Mechanisms of species assembly and coexistence in vegetation under a changing climate: Plant traits, contested resources, and ecosystem services

气候变化下植被物种组装和共存机制：植物性状、竞争性资源和生态系统服务

• 批准号: RGPIN-2014-03684
• 负责人: Aarssen, Lonnie
• 金额: $ 2.48万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632067
• 关键词: Mechanisms; species; assembly; coexistence; vegetation

A fundamental goal for conservation & restoration ecology is to understand the mechanisms that explain why species composition, richness & productivity of natural vegetation vary across space & time. Answers to these questions are essential for making informed predictions and recommendations for mitigation associated with vegetation response to ongoing climate change (precipitation & temperature), atmospheric pollution (nitrogen inputs), success of invasive species, and habitat & species loss from impacts of a burgeoning human population that is destined to continue increasing in size and density in the coming decades. Faced with this, we also need to learn how to anticipate what we can expect from the emergent properties & services of the ecosystems of tomorrow as they are shaped in new ways by powerful, persistent and growing forces of anthropogenic selection. Because reproductive success of resident plants in most natural vegetation is routinely limited by near-neighbour effects, guidance in support of the above goals will require a deep understanding of the selection consequences of species interactions. Accordingly, the research program proposed here-with collaboration involving training for 9 graduate students & 15 undergraduate students-will test recent hypotheses about the key plant traits that affect success in leaving descendants in crowded vegetation (competitive ability), and under heavy impact of browsing from a continuing population explosion of white-tailed deer in eastern Ontario-and will examine the role of water versus nutrients as key objects of soil resource competition in mesic habitats that are predicted to become more nitrogen-enriched plus wetter or more arid as climate change unfolds, and as these effects (modulated by species interactions) impact on community structure, diversity and productivity. Competition between near neighbours is conventionally regarded as one of the most intense forces of natural selection that has shaped the species composition, diversity & evolution of plant traits across the globe. Traditional theory is based on a `size-advantage' (SA) hypothesis-i.e. intense competition between plants generally selects for a strategy that includes capacity to grow to a relatively large body size. My research program will explore a paradox-a disconnect with the SA hypothesis: most resident species are relatively small within virtually all vegetation types. I will develop and investigate a paradigm shift for understanding competitive ability in plants-one that recognizes that fitness (gene transmission) under competition involves more than just growth (plant size) & 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-size, survival & fecundity. They will test predictions about interactions and trade-offs between these three fitness components, and how these can be used to define revisions for species coexistence theory that do not depend on weak competition (through traditional niche differentiation or effects of disturbance), and without requiring a heterogeneous physical environment. Since meristem production is tied directly to leaf production, this research will also develop more broadly into a series of studies based on a novel meristem-based approach for defining plant strategies in terms of 'leafing intensity' (e.g. size/number) trade-offs and 'reproductive economy' (ability to deploy reproductive meristems successfully despite severe plant size suppression). This approach will be tested across a wide range of life forms (herbaceous & woody), and at several scales ranging from within-plant to between-taxa, and across habitat types.

保护与恢复生态学的一个基本目标是了解解释自然植被的物种组成、丰富度和生产力在空间和时间上变化的机制。这些问题的答案对于做出明智的预测和建议至关重要，这些预测和建议与植被对持续气候变化（降水和温度），大气污染（氮输入），入侵物种的成功以及栖息地和物种损失的影响有关。面对这一点，我们还需要学习如何预测我们可以从明天生态系统的新兴特性和服务中期待什么，因为它们是由强大的，持久的和不断增长的人为选择力量以新的方式塑造的。 由于在大多数自然植被中，常驻植物的繁殖成功通常受到近邻效应的限制，因此支持上述目标的指导将需要深入了解物种相互作用的选择后果。因此，这里提出的研究计划-包括培训9名研究生和15名本科生-将测试最近关于影响在拥挤植被中留下后代成功的关键植物性状的假设（竞争力），在安大略东部白尾鹿数量持续激增的严重影响下，并将研究水与营养物作为土壤资源竞争的关键对象在中温带生境中的作用，预计随着气候变化的展开，这些生境将变得更加富氮，更加湿润或更加干旱，这些影响（由物种相互作用调节）对群落结构、多样性和生产力产生影响。 近邻之间的竞争通常被认为是自然选择中最激烈的力量之一，它塑造了地球仪的物种组成，多样性和植物性状的进化。传统的理论是基于“大小优势”（SA）假设，即植物之间的激烈竞争通常会选择一种策略，包括生长到相对较大的身体大小的能力。我的研究计划将探讨一个悖论与SA假说脱节：大多数居民物种相对较小，几乎所有的植被类型。我将开发和研究一个范式转变，以了解植物的竞争能力，一个认识到，健身（基因传递）在竞争下涉及的不仅仅是增长（植物大小）和生存;它还涉及，最重要的是，产生后代。项目将研究植物分生组织/芽的部署和分配如何影响竞争下的大小，生存和繁殖力的健身的所有三个组成部分。他们将测试关于这三个健身组件之间的相互作用和权衡的预测，以及如何使用这些来定义不依赖于弱竞争（通过传统的生态位分化或干扰效应）的物种共存理论的修订，并且不需要异质的物理环境。由于分生组织的生产直接关系到叶的生产，这项研究也将更广泛地发展成一系列的研究的基础上，一种新的分生组织为基础的方法来定义植物策略的“生叶强度”（如大小/数量）的权衡和“生殖经济”（能够部署生殖分生组织成功，尽管严重的植物大小抑制）。这种方法将在广泛的生命形式（草本和木本）中进行测试，并在几个尺度上进行测试，从植物内部到类群之间，以及栖息地类型。