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是环境科学理论发展和人类社会减缓与适应战略的核心。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。一个有希望的方法是利用自然实验来了解导致生物多样性和真实的生态系统功能变化的机制。在未来的五年里，通过结合长期反复测量的森林地块在加拿大大的地理区域与精心设计的自然实验的采样，我将确定负责加拿大的北方森林的多样性和功能的变化的机制。我的具体目标是调查如何和为什么（i）全球气候变化影响北方森林生物量碳功能，树种多样性，以及多样性和功能之间的关系。特别是，我将解决物种多样性是否减轻气候变化的负面影响（增加干旱和昆虫爆发）和/或增强积极的影响，如氮沉降和二氧化碳上升对碳功能;（二）地下功能的物种多样性影响可能与林分发展不同;（三）火灾后抢救伐木影响树木再生，植物物种多样性和碳功能。拟议的工作将推进我们对人类影响北方森林的知识，并将在快速气候和土地利用变化的时代培训几名HQP。我们的研究结果可能是非常重要的，在了解两个最大的生态系统压力对北方生态系统的影响，并帮助社会制定缓解和适应战略。

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.