Climate variability and growth competition in an arctic-alpine ecosystem: retrospective growth analyses of one deciduous and one evergreen dwarf shrub in the Norwegian Scandes

高山生态系统被认为容易受到气候变化的影响。在特定恶劣条件下进化的物种可能在变暖条件下失去竞争能力，导致物种分布的范围转移，高山生态系统的结构变化，最终在某些地区，目前生长在较高高山带的物种被来自较低高山带的物种所取代。回溯性增长分析支持对未来全球变暖下高山生态系统命运的预测。在高山高山地带，木质矮灌木物种构成了生态系统的支柱。作为乔木，这种灌木形成了一年生的年轮，近年来，(矮生)灌木的树枝生态学已经成为一个新的、有前途的科学领域。在这里，我们旨在分析两个物种的生长时间、气候与生长的相互作用以及两个物种之间的竞争，一个落叶物种和一个常绿物种，作为挪威斯堪的斯低阿尔卑斯山山脊的典型例子。为此，将编制年轮宽度年表(每个物种一个年表)，并将这些生长时间序列与独特的、长期的、特定地点的微气候记录和区域气候记录进行统计比较。通过回顾生长分析来研究物种对过去和当前气候变化的响应，将揭示物种对当地气候包络的敏感性以及气候变化对它们竞争的影响。这样，它们未来对气候条件变化的生长反应可以被量化，我们对北极高山生态系统对气候变化脆弱性的了解将会增加。

Alpine ecosystems are regarded as vulnerable to climate change. Species evolved under specific harsh conditions might lose their competitive ability under warming conditions, resulting in range shifts in the species distribution, structural alterations of alpine ecosystems, and in certain areas, ultimately, a replacement of species currently growing in the upper alpine belts with those from the lower alpine belts. Retrospective growth analyses support predictions of the fate of alpine ecosystems under future global warming. In the upper alpine belts woody dwarf shrubs species form the backbone of the ecosystem. As trees, such shrubs form annual growth rings, and in recent years dendroecology of (dwarf) shrubs has emerged as a new and promising scientific field. Here, we aim to analyze the timing of growth of, climate-growth interactions in, and competition between two species, one deciduous and one evergreen, as example of a characteristic low alpine ridge site in the Norwegian Scandes. This will be done through the construction of ring-width chronologies (one for each species) and the statistical comparison of these growth time-series with both a unique, long-term, site specific, micro-climatic record and the regional climate record. By studying the species response to past and ongoing climate variability through retrospective growth analyses, the susceptibility of the species to their local climate envelope and the influence of climate variability on their competition will be revealed. This way, their future growth response to modified climatic site conditions can be quantified and our understanding of the vulnerability of arctic-alpine ecosystems to climate change will increase.