Unravelling the effects of climate, composition and disturbance on forest productivity in the eastern boreal forest

揭示气候、成分和干扰对东部北方森林森林生产力的影响

• 批准号: RGPIN-2017-06616
• 负责人: Kneeshaw, Daniel
• 金额: $ 3.5万
• 依托单位: Université du Québec à Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=655745
• 关键词: Unravelling; effects; climate; composition; disturbance

Changing climate, disturbance regimes and their interactions are modifying ecosystem dynamics especially in high latitude forests; my long-term objective is to evaluate changes in decades of growth, population and community dynamics of the dominant tree species across a large region of the eastern boreal. Specifically, I will combine growth patterns derived from a province wide collection of tree ring cores to study climate sensitivity of the growth of boreal trees across large environmental gradients. We will investigate both species and site-level within species responses. Another short-term objective is to evaluate long-term changes in population (mortality vs recruitment) and community (changes in composition) dynamics of these same species along east-west (precipitation) and north-south (temperature) gradients. As insects are ectotherms they should also react strongly to warming and may interact with moisture stresses that predispose trees to increased mortality. With range expansion of the spruce budworm, an outbreaking insect, mixes of species that are rare in its traditional range will be increasing under attack. The effects of associational relationships (increased resistance vs susceptibility) in different mixes of boreal tree species will be used as a proxy for resilience to abiotic (climate) and biotic (insects) stresses in boreal forest systems at different spatial scales.******To answer these questions, my graduate students and I will combine a large data base of more than 365 000 tree cores collected from across the province with a temporal series of aerial photos taken systematically every decade since 1945. We will also use defoliation and species mixing data from permanent sample plots established at the beginning of the current spruce budworm outbreak. Coupled with geomorphological data bases and climatic data for the last 70 years we will evaluate the effect of climate by site type on the growth and population dynamics of each species******Combining temporal and spatial analyses of tree changes will allow us to better explain the influence of recent changes in climate on forest composition and productivity and to then predict future change. By exploring species responses over large temporal and scale scales with multiple tree species this work will also allow me to further our understanding of between species vs within species site-level variability in tree responses to climate change. Most current approaches evaluate one response variable at a time (i.e. growth, or mortality). A multi-pronged approach applied to the boreal forest will permit us to more fully evaluate the real effects of climate change on the productivity of an ecosystem that has undergone some of the largest climatic changes.

不断变化的气候、干扰机制及其相互作用正在改变生态系统动态，特别是在高纬度森林；我的长期目标是评估东部北部大片地区优势树种几十年来的生长、种群和群落动态的变化。具体地说，我将结合从全省范围内收集的树木年轮核心得出的生长模式来研究大环境梯度下北方树木生长的气候敏感性。我们将调查物种和物种内的站点水平的反应。另一个短期目标是评估这些相同物种沿东西(降水)和南北(温度)梯度的种群数量(死亡率与补充量)和群落(组成变化)动态的长期变化。由于昆虫是外温动物，它们也应该对气候变暖做出强烈反应，并可能与使树木更容易死亡的水分压力相互作用。云杉幼虫是一种暴发的昆虫，随着其活动范围的扩大，在其传统活动范围内罕见的物种混合将会越来越多地受到攻击。不同混交的北方树种的联合关系(增加的抗性与敏感性)的影响将被用来在不同的空间尺度上代表北方森林系统对非生物(气候)和生物(昆虫)胁迫的恢复能力。为了回答这些问题，我和我的研究生们将把从全省收集的超过365,000个树心的大型数据库与自1945年以来每十年系统地拍摄一次的时间系列航空照片结合在一起。我们还将使用在当前云杉潜蝇暴发开始时建立的永久样地的落叶和物种混合数据。结合地貌数据库和过去70年的气候数据，我们将评估按立地类型划分的气候对每个物种生长和种群动态的影响*结合树木变化的时间和空间分析，将使我们能够更好地解释最近气候变化对森林组成和生产力的影响，并预测未来的变化。通过探索多树种在大时间和大尺度上的物种响应，这项工作也将使我进一步理解树种对气候变化响应的物种间和物种内立地水平的变异性。目前的大多数方法一次只评估一个反应变量(即增长或死亡率)。将多管齐下的方法应用于北方森林，将使我们能够更充分地评估气候变化对经历了一些最大气候变化的生态系统生产力的实际影响。