Diversity and ecosystem functions of boreal forest under global changes

气候和土地利用变化是全球陆地生物多样性和生态系统功能的两大压力源。了解气候土地利用变化对生物多样性和生态系统功能的影响，对于环境科学的理论进步以及人类社会的缓解和适应战略至关重要。我的长期目标是了解气候和土地利用变化如何以及为什么影响加拿大北方森林的多样性和功能。一种有希望的方法是利用自然实验来了解导致真实生态系统生物多样性和功能变化的机制。在接下来的五年里，我将结合加拿大大地理区域长期反复测量的森林样地和精心设计的自然实验样本，确定导致加拿大北方森林多样性和功能变化的机制。我的具体目标是研究(i)全球气候变化如何以及为什么影响北方森林生物量碳功能、树种多样性以及多样性与功能之间的关系。特别是，我将讨论物种多样性是否减轻了气候变化的负面影响（增加干旱和虫害爆发）和/或增强了积极影响，如氮沉积和二氧化碳上升对碳功能的影响；（ii）物种多样性对地下功能的影响可能因林分发育而异；(3)火灾后补救性采伐影响树木再生、植物物种多样性和碳功能。拟议的工作将增进我们对人类对北方森林影响的认识，并将在气候和土地利用迅速变化的时代训练几个HQP。我们的研究结果可能对了解两种最大的生态系统压力源对北方生态系统的影响以及帮助社会制定缓解和适应战略具有重要意义。

Climate and land-use changes are the two greatest stressors for global terrestrial biodiversity and ecosystem function. Understanding the impacts of climate land-use changes on biodiversity and ecosystem function is central to the theoretical advances in environmental sciences and to mitigation and adaption strategies of human society. My long-term goal is to understand how and why climate and land-use changes affect the diversity and function of Canada’s boreal forests. One promising approach is to use natural experiments to understand the mechanisms leading to the changes in biodiversity and function of real ecosystems. In the next five years, by combining long-term repeatedly measured forest plots over large geographic areas in Canada with carefully designed sampling of natural experiments, I will identify the mechanisms responsible for the changes in diversity and function of Canada’s boreal forests. My specific aims are to investigate how and why (i) global climate change impacts boreal forest biomass carbon function, tree species diversity, and the relationship between diversity and function. In particular, I will address whether species diversity mitigates negative impacts of climate change (increased drought and insect outbreaks) and/or enhances positive effects such as nitrogen deposition and rising CO2 on carbon function; (ii) species diversity effects on belowground function may differ with stand development; (iii) post-fire salvage logging affects tree regeneration, plant species diversity and carbon function. The proposed work will advance our knowledge of human influences on boreal forests and will train several HQP in the era of rapid climate and land-use changes. Our results are likely to be of great importance in understanding the impact of the two greatest ecosystem stressors on boreal ecosystems and in helping society to develop mitigation and adaptation strategies.