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.

气候变化通过改变温度和降水模式对全球生态系统产生广泛影响。例如，气候变化正在改变干扰机制，改变降水的季节模式，改变极端天气事件的频率，以及改变物种分布和物候模式。在北部地区，由于北极放大，气候变化的影响加剧，导致北极变暖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，在以下领域内 根据树木气候学，最近的研究指出，自 20 世纪 70-80 年代以来，树木年轮温度重建与测量的温度之间的偏差越来越大 一些高纬度地区的气温。实际温度与树木年轮研究重建的温度之间的这种偏差被称为“分歧问题”。 分歧可能是生态系统对最近气候变化的反应，并挑战了树木年轮年表可以用作可靠的假设 过去气候的预测者。此外，分歧问题的空间范围在很大程度上尚未得到探索。 我的研究将利用高分辨率代理数据源（树木年轮记录）进一步了解加拿大北部的气候和环境变化。我将讨论加拿大树木年轮研究中的分歧问题，特别是加拿大北部地区分歧的空间发生以及导致分歧的潜在因素。将调查的主要地理区域是加拿大西北部的伊努维克（Inuvik）和诺曼威尔斯（Norman Wells）；加拿大中部林线附近的耶洛奈夫（Yellowknife）；以及马萨诸塞州丘吉尔，靠近哈德逊湾海岸的林线。该研究项目的具体目标是： 1：确定加拿大中北部林线分歧问题的空间特征。 2：确定分歧问题的原因。 3：使用不显示不同气候-生长关系的多个树木年轮数据源，为三个研究区域开发长期、高分辨率的过去气候定量记录。加拿大北极/亚北极地区很少有每年解析的千禧年气候记录。我会探索可能性 通过从湖底回收水下原木来开发加拿大北部超长树木年轮年表。 4：探索木材解剖特征（管腔面积、细胞壁厚度）作为重建林线地点过去气候条件的代理的效用。 我的研究项目将为自然科学的许多研究领域（气候和生态系统建模者、生态学家、政策分析师）提供有用的见解，并增进我们对气候变化及其对北极影响的了解。