SFS Annual Meeting

5/20/2019  |   11:00 - 11:15   |  253 AB

MORE THAN THAT FOR WHICH YOU BARGAINED: WHY SAMPLING MATTERS IN POPULATION GENETICS Population genetic sampling runs the gamut from a large number of samples from a limited number of populations to a few individuals from a large number of populations. Sampling designs are often selected without consideration for life history traits and seldom account for historical migrations. Here, we present data from the semi-voltine Nigronia serricornis, showing that “one and done” sampling confounds our understanding of gene flow patterns due to the impact of historical migrations and lumping of multiple cohorts. Life history traits need to be considered when designing population genetic projects; especially if they are to inform management decisions.

Jeffrey Heilveil (Primary Presenter/Author), State University of New York, College at Oneonta, jeffrey.heilveil@oneonta.edu;


Emily Berezowski (Co-Presenter/Co-Author), State University of New York College at Oneonta, bereem98@oneonta.edu;


Emma Thompson (Co-Presenter/Co-Author), SUNY Oneonta, thomer54@oneonta.edu;


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5/20/2019  |   11:15 - 11:30   |  253 AB

FLEXIBLE LIFE HISTORY ESSENTIAL FOR THE MAYFLY, HEXAGENIA LIMBATA, TO SURVIVE IN WESTERN LAKE ERIE While the mass emergence of Hexagenia mayflies from Lake St. Clair during June & July of each year appears to be a regular event produced by 2 coexisting cohorts that require 22 months to develop from egg to adult, the same mass emergence of Hexagenia mayflies from the western Lake Erie occurs only because of the great flexibility in their life history. Cohorts in western Lake Erie show dramatic declines in abundance over some winters. Eggs laid by those few adults that emerge from August through October (i.e. stays) or during periodic mass fall emergences (2016, 2018) produce individuals that supplement depleted cohorts. Furthermore, individual growth rates significantly increase when one of the cohorts is low in abundance; so much so that individuals are able to reach maturity within one year (hatch in August and emerge the following June). The contribution of “stray” adults during the summer, adults from a fall emergence, and increased growth rates in response to reduced nymph abundance are essential to maintain an annual June-July emergence in the stressful environment of western Lake Erie.

Ronald Griffiths (Primary Presenter/Author), Oregon State University, Oregon Hatchery Research Center, Corvallis, OR 97331, ron.griffiths@oregonstate.edu;


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5/20/2019  |   11:30 - 11:45   |  253 AB

GENETIC DIVERSITY OF A VAGILE AQUATIC INSECT VARIES WITH RIVER NETWORK STRUCTURE Gene flow among populations is constrained by dispersal ability, habitat connectivity, and time. For aquatic organisms that disperse along stream corridors, habitat connectivity of a river network can thus define the boundaries of gene flow. In this study, we investigated the genetic diversity of a strong-dispersing caddisfly, Hydropsyche oslari, using mtDNA (CO1 gene) in the topologically diverse Colorado River Basin. We expected to find less genetic distance among H. oslari within the Upper Basin, which has a dense dendritic network of perennial tributaries, than among populations within the arid and sparse river network of Grand Canyon in the Lower Basin. The two basins are divided by Lake Powell, a >300 km long reservoir on the Arizona-Utah border in the southwestern United States. Consistent with predictions, we found that H. oslari within the Upper Basin shared more genetic similarities than H. oslari within Grand Canyon. Additionally, we found that populations in the Upper Basin and Grand Canyon were entirely genetically differentiated, indicating that these two populations were isolated thousands of years before the 1963 closure of Glen Canyon Dam and subsequent filling of Lake Powell.

Anya Metcalfe (Primary Presenter/Author), USGS Southwest Biological Science Center, Grand Canyon Monitoring and Research Center, ametcalfe@usgs.gov;


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


Jane Marks (Co-Presenter/Co-Author), Northern Arizona University, jane.marks@nau.edu;


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


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5/20/2019  |   11:45 - 12:00   |  253 AB

USING BIOENERGETICS AND POPULATION DYNAMICS MODELLING TO INFORM FISHERIES MANAGEMENT AT JOE’S VALLEY RESERVOIR, UTAH. Since 1999, over-abundance of the introduced non-game fish Utah chub (Gila atraria) in Joe’s Valley Reservoir has prompted concern over inter-specific competition with salmonid game species. Sterile hybrid top predators, splake (Salvelinus namaycush X Salvelinus fontinalis) and tiger muskellunge (Esox masquinongy X Esox lucius) were stocked in the lake to apply top-down pressure for control of the Utah chub population. Our goal was to evaluate the effectiveness of this biological control via consumption by tiger muskellunge, splake and Bear Lake cutthroat trout (Oncorhynchus clarki utah) while also maintaining chub as a forage species. An age-structured bioenergetics model was constructed for each predator species to estimate annual consumption of Utah chub. Using estimated vital rates, an age-structured matrix population model was constructed for Utah chub to evaluate population viability. We found that Utah chub in the reservoir were the primary forage for tiger muskellunge and splake, consuming 81.7% of the biomass of Utah chub annually. We found the asymptotic population growth rate (?) for Utah chub to be 0.923, indicating an annual decline of 7.7% in the population. Extinction probability analysis found the mean time to population extinction was 45.75 years.

Jack Dudding (Primary Presenter/Author), Utah Division of Wildlife Resources, jdudding@utah.gov;


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5/20/2019  |   12:00 - 12:15   |  253 AB

SPECIES DISPERSAL MEDIATES OPPOSING INFLUENCES OF A BRANCHING NETWORK ON GENETIC VARIATION IN A METAPOPULATION In nature, ubiquitous fractal networks can have two but opposing influences, by increasing distal and confluent habitats, respectively, under raising branching complexity on metapopulations’ genetic structure. In this study, we evaluated the integrated influences of network complexity and species dispersal mode/ability on genetic divergence among populations at the catchment scale, using a theoretical framework with empirical genetic data from four sympatric stream macroinvertebrate species. Empirical patterns of spatial genetic structure were attributed to dispersal ability and the species’ habitat specialisation levels. Our theoretical evidence showed that both greater landscape connectivity (via shorter watercourse distance) and greater isolation of distal habitats (e.g. headwater streams) occur in the more-branched networks. These two spatial features have negative and positve influences on genetic divergence, respectively, with their relative importance varying in different species. Downstream- and upstream-biased asymmetric dispersals dictate increases and declines, respectively, in genetic divergence. In addition, distal populations (e.g. in headwaters) have higher genetic independence between themselves under higher levels of downstream-biased asymmetry. A strong association between species features and evolutionary processes (gene flow and genetic drift) mediates the pervasive influences of branching complexity on metapopulation genetic divergence.

Ming-Chih Chiu (Primary Presenter/Author), Ehime University, Japan, mingchih.chiu@gmail.com;


Bin Li (Co-Presenter/Co-Author), Ehime University, Japan, binglee527@gmail.com;


Kozo Watanabe (Co-Presenter/Co-Author), Ehime University, Japan, watanabe_kozo@cee.ehime-u.ac.jp;


Thaddeus Carvajal (Co-Presenter/Co-Author), Ehime University, Japan, tads.carvajal@gmail.com ;


Kei Nukazawa (Co-Presenter/Co-Author), University of Miyazaki, Japan, kei.nukazawa@gmail.com ;


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5/20/2019  |   12:15 - 12:30   |  253 AB

ON THE VALUE OF DECAPOD DIVERSITY IN COMPARING WATER QUALITY IN TROPICAL HEADWATER STREAMS All streams share some life-history attributes that are effective in comparing cross-site differences in water quality and food-web structure. However, recent studies demonstrate that some head-water habitats in tropical streams have food webs that are dominated by decapods (freshwater shrimps, crabs, crayfish and aeglas) rather than other types of benthic invertebrates. The life histories of these decapod crustaceans are different from each other. Dispersal, reproduction, and life span affect their function as detritivores, grazers, omnivores, and predators. Together their trophic interactions with other benthic invertebrates, especially aquatic insects, result in changes in the abundance if many other species populations. It is not yet clear how feeding selectivity by many types of decapods affects species that are frequently used to monitor water quality. These decapod populations and their dominance relationships have the potential to alter how current indices of biotic integrity are interpreted. We propose that use the existing data on changes in decapod distributions along with other benthic species will enhance effectiveness of benthic indicators of water quality. We review examples to illustrate that decapod life histories in tropical streams have distinct advantages for determining changes in water quality.

Alan Covich (Primary Presenter/Author), Odum School of Ecology, University of Georgia, a.covich@gmail.com;


Carol Yang (Co-Presenter/Co-Author), University of Georgia, carolyang214@gmail.com ;


Omar Perez-Reyes (Co-Presenter/Co-Author), University of Puerto Rico- Rio Piedras, macrobrachium@gmail.com;


Todd Crowl (Co-Presenter/Co-Author), Florida International University, facrowl@gmail.com;


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