Spatial and temporal variability in the responses of Arctic terrestrial ecosystems to environmental change
Spatial and temporal variability in the responses of Arctic terrestrial ecosystems to environmental change
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北极陆地生态系统对环境变化响应的时空变化
DOI：
10.3402/polar.v18i2.6574
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发表时间：
1999
期刊：
影响因子：
1.9
通讯作者：
Clive W. Anderson
中科院分区：
文献类型：
--
作者：
T. Callaghan;M. Press;John A. Lee;D. Robinson;Clive W. Anderson
本文比较了两个截然不同的北极生态系统对气候变化模拟的响应：极地半沙漠（在斯瓦尔巴群岛）和矮灌木荒原（在瑞典北部的阿比斯库）。这些生态系统分别位于北极地区的最北端和最南端。模拟气候变化的影响是通过因子摄动实验确定的，其中生长季节的温度、养分有效性和供水被操纵。这些结果与气候年际变化对来自更广泛的极地地区的一种重要苔藓物种——水蛭草（Hylocomium splendens）生长的影响进行了比较。扰动研究表明，当前温度的年际变化和许多物种的温带耐受性可能超过预测的下一个世纪夏季平均温度的变化。北极生态系统对环境操纵的反应不同，矮灌木的健康结构受到竞争等级变化的影响，可能导致生物多样性降低，极地半沙漠受到入侵的影响，可能导致生物多样性增加。与在自然环境中观察到的温度与生长之间的正相关关系相反，在亚北极地区，锦绣蓟马对扰动表现出负响应。这种明显的差异可能是由于：(i)扰动引起的伪影，例如大气相对湿度较低；（ii）相对短期扰动研究期间的非平衡响应和/或（iii）苔藓种群的生态型变化。因此，在从扰动研究推断北极更长的时间尺度和不同的生态系统时，应谨慎行事。
This paper compares the responses of two contrasting Arctic ecosystems to climate change simulations: a polar semi-desert (in Svalbard) and a dwarf shrub heath (at Abisko, northern Sweden). These ecosystems are located close to the northern-and southernmost extremes of the Arctic region, respectively. Inmacts of simulated climatic changes were determined through factorial perturbation experiments, where growing season temperature, nutrient availability and water supply were manipulated. The results are compared with the impact of interannual variation in climate on the growth of a keystone moss species, Hylocomium splendens, from the wider circumpolar area. The perturbation studies revealed that current interannual variability in temperature and the temperate tolerance of many species may exceed predicted changes in mean summer temperature over the next century. Arctic ecosystems differed in their responses to environmental manipulations, with the structure of the dwarf shrub health being affected through shifts in competitive hierarchy, potentially leading to lower biodiversity, and the polar semi-desert being affected through invasion, potentially leading to higher diversity. H. splendens showed negative responses to perturbation at the sub-Arctic site, in contrast to the positive relationship between temperature and growth observed in the natural environment. This apparent discrepancy may result from: (i) artefacts arising from the perturbations, such as lower atmospheric relative humidity; (ii) non-equilibrium responses during the relatively short-term perturbation studies and/or (iii) ecotypic variation in the moss population. Thus, caution should be employed when extrapolating from perturbations studies to both longer time-scales and different ecosystems within the Arctic.