Admixture and hybridization in North American cattails (Typha spp.)

每年都有数百种--可能是数千种--物种意外或故意地在世界各地迁徙。大多数物种无法在它们被引入的新环境中生存。然而，由于一些不太清楚的原因，一些引进的物种表现得非常好，成为了入侵物种，主导了新的栖息地，导致本土物种灭绝，并花费了数百万美元的根除计划。导致生物入侵的引进不一定涉及特定地理区域的新物种：入侵也可能是引入本地物种的新遗传变种造成的。如果单一物种的种群自然出现在地理上分离的地区，如加拿大沿海省份和不列颠哥伦比亚省，就可能发生这种情况。在这个例子中，加拿大东部和西部的单一物种的种群已经相互隔离了数千年，在此期间，他们进化成具有不同遗传谱系的东部和西部品种，尽管他们仍然被认为是单一物种的成员。如果来自不列颠哥伦比亚省的个体找到了前往沿海省份的途径，它们可能会在新的栖息地变得入侵。 最近引入的遗传谱系可能解释了为什么香蒲(香蒲属、狭叶香蒲属及其杂交品种香蒲属)正成为越来越具侵略性的湿地入侵者。香蒲是湿地栖息地常见的大型植物，虽然它们原产于北美，但最近在加拿大和美国发现了引入欧洲的香蒲。这意味着北美香蒲现在包括原生和引进的遗传谱系，而欧洲的谱系可能是北美香蒲入侵的原因。我们将关注欧洲香蒲在多大程度上主导着加拿大的湿地--无论是它们自己，还是在与北美香蒲杂交后。通过使用香茅作为一个模型系统，我们将产生重要的信息，帮助管理者决定未来通过园艺中心等途径监测“本土”物种的引进有多重要，因为这些‘本土’物种实际上可能代表着具有入侵行为潜力的非本土遗传谱系。了解推动生物入侵的过程是制定旨在最大限度减少未来生物入侵的长期管理计划的必要先导。

Every year hundreds - possibly thousands - of species are either accidentally or intentionally moved around the world. Most species are unable to survive in the new environments to which they are introduced. However, for reasons that are not well understood, a few introduced species fare extraordinarily well and become invasive species that dominate new habitats, drive native species to extinction, and cost millions of dollars in eradication programs. Introductions that lead to biological invasions do not have to involve species that are new to a particular geographical area: invasions can also result from the introduction of new genetic varieties of a native species. This can happen if populations from a single species naturally occur in geographically separated areas, such as the Canadian maritime provinces and British Columbia. In this example, the eastern and western Canadian populations of a single species have been isolated from one another for thousands of years, during which time they evolved into eastern and western varieties with distinct genetic lineages, even though they are still considered members of a single species. If individuals from British Columia find their way to the maritime provinces, they could potentially become invasive in their new habitat. Recently introduced genetic lineages may explain why cattails (Typha latifolia, Typha angustifolia, and their hybrid Typha x glauca) are becoming increasingly aggressive wetland invaders. Cattails are large plants common to wetland habitats, and although they are native to North America, introduced European cattails have recently been identified in Canada and the USA. This means that North American cattails now comprise native and introduced genetic lineages, and the European lineages may be the cause of cattail invasions in North America. We will be looking at the extent to which European cattails - either on their own, or following interbreeding with North American cattails - are dominating Canadian wetlands. By using cattails as a model system, we will generate important information that can help managers to decide how important it will be in the future to monitor introductions of 'native' species through routes such as garden centres, because these 'native' species might actually represent non-native genetic lineages with the potential for invasive behaviour. Understanding the processes that drive biological invasions is a necessary precursor to the development of long-term management plans that aim to minimize future biological invasions.