Environmental mediation of the impacts of aquatic invasive species

点击翻译按钮获取中文摘要

Non-native species are being discovered in aquatic ecosystems at increasing rates worldwide. Many of these invaders have only minor ecological effects, whereas others cause dramatic impacts - including habitat degradation, food web disruption, fishery collapse, and biodiversity loss. It is very difficult to predict which invasion will have undesirable consequences, because the abundance and impact of an invader can vary greatly across space and time under the influence of local habitat conditions. Here, our goal is to examine the role of environmental variables in modifying the effects of invaders. Using field and laboratory experiments, we will pursue three lines of research over the next five years. First, we will identify key environmental factors that govern the impacts of an invasive predatory fish (the round goby Neogobius melanostomus) on freshwater food webs. Second, we will examine changes in the distribution and abundance of invasive invertebrates along a temperature gradient in order to understand how these species may fare under projected climate change scenarios; we will conduct this investigation along a series of sites in waters artificially heated by a power plant in the St. Lawrence River, where a population of the Asian clam Corbicula fluminea (one of the world's most invasive bivalves) was discovered recently. Finally, we will compare the predation impact of invasive crustaceans from different populations in their native and invaded ranges in order to test their consistency. We will also examine the influence of temperature and water chemistry on the predation impact of a Eurasian freshwater shrimp (Hemimysis anomala) currently invading the Great Lakes-St. Lawrence River system. These studies will yield information essential to the development of risk assessment models for biological invasions.