Understanding biodiversity maintenance and change across local, regional and global forests

关于生物多样性维持和景观变化的知识对于预测生态系统对自然和人为干扰的反应至关重要，从而为生物多样性保护和管理提供信息。然而，目前关于生物多样性变化的证据是模棱两可的，对维持或驱动生物多样性变化的机制的理解仍然有限。该提案将通过开展创新研究计划来解决这些知识差距。本研究以两个长期且设计良好的全球森林清查样地网络（CTFS-ForestGEO和国家森林清查样地）为基础，将采用观测、实验和分析方法：测试生物多样性维持机制；制定评估生物多样性变化的方法；并分析长期和全球森林动态数据，以综合理解生物多样性和生态系统功能的变化。首先，本提案将解决四个相互关联的研究组成部分，这些组成部分对理解景观中生物多样性的维持和变化至关重要。(1)测试土壤传播病原体在调节当地森林多样性，特别是稀有物种种群中的作用。将开展基于田间的变暖实验，以测试全球变暖如何影响土壤病原体与植物宿主的相互作用，从而了解气候变化对病原体调节的生物多样性的潜在影响。(2)建立具有统计学意义和生态意义的生物多样性变化评估方法，并应用这些方法对两个全球森林样地的数据进行分析，以发现从局部到全球尺度的生物多样性变化信号。(3)量化竞争和气候对森林动态的相对重要性，特别关注竞争和气候相互作用的建模，以了解气候变化如何调节全球森林中的树木竞争。(4)模拟全球森林树木人口统计学速率（生长、死亡和补充）与生态系统功能之间的关系。与关注生物多样性-生态系统功能关系的广泛采用但有争议的研究方法相反，该分析将生态系统功能与树木人口统计过程联系起来。这一分析结果有望为森林动态对生态系统功能的影响提供新的机制认识。****该研究项目将提供关于生物多样性维持机制的新知识，并将在空间尺度上为全球森林生物多样性变化（或无变化）提供证据。这项工作所产生的概念、模型、方法和综合将提高我们理解和预测气候和土地利用变化对森林动态和功能的影响的能力，从而更好地保护和管理生物多样性。*********

Knowledge on biodiversity maintenance and change in landscapes is essential for predicting ecosystem responses to natural and anthropogenic disturbances, thus informing biodiversity conservation and management. However, current evidence on diversity change is equivocal and understanding of the mechanisms that maintain or drive changes in biodiversity remains limited. This proposal will address these knowledge gaps by undertaking an innovative research program. Built on two long-term and well-designed global networks of forest inventory plots (the CTFS-ForestGEO and National Forest Inventory plots), this research will take observational, experimental and analytical approaches to: test mechanisms of biodiversity maintenance; develop methods for assessing biodiversity change; and, analyze long-term and global forest dynamic data to synthesize understanding of changes in biodiversity and ecosystem functioning. Primarily, this proposal will address four interrelated research components critical to understanding biodiversity maintenance and change in landscapes. (1) Testing the role of soil-borne pathogens in regulating local forest diversity, particularly rare species populations. Field-based warming experiments will be conducted to test how global warming may affect soil pathogen-plant host interactions for understanding potential impacts of climate change on pathogen-regulated biodiversity. (2) Developing statistically sound and ecologically meaningful methods for assessing biodiversity change, and applying these methods to analyze data from the two global forest plots to detect signals of biodiversity change from local to global scales. (3) Quantifying the relative importance of competition and climate to forest dynamics, with a special interest in modeling the interaction of competition and climate for understanding how climate change may mediate tree competition in forests worldwide. (4) Modeling the relationships between tree demographic rates (growth, mortality and recruitment) and ecosystem functioning across global forests. In contrast with the widely adopted but controversial research approach that focuses on biodiversity-ecosystem functioning relationships, this analysis will link ecosystem function with tree demographic processes. Results from this analysis are expected to provide new mechanistic understanding of the effect of forest dynamics on ecosystem functioning.**** This research program will contribute new knowledge on the mechanisms of biodiversity maintenance and will provide evidence on global biodiversity change (or no change) in forests across spatial scales. The concepts, models, methods and syntheses developed as a result of this work will enhance our ability to understand and predict the impact of climate and land-use change on forest dynamics and functioning for better conservation and management of biodiversity.*********