SFS Annual Meeting

5/24/2018  |   14:00 - 14:15   |  420 A

A DECADAL ASSESSMENT OF ANTHROPOGENIC IMPACTS TO STREAMS OF NORTHERN MICHIGAN Human actions at the landscape scale are a threat to the ecological integrity of rivers. Some watersheds of Marquette County, Michigan are relatively pristine while others have a long history of logging, mining, and road construction, which have affected the stream habitat, water quality, and biota. These watersheds provide an opportunity to understand long-term anthropogenic stressors. We implemented an annual water-quality monitoring program for 26 sites beginning in 2007 that encompasses a range of anthropogenic influences, which includes data before and during construction and operation of a nearby nickel mine. We evaluated macroinvertebrate community composition, nutrients, water quality parameters, metal concentrations, and habitat conditions at all sites. A habitat assessment provided perspective on changes to the system indicating declining habitat quality over 10 years, while the macroinvertebrate data was highly variable. Site-specific differences in sensitive taxa displayed larger inter-annual variation at sites impacted by construction than isolated sites, potentially due to increased siltation. This study demonstrates that long-term data sets can differentiate between natural variation and anthropogenic changes in stream ecosystems, and can be used to pin-point specific stressors.

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


Ashley Burtner (Co-Presenter/Co-Author), Cooperative Institute for Great Lakes Research, aburtner@umich.edu;


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


Presentation:
This presentation has not yet been uploaded.

5/24/2018  |   14:15 - 14:30   |  420 A

INFLUENCE OF THERMAL REGIME ON THE LIFE HISTORIES OF ROCKY MOUNTAIN AQUATIC INSECTS: A FIELD TEST OF THE THERMAL EQUILIBRIUM HYPOTHESIS Vannote and Sweeney’s Thermal Equilibrium Hypothesis (TEH) predicted that aquatic insect taxa have evolved at a specific range of temperatures where their life history traits such as metabolism, growth rate, and generation time vary with temperature, producing the largest adult body size and fecundity at an 'optimum' temperature. At this optimum, population densities should be maximized; at temperatures outside of this “thermal equilibrium,” taxa are predicted to be less productive. A competing hypothesis, the temperature size rule (TSR), predicts that individuals developing at cold temperatures will grow more slowly, but attain larger body sizes than individuals growing at warmer temperatures. Few studies have investigated the TEH in the field. This study examines how life history traits of four aquatic insect species vary across a natural annual thermal gradient. Results suggest that temperature influences the growth rate, adult body size, fecundity, and generation time of at least some of these species (Hydropsychidae, Ephemerellidae), whereas the TSR was supported across species. In light of global warming trends, these results are integral to understanding how stream temperature influences aquatic insect physiology, which may lead to shifts in species’ geographic ranges and stream communities.

Jennifer McCarty (Primary Presenter/Author), Montana State University, jendmccarty@gmail.com;


Presentation:
This presentation has not yet been uploaded.

5/24/2018  |   14:30 - 14:45   |  420 A

MACROINVERTEBRATE COMMUNITY TRANSITION FOLLOWING CHANGES IN THE THERMAL REGIME BELOW A LARGE DAM IN OREGON Large dams may be tens of meters or more in depth, resulting in strongly stratified reservoirs. Limited water withdrawal points can result in few temperature outflow options. At one such deep reservoir, on the McKenzie River in Oregon, outflows following dam construction resulted in downstream waters which were warmer than pre-dam conditions during the winter and colder during the summer. To minimize temperature related dam impacts a selective water withdrawal ‘temperature control tower,’ a 92 meter wet well with three intake slots and overlapping gates, was constructed and began operations during May 2005. Here we use 6 years of summer macroinvertebrate data, three years before the temperature control tower began operations and three years following (2002-2007), to assess the impacts of downstream temperature control on the instream benthic macroinvertebrate community. We also examine dam impacts by comparing reaches upstream of Cougar Reservoir to reaches downstream. Initial years show a dominance of Chironomids and warm-water tolerant species below Cougar Reservoir, compared to upstream sites. Following the operation of the temperature control tower, the downstream communities exhibited shifts to increasing cold-water and indicator taxa composition.

Christina A. Murphy (Primary Presenter/Author), U.S. Geological Survey, Maine Cooperative Fish and Wildlife Research Unit, Orono, ME, christina.murphy@maine.edu;
things here

Sherri Johnson (Co-Presenter/Co-Author), U.S. Forest Service, Pacific Northwest Research Station, sherrijohnson@fs.fed.us;


William Gerth (Co-Presenter/Co-Author), Oregon State University, william.gerth@oregonstate.edu;


Gregory Taylor (Co-Presenter/Co-Author), US Army Corps of Engineers, gregory.a.taylor@usace.army.mil ;


Presentation:
This presentation has not yet been uploaded.

5/24/2018  |   15:15 - 15:30   |  420 A

INITIAL ASSESSMENT OF RATES OF CERCARIAE INFECTIONS IN HOST SNAIL POPULATIONS Schistosomiasis (swimmer’s itch) is caused by a parasitic trematode that involves snails as the intermediate host. Assessing the potential occurrence of swimmer’s itch infections during the recreational season is linked to the abundance of snails and the percentage of snails infected. We assessed the percentage of snails infected in Higgins Lake, MI which had experienced significant outbreaks of swimmer’s itch in recent years. Snail infection rates ranged from 0% to over 7% during the summer. Infection rates peaked in early June and again in early August which may correspond to the seasonal presence of the terminal host (common mergansers). Rates dropped slightly in late June, a period when the parasites are likely to exit the snail host in search of a terminal host. We suggest that snail infection rates provide a reasonable estimate of the presence of schistosome parasites present in a system and may indicate the risk of swimmer’s itch in a given summer.

Mark Luttenton (Co-Presenter/Co-Author), Annis Water Resources Institute, Grand Valley State University, luttentm@gvsu.edu;


Nathaniel Akey (Primary Presenter/Author), Grand Valley State University, akeyn@mail.gvsu.edu;


Presentation:
This presentation has not yet been uploaded.