Assessing impacts of climate change, extreme weather events and management regimes on biogeochemical and hydrological cycles in Canadian forest ecosystems

评估气候变化、极端天气事件和管理制度对加拿大森林生态系统生物地球化学和水文循环的影响

• 批准号: RGPIN-2020-06028
• 负责人: Arain, Muhammad
• 金额: $ 3.72万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=740985
• 关键词: Assessing; impacts; climate; change; extreme

Canada's forest ecosystems, which represent about 40% or 397 Mha of the country' surface area, are being severely affected by climate change and extreme weather events such as droughts, flooding, and heatwaves. Climate warming is therein accelerating the hydrological cycle, thereby altering the growth, water balance, disturbance regimes (insect, fire), soil plant nutrient cycling and associated feedbacks (IPCC 2013, 2018). Changes in the composition, structure and functioning of forest ecosystems can affect regional climate and hence enhance the vulnerability of water resources and human communities. Developing a clear understanding of functioning of forest ecosystems and their response to climatic change and extreme events is urgently needed to maintain (or enhance) their capacity to sequester atmospheric CO2, and preserve ecosystem services. This proposal will investigate the impact of changes in forest hydrology and nutrient cycling on the carbon sequestration potential of three different age conifer and a deciduous forest and explore how these forests will respond to future climate change and extreme weather events. It will assess how different forest management treatments (e.g. variable retention harvesting (VRH)) will impact the forest growth trajectory, energy exchanges, hydrological processes in response to future climatic stresses and extreme events (e.g. drought, heat). This research will utilize ground based (e.g. eddy covariance, soil CO2 efflux, sapflow, biometric) and airborne (e.g. drone and satellite remote sensing) datasets to explore, how different age- and -species forests as well as management regimes (thinning intensities and spatial patterns) influence stand water use and productivity and response to extreme events and environmental variability. Proposal will also focus on to further develop a process- based integrated biogeochemical and hydrological model to enhance predictive capabilities of energy, water, carbon and nutrient cycles at stand and watershed scales across Canada. It will build on existing modelling work where C and N coupled Canadian Land Surface Scheme Canadian Terrestrial Ecosystem Model (CLASS-CTEM-N+) has been incorporated in the MESH Hydrological system to develop an integrated hydrological and biogeochemical model, called MESH-CTEM. Quantification of the responses of managed forests to climate change will help environmental planners to develop climate adopted forest management practices. MESH-CTEM modelling work will allow exploration of post-disturbance (management and/or fire) growth trajectories of Canadian forests under climate change in different watersheds and climate zones across Canada. Further development of CLASS and CTEM models will help to advance predictive capabilities of the Canadian regional and global climate models such as Canadian Earth System Model (Can-ESM) and provide an assessment tool to generate scenarios of future climate for policy development by the Federal Government.

加拿大的森林生态系统约占国土面积的40%或397亿公顷，正受到气候变化和干旱、洪水和热浪等极端天气事件的严重影响。因此，气候变暖加速了水文循环，从而改变了生长、水分平衡、干扰机制（虫、火）、土壤植物养分循环和相关反馈（IPCC 2013, 2018）。森林生态系统的组成、结构和功能的变化会影响区域气候，从而增加水资源和人类社区的脆弱性。迫切需要对森林生态系统的功能及其对气候变化和极端事件的反应有一个清晰的认识，以保持（或增强）森林生态系统隔绝大气二氧化碳和保护生态系统服务的能力。本研究将研究森林水文和养分循环变化对三种不同年龄针叶林和一种落叶林固碳潜力的影响，并探讨这些森林对未来气候变化和极端天气事件的响应。它将评估不同的森林管理处理（如可变保留采伐（VRH））如何影响森林生长轨迹、能量交换、水文过程，以应对未来的气候压力和极端事件（如干旱、高温）。本研究将利用地面（如涡旋相关、土壤二氧化碳外排、森林流量、生物识别）和空中（如无人机和卫星遥感）数据集来探索不同年龄和物种的森林以及管理制度（疏林强度和空间模式）如何影响林分水利用和生产力，以及对极端事件和环境变化的响应。提案还将侧重于进一步开发基于过程的综合生物地球化学和水文模型，以增强加拿大林分和流域尺度上的能源、水、碳和营养循环的预测能力。它将建立在现有的建模工作的基础上，其中C和N耦合的加拿大陆地表面方案加拿大陆地生态系统模型（CLASS-CTEM-N+）已纳入MESH水文系统，以开发一个综合水文和生物地球化学模型，称为MESH- ctem。经管理的森林对气候变化的反应的量化将有助于环境规划者制定气候适用的森林管理做法。MESH-CTEM建模工作将允许在加拿大不同流域和气候带的气候变化下探索加拿大森林的扰动后（管理和/或火灾）生长轨迹。CLASS和CTEM模式的进一步发展将有助于提高加拿大区域和全球气候模式（如加拿大地球系统模式（Can-ESM））的预测能力，并为联邦政府制定政策提供一个评估工具，以生成未来气候情景。