Biological invasions and the spatial ecology of genes

入侵物种是指被引入其自然范围以外的地区，随后扩散并主导原生栖息地的植物和动物。因为它们是生物多样性的主要威胁，而且还会大大降低农业生产力，每年都要花费数十亿美元来对抗入侵者。然而，我们不能成功地击退入侵者，除非我们更好地理解是什么让一些引入的物种具有侵略性，而另一些物种保持稳定。带着这个目标，我把注意力集中在芦苇（芦苇南）上，这是一个以在包括北美和欧洲在内的世界各地的淡水地点形成的芦苇床而闻名的物种。在这两个大陆，本土芦苇的数量已经稳定了数千年，但在一个多世纪前，当一种欧洲普通芦苇品种被引入北美时，这一切都发生了变化。这种菌株现在正在入侵北美，那里的种群正在迅速扩散，并占领了河口、湖泊、池塘、溪流和其他栖息地，这些栖息地以前是各种物种的家园。入侵芦苇现在是一个问题，它们已被确定为加拿大自然栖息地最具破坏性的植物之一。

Invasive species are plants and animals that are introduced to regions outside their natural range, and subsequently spread out and dominate native habitats. Because they are a major threat to biodiversity, and can also greatly reduce agricultural productivity, billions of dollars are spent each year fighting invaders. However, we cannot successfully repel invaders until we have a better understanding of just what makes some introduced species invasive while others remain stable. With this goal in mind, I am concentrating on the common reed (Phragmites australis), a species that is well known for the reed beds that it forms in freshwater sites round the world including North America and Europe. In both continents, native reed populations have been stable for thousands of years, but this all changed in North America more than a century ago when a European strain of the common reed was introduced. This strain is now invasive in North America, where populations are spreading rapidly and taking over estuaries, lakes, ponds, streams, and other habitats that were previously home to a wide range of species. Invasive reeds are now such a problem that they have been identified as one of the most destructive plants in Canadian natural habitats.