Evolutionary and ecological responses of a native plant community to species introductions

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。据预测，全球气候变化将促进潜在有害入侵物种向北迁徙；加拿大预计将成为此类物种的净接受国。生物防治计划的目标是利用天敌进行入侵物种管理，由于它们不依赖于潜在有害化学品的应用，因此很有吸引力。然而，将一种新物种引入生态系统并非没有风险。最紧迫的是，我们目前预测多物种相互作用的进化和生态结果的能力受到阻碍，因为在这一领域普遍缺乏理论和实证工作。例如，我们目前预测本地物种对外来入侵物种的进化或生态反应的能力非常有限。此外，几乎没有数据或模型可以帮助我们预测这些反应可能会如何因随后引入另一种新物种而改变，例如生物控制剂。入侵植物紫松毛虫及其生防剂草食性甲虫在加拿大和美国的引进和迁徙为探索这些问题提供了一个引人注目的系统。所获得的知识将有助于发现科学的一个关键领域，并有助于制定关于管理入侵物种的政策。

Invasive species have the potential to do major ecological harm, and their management costs governments billions of dollars annually. 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. Biological control programs, the goal of which is take advantage of natural enemies for invasive species management, are appealing because they do not rely on the application of potentially harmful chemicals. However, the introduction of a new species to an ecosystem is not without risks. Most pressingly, we are currently hampered in our ability to predict the evolutionary and ecological outcome of multi-species interactions because of a general lack of theoretical and empirical work in this area. For example, we currently have very limited ability to make predictions about the evolutionary or ecological response of native species to the introduction of an invasive species. Furthermore, almost no data or models exist to help us predict how such responses might be altered by the subsequent introduction of another novel species, such as a biological control agent. The introduction and migration of the invasive plant purple loosestrife and its biocontrol agent, a herbivorous beetle, in Canada and the United States, offer a compelling system in which to explore these questions. The knowledge gained will both contribute to a key area of discovery science and the development of policy regarding the management of invasive species.