Using species introductions to gain insight about key biological processes

入侵物种有可能造成重大的生态危害，它们的管理每年要花费政府数十亿美元。此外，全球气候变化将促进潜在有害入侵物种的北迁；预计加拿大将是这类物种的净接受国。然而，由于在这一领域普遍缺乏理论和实证工作，我们目前在预测本地和农业生态系统对物种入侵的进化和生态反应方面的能力受到阻碍。我们对物种的引入已经有了一定的了解，并且可以控制释放的时间和地点，这为我们提供了一个强大的系统，可以用来测试物种组成和相互作用在群落进化和生态过程中的作用。生物控制计划的目标是利用天敌来管理入侵物种，这是一个很有吸引力的工具，因为它们可以用来代替潜在的有害化学物质。然而，将新物种引入现有生态系统并非没有风险。在加拿大和美国，入侵植物紫松花及其生物防治剂（一种食草甲虫）的引入和迁移，为探索当地群落对物种入侵的生态和进化反应提供了一个有吸引力的系统。在这里，我概述了一个研究计划，该计划将检查适应性框架是否允许我们提高预测物种引入对本地植物群落的长期和短期影响的能力。所获得的知识将有助于发现科学的一个关键领域，并有助于改进入侵物种管理政策。

Invasive species have the potential to do major ecological harm, and their management costs governments billions of dollars annually. Moreover, global climate change is predicted to promote the northward migration of potentially harmful invasive species; Canada is expected to be a net recipient of such species. And yet, we are currently hampered in our ability to predict the evolutionary and ecological response of native and agricultural ecosystems to species invasions because of a general lack of theoretical and empirical work in this area. Species introductions for which we have knowledge and control over the timing and location of release present a powerful system in which to test questions about the role of the species composition and interactions in a community on its evolutionary and ecological processes. Biological control programs, the goal of which is take advantage of natural enemies for invasive species management, are an appealing tool because they may be used in the place of potentially harmful chemicals. However, the introduction of a new species into an existing ecosystem is not without risks. The introduction and migration of the invasive plant species purple loosestrife and its biocontrol agent, a herbivorous beetle, in Canada and the United States, offers a compelling system in which to explore the questions surrounding the ecological and evolutionary response of native communities to species invasions. Here I outline a research program that will examine whether an adaptive framework allows us to improve our ability to make predictions about the long and short term impacts of species introductions on native plant communities. The knowledge gained will both contribute to a key area of discovery science and to the improvement of policy on invasive species management.