystems.

Jeffrey Muehlbauer (Primary Presenter/Author), University of Alaska Fairbanks, USGS Alaska Cooperative Fish and Wildlife Research Unit, jdmuehlbauer@alaska.edu;


Ted Kennedy ( Co-Presenter/Co-Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, tkennedy@usgs.gov;


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5/24/2016  |   10:45 - 11:00   |  308

HOW FISH PREDATORS AFFECT PARASITE INFECTION WITHIN LARVAL ODONATES: TESTING THE ROLES OF HOST DENSITY, SPECIES IDENTITY, AND TRANSMISSION SUCCESS As top predators, fish can have expansive and strong effects across ecosystems, often including changes in both community composition as well as the behavior of potential prey. Emerging evidence has highlighted the potential for predator-mediated effects on patterns of parasitism, although in-depth tests of underlying mechanisms remain relatively rare. Here we investigated the effects of fish presence on the infection of odonate larvae by the trematode parasite Haematoloechus. Specifically, we assessed changes in infection mediated through shifts in host abundance, host species composition, and transmission success from intermediate snail hosts. Over the course of 2 summers, we quantified the presence and intensity of trematode metacercariae from 1612 odonate nymphs representing 13 genera from 15 ponds with fish and 27 sites without. We developed hierarchical models to explore the effects of fish on individual host infection patterns while incorporating the influence of nymphal odonate density, infected snail density, and their interactions as additional predictors. Our analysis revealed that while the presence of fish alone did not influence parasite prevalence or load there was strong interaction effects among different families and genera.

Travis McDevitt-Galles (Primary Presenter/Author), University of Colorado: Boulder, travis.mcdevittgalles@colorado.edu;


Pieter Johnson ( Co-Presenter/Co-Author), University of Colorado: Boulder, pieter.johnson@colorado.edu;


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5/24/2016  |   11:00 - 11:15   |  308

STOICHIOMETRY OF HOMEOSTASIS AND GROWTH ACROSS AQUATIC INVERTEBRATE DETRITIVORES Many stoichiometric models assume animals maintain fixed or strict homeostasis of body elemental composition. However, organism elemental content can change with resource stoichiometry or growth, and data from non-model taxa are greatly lacking. To assess the stoichiometry of homeostasis and growth (new tissue production), we fed maple or oak litter of variable carbon:nitrogen (C:N), carbon:phosphorus (C:P), and nitrogen:phosphorus (N:P) content to seven aquatic invertebrate detritivore genera from four orders (Isopoda, Plecoptera, Trichoptera, and Diptera) in the laboratory. Most taxa exhibited no response of body C:N or C:P to resource C:N or C:P (P>0.05), indicating strict homeostasis; however, 4 genera were loosely homeostatic in N:P content (P<0.05). Growth C:N diverged from initial body C:N in all 6 insect genera (P<0.05). Hemi- and non-metabolous genera often exhibited lower, declining C:N and C:P content whereas holometabolous genera often exhibited higher, increasing C:N and C:P over growth, likely due to differential investment in tissues such as wing muscle versus fat body. Our data reveal intra- and interspecific variation in elemental content of invertebrate detritivores toward improved stoichiometric models of animal growth and nutrient recycling.

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


Chris Fuller ( Co-Presenter/Co-Author), University of Central Arkansas, cfuller008@gmail.com;


Stephanie Stoughton ( Co-Presenter/Co-Author), University of Central Arkansas, stoughton54@gmail.com;


Thad Scott ( Co-Presenter/Co-Author), Baylor University, Thad_Scott@baylor.edu ;


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


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5/24/2016  |   11:15 - 11:30   |  308

VARIABILITY IN BENTHIC INVERTEBRATE COMMUNITIES IN A LARGE RIVER EXPLAINED BY PROCESSES OPERATING AT DIFFERENT SPATIAL AND TEMPORAL SCALES Factors affecting benthic invertebrate community structure in rivers include environmental conditions and biological interactions that vary across space and time to create patterns of heterogeneity and dynamic stability. Studying benthic invertebrate communities from large rivers might reveal factors governing taxonomic distribution and integrative biodiversity of rivers but requires intensive, quantitative sampling in challenging conditions across multiple habitat types. We explored benthic invertebrate communities from the Susquehanna River in several experiments, which collectively enable us understand how factors and processes important to community structure vary across space and time. Communities were most similar within individual years and at fine spatial scales or between sampling locations oriented parallel to flow. Local scale conditions, such as tributary confluences, microhabitat characteristics, and substrate traits, influenced patch-scale diversity and community structure. However, interactions among patches via dispersal or other mechanisms control metacommunity structure at the scale of reaches and river segments. Temporal controls on community structure seem to operate both within years and across years, depending on life cycles of certain taxa, introduction and spread of non-native species, and management activities across the watershed.

Matthew McTammany (Primary Presenter/Author), Bucknell University, mmctamma@bucknell.edu;


Matthew Wilson ( Co-Presenter/Co-Author), Susquehanna University, mjw029@bucknell.edu;


Nicole King ( Co-Presenter/Co-Author), Bucknell University, nrk005@bucknell.edu;


Jordan Barton ( Co-Presenter/Co-Author), Bucknell University, jab101@bucknell.edu;


Meghan Reilly ( Co-Presenter/Co-Author), Bucknell University, mer039@bucknell.edu;


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5/24/2016  |   11:30 - 11:45   |  308

IS SUBTERRANEAN BIODIVERSITY MEDIATED BY BURROWING CRAYFISH? Crayfish have been described as ecosystem engineers as a result of polytrophic feeding and sediment processing activities. Most work has occurred in surface waters, yet many species occupy terrestrial burrows. Little is known about burrowing crayfish; much less is known about the community structure of burrow co-inhabitants. Here we describe communities associated with burrows of Cambarus harti and identify potential predictors of community structure. Crayfish burrows contained multiple taxa representing various feeding strategies, including primary and secondary consumers, with densities of 20 to 2500 invertebrates/L in a given burrow. Burrows harbored a complex of microcrustaceans, worms, mites, and insects with contrasting feeding strategies including large dipteran predators in 75% of the burrows. Taxa richness was explained by burrow size and groundwater depth, with higher richness in larger burrows with near-surface water, while groundwater depth and distance to surface water were strong correlates of assemblage structure. These findings suggest positive relationships between per capita engineering activity and taxa richness, however such predictability may be context-dependent as a result of source proximity due to burrow placement.

Brian Helms (Primary Presenter/Author), Troy University, helmsb@troy.edu;


Jim Stoeckel ( Co-Presenter/Co-Author), Auburn University, jas0018@auburn.edu;


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5/24/2016  |   11:45 - 12:00   |  308

REGIONWIDE ANALYSIS OF MACROINVERTEBRATE ASSEMBLAGE STRUCTURE AND ITS RELATION TO HABITAT CHARACTERISTICS Biological communities are increasingly important for monitoring ecosystem health. In the Northwestern Great Plains (NWGP) ecoregion of South Dakota, benthic macroinvertebrate assemblages are poorly described. It is vital to evaluate these communities to help assess biotic integrity. In 2014 and 2015, 60 perennial wadeable stream reaches in eight level four ecoregions within the NWGP were visited to collect physical and chemical habitat data and benthic macroinvertebrate samples. Sixty-two families were represented, although Chironomidae (mean=41%, range=2-99%) generally comprised the highest percent abundance of invertebrates. Similarly, collector-gatherers (mean=69% abundance, range=7-99%) and burrowers (mean=43% abundance, range=2-99%) were the major functional feeding group (FFG) and habit guild. Family-level assemblage metrics differed significantly among the eight LIV ecoregions. The Sagebrush Steppe may be the most distinct with 16 significant differences from other ecoregions for nine separate assemblage metrics. Most of the metrics differentiating between ecoregions significantly correlated with stream width, discharge, specific conductance, and salinity. These preliminary results indicate that the NWGP is not biologically homogenous, and a subset of physical and chemical parameters may explain significant variation in biotic integrity.

Lyntausha Kuehl (Primary Presenter/Author), South Dakota State University Department of Natural Resource Management, lyntausha.kuehl@sdstate.edu;


Chad Kaiser ( Co-Presenter/Co-Author), South Dakota State University Department of Natural Resource Management, chad.kaiser@sdstate.edu;


Katie N. Bertrand ( Co-Presenter/Co-Author), South Dakota State University Department of Natural Resource Management, katie.bertrand@sdstate.edu;


Nels H. Troelstrup, Jr. ( Co-Presenter/Co-Author), South Dakota State University Department of Natural Resource Management, nels.troelstrup@sdstate.edu;


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