From plant traits to plant communities

这项建议涉及研究(I)不同植物特性在物种之间进行比较时如何相互关联，(Ii)不同植物特性的值如何决定它们在给定环境中如何生存、生长和繁殖，(Iii)不同环境将如何为不同的特性值进行选择，以及(Iv)这一过程如何确定植物物种组装成生态群落。不同的植物物种和不同类型的植物是不同生境的典型。植物生态学的一个重要但尚未达到的目标是预测哪些物种将在不同的地点和环境中占据主导地位，哪些物种将处于从属地位，哪些物种将缺席(群落“集合”)。我已经开发了一个数学模型来预测这种现象，并理解它是如何在不同环境中由于特征选择而产生的。这个统计模型(“CATS”)将植物功能性状、环境变量和区域种库联系起来，以产生相对丰度的定量预测。在接下来的5年里，我的团队将使用魁北克南部落叶树林的落叶植物群落来提炼猫科动物，这些群落以岛屿的形式存在于农业“海洋”中，在大小、隔离和年龄方面存在差异。在这个系统中，群落聚集的三个主要力量(扩散限制、基于特征的选择和人口随机性)应该特别强大。我们还将测试一个假说，该假说旨在解释众所周知的和非常普遍的叶子性状之间协变模式的因果起源，这一假说将这种模式解释为维管植物如何构建叶片的“设计限制”的结果。最后，我的学生和我将改进和测试一种新的方法来量化一种重要的环境选择因素(土壤肥力)，它是植物生态学中的基本环境选择因素。

This proposal concerns research into (i) how different plant traits are related to each other when comparing between species, (ii) how different values of plant traits  determine how well they can survive, grow and reproduce in a given environment, (iii) how different environments will select for different trait values and (iv) how this process determines the assembly of plant species into ecological communities.  Different plant species, and different types of plants, are typical of different habitats. An important, and unattained, goal of plant ecology is to predict which species will be dominant, which will be subordinate, and which will be absent, in different sites and environments (community "assembly").  I have developed a mathematical model designed to predict this phenomenon and to understand how it arises as a consequence of trait selection in different environments.  This statistical model ("CATS") links plant functional traits, environmental variables, and regional species pools to produce quantitative predictions of relative abundance.  In the next 5 years my team will refine CATS using the understory plant communities of deciduous woods in southern Quebec, which exist as islands in an agricultural "sea" and that differ in terms of size, isolation and age.  In this system the three main forces of community assembly (dispersal limitation, trait-based selection, and demographic stochasticity) should be especially strong.  We will also test an hypothesis which purports to explain the causal origin of a well-known and very general pattern of covariation between leaf traits, the "worldwide leaf economic spectrum".  This hypothesis explains this pattern as a consequence of "design constraints" on how leaves of vascular plants are constructed.  Finally, my students and I will refine and test a new method of quantifying one important environmental selection agent (soil fertility) which is a fundamental environmental selection agent in plant ecology.