5/24/2016  |   10:30 - 10:45   |  311-312

JUST A MATTER OF TIME? MODELING THE RAPID SPREAD OF INVASIVE CRAYFISH IN THE COLUMBIA RIVER Mounting ecological impacts of aquatic invasive species emphasize the need for integrated approaches to modeling population spread through space and time. Such models provide managers with meaningful recommendations for how to guide prevention by identifying and prioritizing areas most at risk of invasion. In 2005, the unexpected occurred when rusty crayfish (Orconectes rusticus), native to mid-central U.S., was discovered in a major tributary of the Columbia River, marking its first recorded occurrence west of the North American continental divide. Over the past decade, it has spread downstream at >10 km/year, and there is mounting concerns regarding its impacts on native species, including Pacific salmon. Here, we modeled the spread of rusty crayfish in the John Day River (Oregon) using a spatially explicit individual-based model. This framework merges data on species life-history, environmental conditions, and competition and predation, to model population structure in both time and space. Model simulations allow for reconstructing past patterns of crayfish spread and forecasting future distributions. Using this mechanistic model, we explore management strategies aimed at slowing the spread of rusty crayfish in the future.

Mathis L. Messager (Primary Presenter/Author), Department of Geography, McGill University, Canada | RiverLy Research Unit, INRAE, France, mathis.messager@mail.mcgill.ca;


Julian Olden ( Co-Presenter/Co-Author), University of Washington, olden@uw.edu;


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5/24/2016  |   10:45 - 11:00   |  311-312

IMPACT OF AN INVASIVE CRAYFISH, PROCAMBARUS CLARKII, ON BENTHIC COMMUNITY STRUCTURE IN SOUTHERN CALIFORNIA DEPRESSIONAL WETLANDS Impacts of invasive species are often detrimental to an invaded ecosystem and are of particular interest to environmental managers aiming to preserve or restore natural habitat. The red swamp crayfish, Procambarus clarkii, has become an important ecological pest outside of its native range. The aim of this study is to conduct in situ mesocosm experiments to determine the effects of crayfish presence on algal biomass and benthic community structure in two lentic field sites. Crayfish density was manipulated to create three treatment levels: 0 crayfish/m2 exclusion cages, 2 crayfish/m2 inclusion cages, and ambient crayfish density cages to control for cage effects. Algal growth was collected on settling plates and benthic invertebrate samples were collected using kick nets following the two month experimental period. We expect crayfish presence to decrease the relative abundance of gastropod taxa. Due to this predatory pressure, we expect algal biomass to increase in the presence of crayfish and for non-gastropod herbivore taxa to increase in relative abundance, replacing the removed gastropod taxa.

Matthew Schliebe (Primary Presenter/Author), California State University Long Beach, mcschliebe@gmail.com;


Dessie Underwood ( Co-Presenter/Co-Author), California State University Long Beach, dessie.underwood@csulb.edu;


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5/24/2016  |   11:00 - 11:15   |  311-312

PARASITE FAUNA OF INVASIVE FRESHWATER FISHES WITH INSIGHTS INTO DRIVING FACTORS OF PARASITE OCCURRENCE. Parasites have a wide range of impacts on their community. Current data on the parasites found in North American freshwater fish has revealed considerable gaps in the knowledge of the parasite species composition, host specificity, evolution, and host-parasite relationships. To explore this we used a two-year field survey in California freshwater ponds to identify invasive fish parasites and to investigate the driving factors that determine a fish parasite’s community and infection load. Of the 604 dissected invasive fish species over half were infected with at least one parasite resulting in a total of eleven different species of parasites. Posthodiplostomum minimum was the most prevalent and had the highest average parasite load. Parasite richness also varied among the five dissected fish hosts and the total aquatic richness was a positive predictor of parasite richness. Among wetland host species studied host identity was more important than environmental variables. Given rises in the incidence of infectious diseases caused by invasive species introductions, understanding the ecological factors that control parasite burden within hosts and pathogenicity among hosts is of prime importance for biodiversity conservation.

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


Dana Calhoun (Primary Presenter/Author), University of Colorado: Boulder, dana.calhoun@colorado.edu;


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5/24/2016  |   11:15 - 11:30   |  311-312

INDICATORS OF SITE CONDITION CORRELATE WITH ROUND GOBY DISTRIBUTION IN MICHIGAN RIVERS Disturbance can leave ecosystems in vulnerable states, increasing opportunity for nonnative species to colonize (invasibility). To test this concept, we conducted surveys on fish and macroinvertebrate communities and water quality in several rivers in Michigan exhibiting a range in overall condition to determine the factors associated with invasibility of round goby (Neogobius melanostomus). Factors affecting site condition were addressed at multiple scales, first with multiple linear regression of land cover at the watershed scale, followed by an assessment of macroinvertebrate data provided by watershed monitoring groups to identify fine-scale geographic patterns. Land cover type was not significantly correlated with round goby density. Chi-square analysis confirmed that sites with lower designations of site condition, determined by watershed monitoring data, had higher than expected abundances of round goby (?2=18.79; p<0.001). Finally, non-metric multidimensional scaling of fish communities from our own survey showed divergent compositions between low and high quality sites, potentially indicating antagonistic interactions between native fishes and round goby. Our ongoing research is aimed at disentangling causal factors constraining and promoting goby invasion, and determining potential impact on newly invaded areas.

Corey Krabbenhoft ( Co-Presenter/Co-Author), University of Minnesota, krabb012@umn.edu;


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


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5/24/2016  |   11:30 - 11:45   |  311-312

MODELING THE EFFECTS OF CONTROL EFFORTS ON A POPULATION OF COMMON CARP (CYPRINUS CARPIO) IN A SHALLOW EUTROPHIC DESERT LAKE The introduction of Common Carp (Cyprinus carpio; hereafter “carp”) into North American waterways has led to widespread destruction of aquatic ecosystems. This destruction can be found in Malheur Lake, located in Southeastern Oregon. Invasion of carp is believed to be responsible for the loss of aquatic vegetation as well as declines in waterfowl productivity. Efforts to remove carp and restore the aquatic ecosystem have included rotenone treatments, which led to an immediate decline in the carp population, inevitably followed by a rapid rebound in subsequent years. Accordingly, MNWR has sought to identify new alternatives to control carp and better understand their population dynamics. We aim to develop a novel carp population dynamic model, which will then be used to explore the efficacy of alternative control measures (commercial fishing, electroshocking eggs, and avian predation). Collectively, the results of these model simulations represent a realistic assessment of multiple factors that will influence the success of carp control in Malheur Lake, and the ability to use carp control as a means of restoring the aquatic health in the system.

James Pearson (Primary Presenter/Author), Oregon State University, James.Pearson@oregonstate.edu;


Jason Dunham ( Co-Presenter/Co-Author), U. S. Geological Survey, jdunham@usgs.gov;


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5/24/2016  |   11:45 - 12:00   |  311-312

INVASIONS THREATEN THE ANTIQUITY OF CHINA’S FRESHWATER FISH FAUNA By dissolving natural physical barriers to movement, human-mediated species introductions have dramatically reshuffled the present-day biogeography of freshwater fishes. This is particularly true in China where species invasions, coupled with habitat modification and overexploitation, greatly threatens the future of native fish faunas. In this study, we quantified patterns and consequences of widespread fish invasions across China and predict the future changes in similarity of China’s freshwater ichthyofauna. The introduction of 147 nonnative fishes has increased faunal similarity among major watersheds by an average of 7.0%; over 93% of the watersheds showed evidence for homogenization. The homogenization was only caused by few widely distributed species. Domestic translocated species contributing the most to this change and most of high-contribution species are important cultured species. In the future, China’s fish fauna will keep homogenized even considering the establishment of new invasive species, with translocated species still having higher contribution. Together, our study highlights the importance of understanding the role of invasive species in defining patterns of present-day biogeography and preserving the endemism of China’s fish diversity.

Chunlong Liu (Primary Presenter/Author), University of Washington & Chinese Academy of Sciences, liuchunlong113@gmail.com;


Julian Olden ( Co-Presenter/Co-Author), University of Washington, olden@uw.edu;


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