Monday, May 18, 2015
15:30 - 17:00

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15:30 - 15:45: / 101A ASSESSING THE POTENTIAL ROLE OF ROUND GOBY AS A CONDUIT FOR AVIAN BOTULISM IN LAKE MICHIGAN

5/18/2015  |   15:30 - 15:45   |  101A

ASSESSING THE POTENTIAL ROLE OF ROUND GOBY AS A CONDUIT FOR AVIAN BOTULISM IN LAKE MICHIGAN Invasive species from the Ponto-Caspian region have been implicated in restructuring of the Lake Michigan food web over the past several decades. These changes have been coincident with a major increase in the number of bird deaths associated with avian botulism. Round goby, one of the most prolific invaders, now constitute a major prey resource for piscivorous birds. We investigated the trophic role of gobies in the emerging food web as well as seasonal behavior patterns and their relationship to botulism outbreak events in the Sleeping Bear Dunes National Lakeshore region of Lake Michigan. Stable C and N isotopes and gut content analysis were used to assess trophic role, and time lapse imagery was used to capture temporal abundance patterns of goby during the study period, 2010-2014. Our results suggest a potential trophic pathway for the botulinum toxin to pass from hypoxia-tolerant benthic invertebrates, such as chironomids, to gobies which are then susceptible to avian predation. Temporal increases in goby abundance over hypoxic sediments appear to be synchronized with annual bird migrations through the study region.

Benjamin Turschak (Primary Presenter/Author), University of Wisconsin-Milwaukee, turschak@uwm.edu;


Harvey Bootsma (Co-Presenter/Co-Author), University of Wisconsin-Milwaukee, hbootsma@uwm.edu;


Brenda Moraska Lafrancois (Co-Presenter/Co-Author), National Park Service , Brenda_Moraska_Lafrancois@nps.gov;


15:45 - 16:00: / 101A LAND-USE PROXIES FOR AQUATIC SPECIES INVASIONS IN THE LAURENTIAN GREAT LAKES

5/18/2015  |   15:45 - 16:00   |  101A

LAND-USE PROXIES FOR AQUATIC SPECIES INVASIONS IN THE LAURENTIAN GREAT LAKES Aquatic invasive species adversely impact ecosystems, human health, and the economy of the Laurentian Great Lakes region. Targeted preventative and eradication efforts in response to early detection of invasive species can be both cost advantageous and effective. But where should we focus limited time and resources searching for the next new invader. I investigated land-use metrics of three prominent anthropogenic introduction pathways (commercial boat traffic, recreational boat traffic, and live release from urban centers), to explain the apparent spatio-temporal patterns of historic aquatic invasions. Of those evaluated, city population size was the best indicator of aquatic invasive species presence and richness, even for species introduced through ballast water discharge. Near shore waters adjacent to large cities had a much higher probability of species presence than medium or small cities. Additionally, commercial boat traffic was a significant indicator of where initial introductions occurred, but was inconsistent at predicting spread post-introduction. Developing and evaluating indicators of historic aquatic invasions will guide future early detection efforts to slow and prevent new introductions.

Elon O'Malia (Primary Presenter/Author), University of Minnesota Duluth & US EPA, omali001@umn.edu;


Joel Hoffman (Co-Presenter/Co-Author), U.S. Environmental Protection Agency, hoffman.joel@epa.gov;


16:00 - 16:15: / 101A ASSESSING THE VALUE OF OUTREACH TO BOATERS AS A TOOL FOR REDUCING INTRODUCTION AND SPREAD OF INVASIVE AQUATIC SPECIES

5/18/2015  |   16:00 - 16:15   |  101A

ASSESSING THE VALUE OF OUTREACH TO BOATERS AS A TOOL FOR REDUCING INTRODUCTION AND SPREAD OF INVASIVE AQUATIC SPECIES Freshwater invasive species continue to arrive, become established, and spread in the US. Recreational boating is a strong vector for these species and extensive resources are devoted to outreach programs encouraging boaters to modify their behaviors. Little work has been conducted, however, to determine whether this outreach is effective in reducing the spread and impacts from invasive species. We conducted a survey (n=556 respondents) in Illinois to determine the relationship between the practices of boaters and their exposure to outreach messages. We found that although most boaters have received outreach messages and are familiar with the problems of invasive species, over 20% do not actively remove organisms from their boats. Almost all lakes remain exposed to this high-risk group; of 35 lakes examined we found that all were visited during a 12 month period by boaters who do not make efforts to clean their boats. Although outreach efforts appear to be successful at reaching the majority of boaters and affecting their behaviors, reducing invasion rates may require new approaches that focus on boaters that have not adopted these behaviors.

Reuben Keller (Primary Presenter/Author), Loyola University Chicago, rkeller1@luc.edu;


Ellen Cole (Co-Presenter/Co-Author), Loyola University Chicago, ecole3@luc.edu;


Kelly Garbach (Co-Presenter/Co-Author), Loyola University Chicago, kgarbach@luc.edu;


16:15 - 16:30: / 101A POPULATION COLLAPSE OF INVASIVE RUSTY CRAYFISH IN NORTHWOODS LAKES OF WISCONSIN, USA

5/18/2015  |   16:15 - 16:30   |  101A

POPULATION COLLAPSE OF INVASIVE RUSTY CRAYFISH IN NORTHWOODS LAKES OF WISCONSIN, USA The abundance and impacts of nonindigenous species often change through the course of invasion as they alter food webs and ecosystems, but most research occurs at temporal and spatial scales that are too short and small to capture these important dynamics. For example, the prevalence of population "busts" in which established invaders decline or even disappear over time is difficult to evaluate without long-term monitoring of invasions. We use nearly 40 years of data (1975-2014) on the abundance of invasive rusty crayfish in 17 Vilas County, Wisconsin, USA lakes to evaluate the long-term fate of these populations, including whether or not some lakes have experienced busts of previously abundant rusty crayfish. Although rusty crayfish populations have remained high in some lakes, nine lakes (53%) have experienced significant, sustained declines of rusty crayfish from earlier peaks. We discuss potential factors contributing to population collapse of rusty crayfish, including prevalence of crayfish-supporting habitat (e.g., cobble substrate), recent climatic patterns (e.g., drought), and crayfish-parasite dynamics.

Eric Larson (Primary Presenter/Author), Shedd Aquarium, lars9570@uw.edu;


Timothy Kreps (Co-Presenter/Co-Author), Bridgewater College, tkreps@bridgewater.edu;


David Lodge (Co-Presenter/Co-Author), University of Notre Dame, lodge.1@nd.edu;


16:30 - 16:45: / 101A SPECIES INTRODUCTION ALTERS NUTRIENT RECYCLING PATTERNS OF INTRODUCED GUPPY FISH AND RESIDENT KILLIFISH SPECIES IN TRINIDAD

5/18/2015  |   16:30 - 16:45   |  101A

SPECIES INTRODUCTION ALTERS NUTRIENT RECYCLING PATTERNS OF INTRODUCED GUPPY FISH AND RESIDENT KILLIFISH SPECIES IN TRINIDAD Species introduction is a significant global problem; yet little is known about the long-term effects of introductions. Guppies (Poecilia reticulata) from Trinidad are used as a model to study the evolutionary and ecological effects of species introductions. We identified sites where guppies were introduced to previously guppy-free stream locations 4, 6, 24, and over 50 years ago. These streams are co-inhabited by native killifish (Anablepsoides hartii) and remained guppy free upstream of these introduction sites. We characterized how fish-mediated nutrient recycling changed over time since invasion, as guppies adapted to their new habitats and caused killifish populations to decline. We measured fish nitrogen excretion rates along the guppy introduction continuum and compared them to upstream guppy-free sites. Guppy excretion rates were highest in recent introductions (avg. 31 ug N/hr/g fish) and steadily declined with time since introduction (to avg. 12 ug N/hr/g fish). Excretion rates of killifish decreased shortly after guppy introductions, but returned to pre-introduction rates within 50 years. We hypothesized that adaptation and competition for food resources between guppies and killifish facilitated these patterns.

Therese C. Frauendorf (Primary Presenter/Author), University of Victoria, tfrauend@uvic.ca;


Piatã S. Marques (Co-Presenter/Co-Author), University of Victoria, piata@uvic.ca;


Misha Warbanski (Co-Presenter/Co-Author), University of Victoria, misha.warbanski@gmail.com;


Dawn Phillip (Co-Presenter/Co-Author), University of West Indies, Dawn.Phillip@sta.uwi.edu;


Rana El-Sabaawi (Co-Presenter/Co-Author), University of Victoria, rana@uvic.ca;


16:45 - 17:00: / 101A ABIOTIC EFFECTS ON SPATIAL DISTRIBUTION AND ABUNDANCE OF TWO HIGHLY HIGHLY INVASIVE SPECIES IN A NOVEL LAKE ECOSYSTEM

5/18/2015  |   16:45 - 17:00   |  101A

ABIOTIC EFFECTS ON SPATIAL DISTRIBUTION AND ABUNDANCE OF TWO HIGHLY HIGHLY INVASIVE SPECIES IN A NOVEL LAKE ECOSYSTEM The prevalence, spread and impact of invasive species are magnified and unpredictable in novel ecosystems. In Lake Seminole, a reservoir at the confluence of the Chattahoochee and Flint Rivers in southwestern Georgia, the distribution of two highly invasive species, Hydrilla verticillata and Pomacea maculata, are anticipated to alter biogeochemical processes. Mapping of native and non-native submerged aquatic vegetation has documented responses to drought and subsequent hydrologic recovery. H. verticillata is now a dominant macrophyte species in terms of lake surface cover during the growing season in drought years. Its seasonal growth is likely delayed by turbidity associated with spring runoff. P. maculata, more recently introduced, has shown range expansion but may be limited by physiochemical properties, including temperature and calcium. Pomacea expansion throughout the lake may occur as a result of warming water temperatures. Macrophyte dominance may shift as a result of P. maculata grazing, altering the trophic state, and function, of the lake.

Nicholas Marzolf (Primary Presenter/Author), J.W. Jones Ecological Research Center, nmarzolf@jonesctr.org;


Stephen Shivers (Co-Presenter/Co-Author), US EPA Office of Research and Development ORISE Fellow, Shivers.stephen@epa.gov;


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


Stephen Golladay (Co-Presenter/Co-Author), Georgia Water Planning and Policy Center at ASU, steve.golladay@jonesctr.org;