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，从而为生物多样性的养护和管理提供信息。然而，目前关于生物多样性变化的证据是模棱两可的，对维持或推动生物多样性变化的机制的了解仍然有限。这项提案将通过开展一项创新研究计划来解决这些知识差距。这项研究建立在两个长期和设计良好的全球森林调查样地网络(CTFS-ForestGEO和国家森林调查样地)的基础上，将采取观察、实验和分析的方法来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；以及分析长期和全球森林动态数据，以综合了解生物多样性和生态系统功能的变化。首先，这项提案将涉及四个相互关联的研究组成部分，这些组成部分对于了解生物多样性的维持和景观变化至关重要。(1)测试土传病原体在调节当地森林多样性，特别是稀有物种种群方面的作用。将进行田间变暖实验，以测试全球变暖如何影响土壤病原体-植物寄主之间的相互作用，以了解气候变化对病原体调节的生物多样性的潜在影响。(2)发展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，以检测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，特别是对竞争和气候的相互作用进行建模，以了解气候变化如何调节全球森林中的树木竞争。(4)模拟全球森林的树木人口率(生长、死亡和补充)与生态系统功能之间的关系。与广泛采用但有争议的研究方法不同，这种研究方法侧重于生物多样性-生态系统功能关系，这种分析将把生态系统功能与树木人口统计过程联系起来。这一分析的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理解。*这项研究计划将为生物多样性维持机制提供新的知识，并将为全球森林生物多样性在空间尺度上的变化(或不变化)提供证据。这项工作产生的概念、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的影响以及更好地保护和管理生物多样性的作用的能力。

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.*********