The spatiotemporal dynamics of plant invasions

我的研究团队在过去的20年里已经证明，寒冷的温带地区的外来植物，寒冷的哈代，能够利用资源（栖息地），如道路网络，将迅速扩大其人口和入侵新的地区。然而，它们对生物多样性的影响取决于具体情况，它们对其他动植物种群动态的影响程度仍有待核实。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。在接下来的五年里，我有四个短期目标。(1)我建议通过研究历史园林来探讨观赏植物归化的因素。通过比较花园中种植的物种列表与那些在其附近归化的物种，我希望更好地理解与归化相关的过程。我假设，植物抗寒性是一个重要的解释因素，但繁殖体压力是同样重要的归化成功。(2)我还想从历史（基于植物标本馆）的角度探讨植物入侵的主要假设之一（敌人释放）。我假设外来物种从一开始就暴露在已经存在于引进范围内的食草动物/病原体中，但随着植物种群的扩张（更大的食物来源或宿主丰度，对新食物来源的长期适应），攻击增加。我相信，长期的食草动物/病原体的趋势（对植物的影响）可以检测与植物标本。(3)我想确定道路是否不仅是走廊，而且还是杂草的入侵中心，因为入侵者将其种群从交通走廊扩展到邻近土地的程度仍然有待量化。虽然道路网络可能结构的入侵者在一个区域的空间分布，我假设栖息地的特点更好地解释人口规模的入侵者附近的道路。(4)最后，我建议调查两种植物入侵者（日本野螟RJ和腺凤仙IG）对河岸生态系统的生态系统功能（侵蚀防护）的影响，以准确地评估这些植物是否对河岸侵蚀的影响。我假设，与一般的看法相反，RJ对侵蚀的影响是轻微的，因为其广泛的根茎根系。另一方面，我假设IG对侵蚀的影响是主要的，特别是在春季有冰运动的地区。这种影响将是多年生植物被一年生植物取代的结果，使银行在深秋完全没有植被。这项研究计划将大大有助于在加拿大和其他冷温带地区的生物入侵和植物地理学的理解。

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.