The New Zealand Mud Snail (Potamopyrgus Antipodarum) Ecology And Management Of A Global Invader

The New Zealand mud snail (Potamopyrgus antipodarum; NZMS) is among the most globally widespread aquatic invaders, colonizing at least 40 countries across 6 continents. NZMS have recently colonized rivers of the Laurentian Great Lakes region. where little is known about their impacts on the native communities of the ecosystems they invade. In chapter one, I present the results of a systematic review of 245 articles, and outline NZMS impacts, distribution, population dynamics, vectors of spread, and management. The invasion success of NZMS stems from their opportunistic traits allowing them to tolerate broad ranges of environmental conditions. However, optimal conditions for successful establishment are evident. NZMS can become exceptionally abundant and impact multiple facets of aquatic ecosystems, though populations can fluctuate seasonally and over longer time scales, likely due to environmental constraints. In chapter two, I tested the efficacy of three different chemical reagents for NZMS decontamination on recreational fishing gear and combined these results with results of a self-administered public survey gauging the level of willingness individuals have to participate in a given NZMS decontamination technique. The greatest mortality of NZMS was caused by Formula 409, and participants of the survey revealed Formula 409 to be the chemical they'd be most willing to use. Chapter three outlines an investigation of the effects of NZMS on the diets and condition of fish in a recently invaded stream, the Au Sable River (Michigan, USA). Trout consumed NZMS throughout the duration of the study, while sculpin minimally consumed NZMS. Of the 83 trout collected, 60% contained NZMS in their stomachs. Age 2 trout that consumed NZMS exhibited reduced condition relative to those that contained fewer NZMS. Lastly, chapter four consists of a study to characterize NZMS population dynamics and their effects on native benthic invertebrates in the Au Sable River. NZMS populations exhibited pronounced seasonality with peak densities typically occurring during the Summer and Autumn of each year. NZMS numerically dominated the benthic community and were associated with differences in the overall benthic community composition. The results of these studies highlight how NZMS can affect native communities and higher consumers in rivers of the Great Lakes region and contribute to a more robust understanding of the global NZMS invasion, such that undesired impacts can be minimized or averted.