Advancing trait-based plant ecology: understanding the causes and consequences of trait covariation across biological scales

由于人为的环境变化正在导致第六次大灭绝，生态学在社会中的地位比以往任何时候都更加重要。研究约900万个具有独特基因和性状的物种，普遍性既是生态学的中心目标也是挑战。为此，植物生态学最近转向了一种基于性状的方法。通过测量所有植物的共同特征，这种方法为比较物种提供了一种通用的货币。基于性状的植物生态学通过描述世界范围内植物形态变异的主要轴和功能组织多样性的性状维度，每个维度代表多个相关性状，在提高普遍性方面取得了重大进展。我的研究突出了我们对局部尺度性状共变的理解中的两个关键空白，本研究将解决这两个空白。我的计划的长期目标是提高我们的生态和进化的理解(i)的原因和（ii）植物性状共变跨生物尺度的后果。

As anthropogenic environmental changes are leading to a 6th mass extinction, Ecology's place in society is more central than ever. Studying ~9 million species with unique genes and traits, generality is both a central goal and challenge of ecology. To that end, plant ecology has recently shifted toward a trait-based approach. Measuring traits common to all plants, this approach provides a common currency to compare species. Trait-based plant ecology has made significant progress toward improving generality by describing trait dimensions, major axes of variation in plant form and function organizing diversity worldwide, each representing multiple correlated traits. My research has highlighted two crucial gaps in our understanding of trait covariation at local scales which this research will address. The long-term goal of my program is to improve our understanding of the ecological and evolutionary (i) causes and (ii) consequences of plant trait covariation across biological scales. First, strong at global scales, trait dimensions can disappear at more local scales and we do not know why. We do not know how local-scale processes affect the mechanisms underpinning global patterns of trait covariation. Second, the effects of trait-trait interactions on plant performance across environments is currently not taken into account in trait-based ecology. To address these gaps, I will examine the coordination among carbon- and water-use traits in model, crop and commercial temperate tree species. My short-term objectives (O) are to: O1. Determine the local causes of intraspecific covariation in carbon-use foliar traits; O2. Assess the role of water-use traits in modulating relationships among carbon-use foliar traits; O3. Assess how intraspecific covariation in carbon- and water-use traits constrain the response of tree species to climate change. The research is of broad interest for ecology and evolution as, no matter the results, it will produce globally significant advances in our understanding of the causes of trait-function relationships across scales. O1 uses an innovative cross-scale approach rarely adopted in ecology that assesses the relative role of different causes of integration. O2 is novel because trait-based ecology has paid little attention to how water-use traits affect relationships among carbon-economic traits, shown to affect ecological processes from tree growth to ecosystem function. O3 will improve our ability to predict how trees respond to climate change, which is essential to mitigate the effects of climate change on forest ecosystems. Covering over 40% of Canada and strongly impacted by climate change, forests provide the basic habitats for other organisms and are a resource critical to the forestry industry and social well-being of Canadians. Trainees will gain valuable professional and technical skills in ecology and ecophysiology that will advance their careers in consulting, scientific communication, education or research.