Topography Controls the Abundance of Siberian Larch Forest
Topography Controls the Abundance of Siberian Larch Forest
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地形控制西伯利亚落叶松森林的丰度
DOI：
10.1002/2017jg004096
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Hideki KOBAYASHI
中科院分区：
文献类型：
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作者：
Hisashi SATO;Hideki KOBAYASHI
落叶松是东西伯利亚针叶林的主要组成部分，其丰度很大程度上取决于当地的水文条件，而水文条件主要受 100 m 尺度的地形特征调节。本研究评估了落叶松森林的地理异质性是如何形成的，特别关注地形及其相关的环境异质性。对落叶松为主的地区进行了主成分分析（PCA），以汇总环境变量（即地形特征、洪水风险和气候变量）之间的地理相关性。在主成分分析中，前三个主成分（PC1、PC2 和 PC3）解释了 63.6% 的环境变量地理异质性。 PC1、PC2和PC3分别与沿纬度的环境梯度、土壤持水能力和坡向密切相关。使用前三个 PC 作为自变量，计算多元回归方程来解释落叶松 LAI 的地理异质性。多元回归方程提取了落叶松 LAI 在以下环境条件下升高的趋势：(1) 纬度较低，(2) 较高的土壤持水能力直到一定阈值，(3) 朝南的坡度。洪水风险和落叶松森林存在的 2 × 2 列联表表明，落叶松森林避开了受洪水威胁的区域。这些结果表明，除了气候环境之外，地形特征还通过干旱和洪水胁迫控制东西伯利亚落叶松森林的丰度。
Larch trees are the dominant elements of coniferous forests in Eastern Siberia, and its abundance largely depends on local hydrological conditions, which are predominantly mediated by topographic properties at the 100 m scale. The present study evaluated how geographic heterogeneity of the larch forest is formed with a special focus on topography and its related environmental heterogeneity. A principal component analysis (PCA) was conducted for larch‐dominated areas to aggregate the geographic correlations among environmental variables, namely, topographic properties, flooding risk, and climatic variables. In the PCA, the first three principal components (PC1, PC2, and PC3) explained the 63.6% of geographical heterogeneity of environmental variables. PC1, PC2, and PC3 were tightly correlated with the environmental gradient along latitude, soil water holding capacity, and slope aspect, respectively. Employing these first three PCs as independent variables, a multiple regression equation was calculated to explain geographic heterogeneity of larch LAI. The multiple regression equation extracted trends that the larch LAI becomes higher for environmental conditions of (1) lower latitude, (2) higher soil water holding capacity until a certain threshold, and (3) south‐faced slope. The 2 × 2 contingency tables of inundation risks and presence of larch forest showed that larch forests avoid areas threatened by flooding. These results suggest that topographic properties, besides climatic environment, control the abundance of larch forest via both drought and flooding stresses in Eastern Siberia.