The spatio-temporal dynamics of plant invasions

大量的生态学家研究了植物入侵，但很少有人把精力集中在入侵者最初的扩散阶段和随后的传播上。因此，仍然很难预测入侵者的蔓延。我的研究计划的目标是研究自然（河流）和人为（道路）结构作为外来植物的扩散走廊的各自贡献，以及利用河流和道路传播的入侵杂草对植物多样性的长期影响。我将把我的研究工作集中在魁北克南部的入侵植物上，因为这个地区特别容易受到入侵，它已经被大量地取样用于植物标本馆标本，我已经开发了一个模型来重建魁北克南部植物的传播。我将重建，与经验数据的帮助下，传播的一大套外来物种的特点一般入侵模式沿着一个主要的入侵途径（黎塞留河）。我还将开发一个模型，促进重建的动态植物入侵的景观强烈影响人类活动，特别是道路系统。我假设，大量的外来物种，以前仅限于自然走廊（河流）成为入侵者与改善的道路网络，并在公路网的延伸。为了验证这一假设，我将主要使用植物标本作为信息来源。最后，我将描述和理解的长期动态的紫色金钱草入侵使用古生态学工具。我推测，一个紫色的金钱草入侵包括第一步，在该植物形成非常密集的立场，和第二步，在该殖民地下降，并允许重建本地植物。将创建的时空模型代表了理解入侵植物沿着走廊传播的主要和独特的努力，特别是在一个受人类活动和道路系统严重影响的世界中。这些回顾性模型在建模过程中非常重要，因为它们对于更好地理解入侵的动态和测试预测模型至关重要。

A large number of ecologists have studied plant invasions, but very few have concentrated their efforts on the initial stage of dispersal and subsequent spread of invaders. Consequently, it is still extremely difficult to predict the spread of invaders. The objectives of my research program are to study the respective contribution of natural (rivers) and anthropogenic (roads) structures as dispersal corridors for exotic plants, and the long-term impacts on plant diversity of an invasive weed that uses rivers and roads to spread. I will focus my research efforts on the invasive plants of southern Québec because this region is particularly vulnerable to invasions, it has been abundantly sampled for herbarium specimens, and I have already developed a model to reconstruct the spread of plants in southern Québec. I will reconstruct, with the help of empirical data, the spread of a large set of exotic species to characterize general invasion patterns along a major invasion pathway (Richelieu River). I will also develop a model facilitating the reconstruction of the dynamics of plant invasions in a landscape strongly affected by human activities, and particularly by the road system. I hypothesize that a high number of exotic species that were previously restricted to natural corridors (rivers) became invaders with the improvement of the road network, and during or following the extension of the highway network. To test this hypothesis, I will mainly use herbarium specimens as information sources. Finally, I will describe and understand the long-term dynamics of a purple loosestrife invasion using paleoecological tools. I hypothesize that a purple loosestrife invasion consists of a first step, in which the plants form very dense stands, and of a second step, in which colonies decline and allow the re-establishment of native plants. The spatio-temporal models that will be created represent a major and unique effort to understand the spread of invasive plants along corridors, especially in a world heavily impacted by human activities and road systems. These retrospective models are extremely important in the modelling process because they are essential for a better understanding of the dynamics of invasions and for testing predictive models.