Poster Details
FRESH INVASIONS: POPULATION GROWTH OF A RECENT INVADER, THE NEW ZEALAND MUD-SNAIL, AND THE EFFECTS ON NATIVE COMMUNITIES IN THE AU SABLE RIVER (MICHIGAN, USA)
The New Zealand mud-snail (NZMS) (Potamopyrgus antipodarum), a world-wide invader, is expanding its range throughout North America with recent invasions in rivers of the Laurentian Great Lakes region. However, given the recency of the invasion, population dynamics and impacts to invaded systems are currently unknown. Here we present results from a world-renowned trout stream, and the effects of NZMS on native benthic-community structure and higher trophic consumers. Benthic invertebrate samples were taken every 4 months over a three-year period, and fish diet analysis was conducted annually. We found that NZMS is increasing in abundance, with populations exhibiting linear growth at a mean rate of 25,185 individuals/yr., and some samples showing densities exceeding 100,000 individuals/m2. Mean densities showed a 500-fold increase over the three-year time frame. Dietary analysis of brown trout (Salmo trutta) revealed increased consumption of NZMS, over 2 years, with the mean proportion (+/- SD) of mud-snails in diets rising from 8.99% +/- 13.03 to 28.72% +/-32.91 (P = 0.02). These and forthcoming results show that this new invader may affect native community structure and potentially alter the trophic energy flow of the Au Sable River.
Jeremy Geist (Primary Presenter/Author), Dept. of Biological Sciences, Oakland University, jageist@oakland.edu;
Mark Luttenton (Co-Presenter/Co-Author), Annis Water Resources Institute, Grand Valley State University, luttentm@gvsu.edu;
Scott Tiegs (Co-Presenter/Co-Author), Oakland University, tiegs@oakland.edu;