Species assembly in vegetation under a changing climate: plant traits, contested resources, and community consequences

保护和恢复生态学的一个基本目标是理解为什么某些地方的物种丰富度和植被生产力高于其他地方的机制。这个问题的答案对于做出与植被对快速气候变化的反应有关的明智预测和建议至关重要。在我研究计划的第一个主要部分，我将探索一种思考植物竞争能力的新方式——一种认识到竞争下的适应性不仅仅涉及生长（植物大小）和生存；最重要的是，它还涉及到生育后代。项目将研究植物分生组织/芽的分布和分配如何影响竞争下适应性的所有三个组成部分——植物大小、存活率和繁殖力，并将测试如何使用这些预测来定义一个理论，在不要求它们弱竞争的情况下，在不需要异质物理环境的情况下，许多物种共存。在我的研究计划的第二个组成部分中，上述基于多性状的植物竞争能力方法将在水资源竞争的特定背景下进行测试，在沿着环境梯度的自然植被中长期田间地块进行资源操纵实验。在世界范围内，水是种植系统中最重要的限制性资源和竞争对象。预测者预测，由于气候变化和其他人为影响，21世纪对水供应的担忧将与上世纪对石油供应的担忧一样。我预测，即使在非干旱环境中，水也是影响植物竞争和植物群落结构和组装的最具限制性的资源，而植被生态学的绝大多数研究和理论都强调光和养分的竞争是自然植被生物量生产的最重要的竞争和限制对象。这个研究项目将解决这种不平衡。

A fundamental goal for conservation and restoration ecology is to understand the mechanisms that explain why the species richness and productivity of vegetation are greater in some places than in others. Answers to this question are essential for making informed predictions and recommendations associated with vegetation response to rapid climate change. In the first major component of my research program, I will explore a new way of thinking about competitive ability in plants - one that recognizes that fitness under competition involves more than just growth (plant size) and survival; it also involves, most importantly, producing offspring. Projects will examine how the deployment and allocation of plant meristems / buds affects all three components of fitness under competition - plant size, survival and fecundity, and they will test predictions about how these can be used to define a theory for the coexistence of many species without requiring that they compete weakly, and without requiring a heterogeneous physical environment. In the second component of my research program, the above multi-trait-based approach to plant competitive ability will be tested in the specific context of competition for water using resource manipulation experiments within long-term field plots in natural vegetation along environmental gradients. On a world-wide scale, water is the most significant limiting resource and object of competition in cropping systems. Forecasters predict that, because of climate change and other anthropogenic effects, concerns for water supply in the 21st century will be what oil supply was in the last century. I predict that water is the most limiting resource affecting plant competition and plant community structure and assembly even in non-arid environments, yet the vast majority of studies and theory in vegetation ecology emphasize competition for light and nutrients as the most important objects of competition and limitation on biomass production in natural vegetation. This research program will address this imbalance.