From plant traits to vegetation structure/Des traits des végétaux à la structure de la végétation

从植物性状到植被结构/Des Traits des Végétaux à la Structure de la Végétation

• 批准号: RGPIN-2014-05989
• 负责人: Shipley, JohnWilliam
• 金额: $ 3.64万
• 依托单位: Université de Sherbrooke
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=567514
• 关键词: plant; traits; vegetation; structure; Des

I view community assembly as a selection process occurring at the level of individuals belonging to different species, based on the adaptive fit of functional traits to prevailing environmental filters. This general framework, continued in this proposal, has been pursued using a combination of comparative experiments under controlled conditions, manipulative field experiments, observational studies along environmental gradients and mathematical modelling. The general goal of my research program is to answer the following general questions: Given a regional species pool (a list of plant species that are found in a region), a knowledge of the values of key functional traits of these species, and the environmental conditions found in a local community within this region, which species from the species pool will be found at this site? Which of these species will be dominant, subdominant or rare? How will the answers to the first two questions change if we were to change the position of this local community along important environmental gradients? How does the multivariate distribution of trait values within a community affect important ecosystem properties like primary productivity, nutrient cycling and litter decomposition? I recently (2010) published the general theoretical model of my understanding of trait-based community assembly (“From plant traits to vegetation structure: Chance and selection in the assembly of ecological communities”, Cambridge U Press). In this next 5-year proposal my students and I will be testing and expanding this understanding based on five specific research projects. A current PhD student (Jessy Loranger) will use a unique set of 11 long-term field experiments throughout France, involving community composition, plant traits and environmental gradients, to test my general model (“CATS: Community Assembly by Trait Selection”). A second PhD student (Michaël Belluau) will conduct a series of controlled experiments involving 40 contrasted herbaceous dicots, field observations, and multivariate modelling to better link multiple correlated patterns in leaf economic traits and plant hydraulic architecture to precisely measured levels of water stress. This is currently a relatively poorly studied stress in herbaceous species. A third PhD student (Yuanzhi Li) will be exploring a little-recognized implication of trait-based community assembly that is linked to the classical notion of limiting similarity: if communities are assembled while requiring a certain minimum amount of overlap in multivariate trait-space, then the total area of trait-space occupied by communities must expand as species richness increases. Yuanzhi will test these ideas using an existing long-term replicated experiment involving 24 1X1X1 m3 field mesocosms that initially received the same seed mixture but that differ in levels of soil fertility as well as the intensity and frequency of disturbance. The last two projects involve students yet to be recruited. One MSc student will conduct field and mesocosm experiments by manipulating soil water availability in order to test whether the trait syndromes related to water stress of actual and created plant communities, identified by Michaël Belluau (PhD student) change as predicted. A second MSc student will measure ecosystem responses (primary productivity, nutrient loss and litter decomposition) in the longterm mesocosm experiment and relate these responses to differences in community weighted trait values and their variance. These research projects will contribute to the longterm goal of predicting plant community structure and functioning from generalizable plant traits.

我认为群落聚集是发生在不同物种的个体水平上的选择过程，其基础是功能特征对主流环境过滤器的适应性匹配。这一总体框架，在本建议中继续，是通过在受控条件下的比较实验、可操作的实地实验、沿环境梯度的观察研究和数学模型的组合来实现的。我的研究计划的总体目标是回答以下一般性问题：给定一个区域物种库（一个地区发现的植物物种列表），了解这些物种的关键功能特征值，以及该地区当地群落中发现的环境条件，物种库中的哪些物种将在该地点发现？这些物种中哪一个是显性的，次显性的还是稀有的？如果我们沿着重要的环境梯度改变当地社区的位置，前两个问题的答案将如何改变？群落内性状值的多元分布如何影响初级生产力、养分循环和凋落物分解等重要生态系统特性？我最近（2010）发表了我对基于性状的群落组装的一般理论模型（“从植物性状到植被结构：生态群落组装中的机会和选择”，剑桥U出版社）。在接下来的五年计划中，我和我的学生将基于五个具体的研究项目来测试和扩展这种理解。一名在读博士生（Jessy Loranger）将在法国各地进行一套独特的11项长期野外实验，涉及群落组成、植物性状和环境梯度，以测试我的一般模型（“CATS：性状选择的群落组装”）。另一名博士生（Michaël Belluau）将进行一系列对照实验，涉及40种对照草本植物，实地观察和多元模型，以更好地将叶片经济性状和植物水力结构的多种相关模式与精确测量的水分胁迫水平联系起来。这是目前在草本物种中相对较少研究的压力。第三位博士生（李元志）将探索一个鲜为人知的基于性状的群落组装的含义，这与限制相似性的经典概念有关：如果群落在多元性状空间中组装时需要一定的最小重叠量，那么群落所占据的性状空间总面积必须随着物种丰富度的增加而扩大。Yuanzhi将通过一项现有的长期重复实验来验证这些想法，该实验涉及24个1X1X1 m3的农田中生态系统，这些中生态系统最初接受相同的种子混合物，但土壤肥力水平以及干扰的强度和频率不同。最后两个项目涉及的是尚未招募的学生。一名硕士研究生将通过操纵土壤水分有效性进行田间和中观实验，以测试Michaël Belluau（博士生）确定的与实际和创造的植物群落的水分胁迫相关的性状综合征是否如预测的那样变化。另一名硕士研究生将在长期中生态实验中测量生态系统反应（初级生产力、养分损失和凋落物分解），并将这些反应与群落加权性状值及其方差的差异联系起来。这些研究项目将有助于从广义植物性状预测植物群落结构和功能的长期目标。