Ecological and evolutionary responses of plants to environmental change

植物种群和群落对环境变化的响应涉及生态和进化过程之间的相互作用。 了解这些过程是一项基本的科学挑战，并决定了我们预测和管理人类所依赖的自然生态系统的能力。 生物体的特征（例如，它们的大小或开花时间）决定了环境条件如何影响性能。 由于这些特征在物种内部和物种之间都有所不同，它们为评估生态进化对环境变化的反应提供了一种天然的共同货币。 在物种内部，生物体的反应涉及两个过程：表型可塑性，它可以使开花时间等性状对当地条件迅速作出反应（例如，在一个生长季节内），以及适应性进化，这需要足够的时间出生和死亡，以导致种群水平的遗传变化。 表型可塑性使我们很容易通过时间明确地跟踪进化变化的能力变得复杂，而且，不同种群中的可塑性反应可以影响这些种群之间的基因流动，从而影响局部适应。 本文提出的研究旨在评估这些过程在自然界中的作用，测试有关植物种群和群落对环境变化的反应相对未被探索的方面的关键假设。我提出了三条调查路线的基础上的植物种群和群落的落叶到北方森林的梯度与海拔在魁北克省南部：（1）评估的决定因素的相对作用，物种营业额，表型可塑性和当地适应在创建社区水平的特征环境匹配。 这将通过对物种内部和物种之间的地上和地下植物特征进行深入观察研究，以及在4-5个草本物种中进行跨海拔的相互移植实验来实现。(2)检验气候变暖导致不同海拔地区种群开花时间差异的假设，从而减少基因流，影响适应性进化。该项目包括密集的开花物候观测沿着梯度，基因流的分子标记分析，和实验评估的性能的后代来自内部和种群间交配。(3)对糖枫树（主要落叶树）在最大变暖期间（过去50年）基于遗传的进化变化进行明确测试，使用“跨时间的共同花园”（通过不同年龄树木的插条产生）和对已知与气候相关的基因进行分子分析的创新组合。这项研究有望为生物对环境变化的反应提供新的独特见解，这是当前最紧迫的科学挑战之一。

The responses of plant populations and communities to environmental change involve interactions between ecological and evolutionary processes.  Understanding these processes presents a fundamental scientific challenge and determines our ability to predict and manage the natural ecosystems upon which people depend.  The traits of organisms (e.g., their size, or time of flowering) determine how environmental conditions influence performance.  Because such traits vary both within and among species, they provide a natural common currency for assessment of eco-evolutionary responses to environmental change.  Within species, organismal responses involve two processes: phenotypic plasticity, which can allow traits such as flowering time to respond rapidly to local conditions (e.g., within a single growing season), and adaptive evolution, which requires sufficient time for birth and death to result in genetic change at the population level.  Phenotypic plasticity complicates our ability to easily track evolutionary change explicitly through time, and moreover, plastic responses in different populations can influence gene flow between those populations, and thus local adaptation.  The research proposed here aims to assess the action of these processes in nature, testing key hypotheses concerning relatively unexplored aspects of plant population and community responses to environmental change.***I propose three lines of inquiry based on the plant populations and communities of the deciduous-to-boreal forest gradient with elevation in southern Québec: (1) Assessing the determinants of the relative roles of species turnover, phenotypic plasticity and local adaptation in creating community-level trait-environment matching.  This will be achieved using an in-depth observational study of above- and below-ground plant traits, within and among species, coupled with reciprocal-transplant experiments across elevations in 4-5 herbaceous species. (2) Testing the hypothesis that warming causes divergence in flowering time among populations at different elevations, thereby reducing gene flow, and affecting adaptive evolution. This project involves intense observations of flowering phenology along the gradient, molecular-marker analyses of gene flow, and experimental assessment of the performance of offspring derived from intra- and inter-population mating. (3) An explicit test for genetically-based evolutionary change in sugar maple (the dominant deciduous tree) over the period of maximal warming (the past 50 years) using an innovative combination of a `common garden across time' (generated via cuttings from trees of different age) and molecular analysis of genes with known links to climate associations. This research promises new and unique insights into biotic responses to environmental change, one of the most pressing current scientific challenges.********