The spatiotemporal dynamics of plant invasions

在过去的20年里，我的研究团队已经表明，寒温带地区的外来植物耐寒，能够利用公路网等资源(栖息地)，它们的种群将迅速扩大，并入侵新的地区。尽管如此，它们对生物多样性的影响是依赖于背景的，它们对其他动植物种群动态的影响程度仍有待验证。我的研究计划的长期目标是了解为什么某些外来植物物种在建立大种群方面比其他物种更成功。在接下来的5年里，我有4个短期目标。(1)通过对历史园林的研究，探讨观赏植物归化的影响因素。通过将种植在花园中的物种名单与在其附近归化的物种进行比较，我希望能更好地了解与归化相关的过程。我假设植物的抗逆性是一个重要的解释因素，但繁殖压力对归化成功也同样重要。(2)我还想从历史(以标本为基础)的角度探讨植物入侵(敌人释放)的主要假设之一。我假设外来物种从一开始就接触到引入范围内已经存在的食草动物/病原体，但随着植物种群的扩大(更大的食物来源或寄主丰度，对新食物来源的长期适应)，攻击会增加。我相信长期的草食/病原体趋势(对植物的影响)可以通过标本标本检测出来。(3)我想确定道路是否不仅是走廊，而且是杂草的入侵中心，因为入侵者将其人口从交通走廊扩展到邻近土地的程度仍有待量化。尽管道路网络可能构建了入侵者在一个地区的空间分布，但我假设栖息地特征更好地解释了道路附近入侵者的种群大小。(4)研究两种植物入侵对河岸生态系统生态系统功能(侵蚀防护)的影响，以准确评价这两种植物对河岸侵蚀的影响。我假设，与普遍的看法相反，RJ对侵蚀的影响很小，因为它有广泛的根状根系统。另一方面，我假设IG对侵蚀的影响是很大的，特别是在春季冰川运动的地区。这种影响将是多年生植物被这种一年生植物取代的结果，导致银行在晚秋完全没有植被。这项研究计划将对了解加拿大和其他寒温带地区的生物入侵和植物生物地理学做出重大贡献。

My research team has shown, over the last 20 years, that exotic plants of cold-temperate regions that are cold hardy and able to exploit a resource (habitat) like the road network will rapidly expand their populations and invade new regions. Nonetheless, their effects on biodiversity are context-dependent, and the extent of their impacts on the population dynamics of other plants or animals remains to be verified. The long-term objective of my research program is to understand why certain exotic plant species are more successful than others in establishing large populations. For the next 5 years, I have 4 short-term goals. (1) I propose to investigate the factors responsible for ornamental plant naturalization by studying historical gardens. By comparing the list of species planted in the gardens to those that naturalized in their vicinities, I expect to better understand processes associated with naturalization. I hypothesize that plant hardiness is an important explanatory factor, but that propagule pressure is equally important to naturalization success. (2) I also want to explore one of the main hypotheses of plant invasions (enemy release) from a historical (herbarium-based) perspective. I hypothesize that exotic species are exposed from the outset to herbivores/pathogens already present in the introduced range, but that the attacks increase with plant population expansion (larger food source or host abundance, long-term adaptation to a new food source). I believe that long-term herbivory/pathogen trends (impacts on plants) can be detected with herbarium specimens. (3) I want to determine whether roads act not only as corridors, but also as invasion foci for weeds, because the extent to which invaders expand their populations from transportation corridors to adjoining lands remains to be quantified. Although a road network probably structures the spatial distribution of invaders over a region, I hypothesize that habitat characteristics better explain population size of invaders near roads. (4) Finally, I propose to investigate the effects of two plant invaders (Reynoutria japonica RJ and Impatiens glandulifera IG) on ecosystem functions (erosion protection) in riparian ecosystems, to precisely evaluate whether these plants have an impact on river bank erosion. I hypothesize, contrary to general belief, that the effect of RJ on erosion is minor because of its extensive rhizomatous root system. On the other hand, I hypothesize that the impact of IG on erosion is major, especially in regions with ice movement in spring. This impact would be a consequence of the replacement of perennials by this annual, leaving banks totally devoid of vegetation in late fall. This research program will significantly contribute to the understanding of biological invasions and plant biogeography in Canada and other cold-temperate areas.