The spatio-temporal dynamics of plant invasions

许多生态学家对植物入侵进行了研究，但很少有人将精力集中在入侵物种扩散的初始阶段和随后的扩散阶段。因此，预测入侵者的蔓延仍然是极其困难的。我的研究计划的目标是研究自然(河流)和人为(道路)结构作为外来植物传播走廊的各自贡献，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。我将把我的研究重点放在魁北克南部的入侵植物上，因为这一地区特别容易受到入侵，它已经被大量采集了植物标本，我已经开发了一个模型来重建魁北克南部的植物传播。我将借助经验数据重建大量外来物种的传播，以描述沿着一条主要入侵途径(黎塞留河)的一般入侵模式。我还将开发一个模型，帮助重建受人类活动，特别是受道路系统影响的景观中植物入侵的动态。我推测，随着公路网的改善，以及在公路网扩建期间或之后，大量以前仅限于自然走廊(河流)的外来物种成为入侵者。为了验证这一假设，我将主要使用标本标本作为信息来源。最后，我将使用古生态工具描述和理解紫色松茸入侵的长期动态。我假设，紫色松散植物入侵包括第一步和第二步，在第一步中，植物形成非常密集的林分，在第二步中，群体衰落并允许本地植物重新建立。将创建的时空模型代表着一项重大而独特的努力，以了解入侵植物沿走廊的传播，特别是在一个受到人类活动和道路系统严重影响的世界中。这些追溯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.