Fundamental drivers of plant spectral diversity

植物光谱多样性——植物物种的叶片如何与太阳辐射发生不同的相互作用——是生物多样性中一个非常有前途但仍不为人知的方面。植物光谱多样性是植物系统发育和功能多样性的一个强大的集成器，它可以直接遥感到植物光谱多样性，因此受到人们的高度关注。因此，一个名为“光谱组学”的新领域正在彻底改变我们获取大区域高分辨率生物多样性数据的方式。然而，我们对不同物种和环境下叶片光谱变化的基本驱动因素知之甚少。我的研究计划的总体目标是确定植物物种、群落和土壤肥力梯度内部和之间叶片光谱变化的基本驱动因素。该研究项目建立在我之前的“基于性状的植物生态学研究”的基础上，并在光谱多样性及其与系统发育和功能多样性的联系方面开辟了令人兴奋的新研究方向。中心假设是叶片光谱变化主要由系统发育决定，其次由环境决定。该研究项目围绕三个短期目标展开。在第一个目标中，我将确定物种间叶片光谱变化的基本轴。在这里，我将测试光谱变化沿着三个主要轴组织的假设，表示：(1)叶片经济光谱，(2)化学和结构防御之间的权衡，以及(3)叶片水力光谱。为此，我将利用我们在澳大利亚的土壤时间序列网络，对分布在广泛的地理和气候梯度上的大量冠层植物物种的光谱和特征进行大规模的实地调查。我的第二个目标是量化植物物种的光谱可塑性程度。具体来说，我将验证具有更广泛的生态位的物种表现出更高的光谱可塑性的假设。为此，我将结合长期土壤时间序列的实地观察和跨越大土壤肥力梯度的普通花园实验，提供迄今为止最全面、最严格的叶片光谱可塑性量化。最后，我的第三个目标是确定跨肥力梯度的群落内部和群落之间叶片光谱多样性的驱动因素。特别是，我将检验群落水平上光谱多样性在土壤肥力梯度上的变化表达植物分类和功能多样性变化的假设。这项研究将沿着澳大利亚朱连湾土壤时间序列进行，这是有史以来最强的自然土壤肥力梯度之一。通过揭示植物物种和环境中叶片光谱变化的基本驱动因素，我的研究将为未来的光谱组学全球生物多样性观测站铺平道路。

Plant spectral diversity -how leaves of plant species differentially interact with solar radiation- is a highly promising but still largely unknown facet of biodiversity. Plant spectral diversity is of high interest because it can be directly remotely sensed, and because it is a powerful integrator of plant phylogenetic and functional diversity. As a result, a new field called "spectranomics" is revolutionizing how we acquire high-resolution biodiversity data over large regions. However, we still know little about the basic drivers of leaf spectral variation across species and environments. The overall objective of my research program is to determine the fundamental drivers of leaf spectral variation within and among plant species, communities, and across soil fertility gradients. The proposed research program builds from my previous Discovery Grant in trait-based plant ecology along natural soil fertility gradients, and develops exciting new research directions about spectral diversity and its linkages with phylogenetic and functional diversity. The central hypothesis is that leaf spectral variation is primarily determined by phylogeny, and secondarily by the environment. The research program is organised around three shorter-term objectives. In the first objective, I will identify fundamental axes of leaf spectral variation among species. Here, I will test the hypothesis that spectral variation is organised along three major axes expressing: (1) the leaf economics spectrum, (2) a trade-off between chemical and structural defences, and (3) a leaf hydraulics spectrum. To do so, I will conduct a large-scale field survey of spectra and traits for a large number of canopy plant species spread across broad edaphic and climatic gradients, using our network of soil chronosequences in Australia. My second objective is to quantify the degree of spectral plasticity within plant species. Specifically, I will test the hypothesis that species with broader edaphic niches show higher spectral plasticity. To do so, I will use a combination of field observations along long-term soil chronosequences and common garden experiments spanning large soil fertility gradients to provide the most comprehensive and rigorous quantification of leaf spectral plasticity to date. Finally, my third objective is to determine the drivers of leaf spectral diversity within and among communities across fertility gradients. In particular, I will test the hypothesis that community-level shifts in spectral diversity across soil fertility gradients express changes in plant taxonomic and functional diversity. This research will be conducted along the Jurien Bay soil chronosequence in Australia, which is one of the strongest natural soil fertility gradients ever described. By unravelling the fundamental drivers of leaf spectral variation across plant species and environments, my research will pave the way for a future global biodiversity observatory informed by spectranomics.