Nabe-Nielsen Jacob, Normand Signe, Hui Francis K C, Stewart Lærke, Bay Christian, Nabe-Nielsen Louise I, Schmidt Niels Martin
Department of Bioscience Aarhus University Roskilde Denmark.
Arctic Research Centre (ARC) Aarhus University Aarhus C Denmark.
Ecol Evol. 2017 Oct 25;7(23):10233-10242. doi: 10.1002/ece3.3496. eCollection 2017 Dec.
Arctic plant communities are altered by climate changes. The magnitude of these alterations depends on whether species distributions are determined by macroclimatic conditions, by factors related to local topography, or by biotic interactions. Our current understanding of the relative importance of these conditions is limited due to the scarcity of studies, especially in the High Arctic. We investigated variations in vascular plant community composition and species richness based on 288 plots distributed on three sites along a coast-inland gradient in Northeast Greenland using a stratified random design. We used an information theoretic approach to determine whether variations in species richness were best explained by macroclimate, by factors related to local topography (including soil water) or by plant-plant interactions. Latent variable models were used to explain patterns in plant community composition. Species richness was mainly determined by variations in soil water content, which explained 35% of the variation, and to a minor degree by other variables related to topography. Species richness was not directly related to macroclimate. Latent variable models showed that 23.0% of the variation in community composition was explained by variables related to topography, while distance to the inland ice explained an additional 6.4 %. This indicates that some species are associated with environmental conditions found in only some parts of the coast-inland gradient. Inclusion of macroclimatic variation increased the model's explanatory power by 4.2%. Our results suggest that the main impact of climate changes in the High Arctic will be mediated by their influence on local soil water conditions. Increasing temperatures are likely to cause higher evaporation rates and alter the distribution of late-melting snow patches. This will have little impact on landscape-scale diversity if plants are able to redistribute locally to remain in areas with sufficient soil water.
北极植物群落因气候变化而改变。这些变化的程度取决于物种分布是由宏观气候条件、与当地地形相关的因素还是生物相互作用决定的。由于研究匮乏，尤其是在北极地区，我们目前对这些条件相对重要性的理解有限。我们采用分层随机设计，基于分布在格陵兰东北部沿海 - 内陆梯度三个地点的288个样地，研究了维管植物群落组成和物种丰富度的变化。我们使用信息论方法来确定物种丰富度的变化是否最好由宏观气候、与当地地形（包括土壤水分）相关的因素或植物 - 植物相互作用来解释。使用潜在变量模型来解释植物群落组成的模式。物种丰富度主要由土壤水分含量的变化决定，其解释了35%的变化，在较小程度上由与地形相关的其他变量决定。物种丰富度与宏观气候没有直接关系。潜在变量模型表明，群落组成变化的23.0%由与地形相关的变量解释，而到内陆冰的距离又额外解释了6.4%。这表明一些物种与仅在沿海 - 内陆梯度某些部分发现的环境条件相关。纳入宏观气候变化使模型的解释力提高了4.2%。我们的结果表明，北极地区气候变化的主要影响将通过其对当地土壤水分条件的影响来介导。气温升高可能导致更高的蒸发率，并改变晚融雪斑块的分布。如果植物能够在当地重新分布以留在土壤水分充足的地区，这对景观尺度的多样性影响不大。
