Spatial and temporal variation in biodiversity: patterns, mechanisms and applications

生态学中最古老的观察之一是生物多样性（例如，不同物种的数量）因地而异。人类活动经常影响生物多样性。因此，确定控制多样性的过程，并表明人类活动如何影响这些过程，将是非常有用的。人们提出了许多假说来解释多样性的模式。其中包括进化和扩散的历史遗产的可能性，多样性的当代上限，以及增加或减少多样性的动态过程。这项工作的目的是从这些假设中得出可检验的预测，检验这些假设，并开发改进的模型，以预测多样性随空间和时间的变化，作为可观察到的栖息地特征的函数。我们这样做的范围从全球到像安大略南部这样的地区。我们还将讨论一些应用问题，如：物种的减少可以预测吗？我们能否确定哪些因素与受《濒危物种法》保护的濒危物种的成功恢复有关？我采用的方法是宏观生态学：也就是说，在覆盖许多不同地区和许多物种群体的大型数据集中寻找模式。在全球尺度的研究中，实验方法很少具有实用性。然而，关于全球现象的假设经常预测应该在自然界中观察到的模式，以及系统应该如何对气候变化等自然扰动作出反应。我用这些预测的大范围模式来检验全球假设。这项工作的主要影响是解决了我们对自然生态系统的理解中一个长期存在的基本问题：为什么有些地方的物种比其他地方多？然而，这项工作也产生了应用影响。如果我们能够确定控制生物多样性的因素，那么我们就可以评估人类活动如何影响这些因素，从而影响生物多样性。最终，我的工作目标是能够预测人类活动将如何影响地球上的多样性分布。

One of the oldest observations in ecology is that biodiversity (e.g., the number of different species) varies enormously from place to place.  Human activities very frequently affect diversity.  Consequently it would be very useful to identify the processes that control diversity, and to show how human activities influence these.          Many hypotheses have been proposed to explain patterns of diversity.  These include the possibility of historical legacies of evolution and dispersal, contemporary caps on diversity, and dynamic processes that increase or decrease diversity.  The purpose of this work is to derive testable predictions from these hypotheses, to test the hypotheses, and to develop improved models that predict the variation of diversity through space and through time, as functions of observable habitat characteristics.  We do this at scales ranging from the entire globe to regions such as southern Ontario.          We will also address applied questions such as: can species decline be predicted?  Can we determine what factors are related to successful recovery of endangered species protected under the Species at Risk Act?        The approach I adopt is macroecological: that is, searching for patterns in large data sets that cover many different areas and many groups of species.  In studies at the global scale, experimental approach is rarely practical.  However, hypotheses about global phenomena often predict patterns that should be observed in nature, as well as how systems should respond to natural perturbations such as climate change.  I use these predicted broad-scale patterns to test global hypotheses.        The main impact of the proposed work is to resolve a very long-standing fundamental problem in our understanding of natural ecosystems: why are there more species in some places than others?  However, this work has applied impacts as well.  If we can identify the factors that control biodiversity, then we can assess how human activities affect those factors, and thus biodiversity.  Ultimately, the goal of my work is to be able to predict how human activities will affect the distribution of diversity on Earth.