From cells to biomes: the impacts of recent climate change on northern ecosystems

从细胞到生物群落：近期气候变化对北方生态系统的影响

• 批准号: RGPIN-2017-04321
• 负责人: Pisaric, Michael
• 金额: $ 2.84万
• 依托单位: Brock University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=709229
• 关键词: cells; biomes; impacts; recent; climate

Climate change is leading to broad scale impacts on global ecosystems through changing temperature and precipitation patterns. For example, climate change is altering disturbance regimes, changing the seasonal patterns of precipitation, altering the frequency of extreme weather events, and changing species distributions and phenological patterns. In northern regions, the impacts of climate change are heightened due to Arctic amplification which has caused the Arctic to warm nearly 2X faster than mid-latitude regions. The rapid warming in the Arctic is leading to changes to physical and biological components of high-latitude ecosystems. For example, within the field of dendroclimatology, recent studies have noted that since the 1970-80s, there has been an increasing off-set between tree-ring temperature reconstructions and measured temperatures at some high-latitude sites. This offset between actual temperatures and those reconstructed from tree ring studies is known as the "Divergence Problem". Divergence is potentially an ecosystem response to recent climate change and challenges the assumption that tree ring chronologies can be used as a reliable predictor of past climate. In addition, the spatial extent of the Divergence Problem is largely unexplored. My research will further our understanding of climate and environmental change in northern Canada using highly-resolved proxy data sources (tree ring records). I will address the Divergence issue in tree ring research in Canada, especially the spatial occurrence of divergence across northern Canada and the potential factors leading to divergence. The main geographic areas that will be investigated are Inuvik and Norman Wells in northwest Canada;Yellowknife near the central Canadian treeline; and Churchill, MB near treeline on the coast of Hudson Bay. The specific objectives of this research project are: 1: Determine the spatial signature of the Divergence Problem across treeline in north-central Canada. 2: Determine the cause(s) of the Divergence Problem. 3: Develop long, highly resolved quantitative records of past climate for the three study regions using multiple sources of tree ring data that do not display diverging climate-growth relations. Few annually-resolved millennial length records of climate exist for Arctic/subArctic regions of Canada. I will explore the possibility of developing supra-long tree ring chronologies for northern Canada by recovering submerged logs from the bottom of lakes. 4: Explore the utility of wood anatomical features (lumen area, cell wall thickness) as proxies for reconstructing past climatic conditions at treeline sites. My research program will provide insights useful in a number of fields of study within the natural sciences (climate and ecosystem modellers, ecologists, policy analysts) and advance our knowledge of climate change and its impacts in the Arctic.

气候变化正在通过改变气温和降水模式对全球生态系统产生广泛影响。例如，气候变化正在改变扰动机制，改变降水的季节模式，改变极端天气事件的频率，改变物种分布和物候模式。在北方地区，气候变化的影响由于北极放大作用而加剧，北极变暖的速度比中纬度地区快近两倍。 北极的迅速变暖正在导致高纬度生态系统的物理和生物组成部分发生变化。例如，在 最近的研究指出，自20世纪70 - 80年代以来，树木年轮温度重建和测量之间的偏移越来越大， 一些高纬度地区的温度。这种实际温度与从树木年轮研究重建的温度之间的偏差被称为“分歧问题”。 分歧可能是生态系统对最近气候变化的反应，并挑战假设树木年轮年表可以作为可靠的 预测过去的气候。此外，发散问题的空间范围在很大程度上是未探索的。 我的研究将进一步我们在加拿大北方使用高分辨率的代理数据源（树木年轮记录）的气候和环境变化的理解。我将解决分歧的问题，在加拿大的树木年轮研究，特别是分歧的空间发生在整个加拿大北方和潜在的因素，导致分歧。将调查的主要地理区域是加拿大西北部的因纽维克和诺曼·威尔斯;加拿大中部树木线附近的耶洛奈夫;以及哈德逊湾海岸树木线附近的MB丘吉尔。该研究项目的具体目标是： 1：确定加拿大中北部树木线上发散问题的空间特征。 2：确定发散问题的原因。 第三章：开发长期的，高分辨率的定量记录，过去的气候为三个研究区域使用多个来源的树木年轮数据，不显示不同的气候增长关系。加拿大北极/亚北极地区几乎没有千年气候记录。我会研究一下 开发超长树轮年表为北方加拿大恢复淹没日志从湖底。 第四章：探索木材解剖特征（管腔面积，细胞壁厚度）的效用作为重建过去的气候条件在树线网站的代理。 我的研究计划将提供有用的见解，在自然科学（气候和生态系统建模，生态学家，政策分析师）的研究领域，并推进我们对气候变化及其在北极的影响的知识。