Environmental mediation of the impacts of aquatic invasive species

在世界范围内，在水生生态系统中发现非本地物种的速度越来越快。这些入侵者中的许多只产生轻微的生态影响，而另一些则造成巨大的影响——包括栖息地退化、食物网破坏、渔业崩溃和生物多样性丧失。很难预测哪种入侵会产生不良后果，因为在当地栖息地条件的影响下，入侵者的丰度和影响会在空间和时间上发生很大变化。在这里，我们的目标是研究环境变量在改变入侵者影响中的作用。通过实地和实验室实验，我们将在未来五年内进行三项研究。首先，我们将确定控制入侵掠食性鱼类（圆虾虎鱼）对淡水食物网影响的关键环境因素。其次，我们将研究入侵无脊椎动物沿温度梯度的分布和丰度变化，以了解这些物种在预测的气候变化情景下的生存状况；我们将沿着圣劳伦斯河（St. Lawrence River）一家发电厂人工加热的水域的一系列地点进行这项调查，那里最近发现了亚洲蛤Corbicula fluminea（世界上最具侵略性的双壳类动物之一）的种群。最后，我们将比较来自不同种群的入侵甲壳类动物在其原生和入侵范围内的捕食影响，以检验其一致性。我们还将研究温度和水化学对入侵大湖区的欧亚淡水虾（Hemimysis anomala）捕食影响的影响。劳伦斯河水系。这些研究将为开发生物入侵风险评估模型提供必要的信息。

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.