Phylogenetic constraints to soil properties determine elevational diversity gradients of forest understory vegetation
Phylogenetic constraints to soil properties determine elevational diversity gradients of forest understory vegetation
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DOI：
10.1007/s11258-017-0732-z
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发表时间：
2017-04
期刊：
影响因子：
1.7
通讯作者：
Nobuhiko Shigyo;K. Umeki;Haruka Ohashi;K. Kawada;T. Hirao
中科院分区：
文献类型：
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作者：
Nobuhiko Shigyo;K. Umeki;Haruka Ohashi;K. Kawada;T. Hirao
植被的海拔多样性梯度既受植物进化历史的影响，也受生态因子的影响。然而，很少有人关注进化制约因素的作用以及环境因素之间复杂相互作用的影响。在这里，我们研究了环境因素在森林林下植被形成EDG中的直接和间接影响。研究样地是沿着海拔梯度在日本中部东京大学七步林的寒温带和亚高山森林中选择的。在这些样地中，对树苗和草本植物进行了鉴定，并对环境因子(海拔、土壤温度、土壤pH、土壤CN比率、森林类型、断面积、冠层开度和坡度)进行了测量。采用包括分类学和系统发育多样性在内的结构方程模型来研究环境条件与林下植被多样性之间的因果关系。此外，还对栖息地要求中的系统发育信号进行了检验。乔木苗木的分类多样性和系统发育多样性随海拔的升高而单调增加，草本植物的分类多样性也表现出相同的规律。扫描电子显微镜分析表明，树苗的分类多样性和系统发育多样性受土壤性质的影响最大，而草本植物的系统发育多样性受光照条件的影响较大。这些结果突显了根据土壤性质进行环境过滤在形成树苗的EDG中的重要性。这项研究表明，在预测环境波动下EDGs的变化时，应考虑适应土壤性质的系统发育约束。
Elevational diversity gradients (EDGs) of vegetation are shaped by the evolutionary histories of plants as well as by ecological factors. However, few studies of EDGs have focused on the roles of phylogenetic constraints and the effects of complicated interactions among environmental factors. Here, we examine the direct and indirect effects of environmental factors in forming EDGs of forest understory vegetation. The study plots were selected along elevational gradients in cool-temperate and sub-alpine forests in the University of Tokyo Chichibu Forest of central Japan. Tree seedlings and herbs were identified, and environmental factors (elevation, soil temperature, soil pH, soil CN ratio, forest type, basal area, canopy openness, and slope) were measured in these plots. Structural equation modeling (SEM) including taxonomic and phylogenetic diversity was used to consider the causal relationships between environmental conditions and the diversity of understory vegetation. In addition, phylogenetic signals in habitat requirements were tested. The taxonomic and phylogenetic diversities of tree seedlings increased monotonically with elevation, and the same pattern was found for the taxonomic diversity of herbs. The SEM indicated that both the taxonomic and phylogenetic diversity of tree seedlings were most affected by soil properties, although the phylogenetic diversity of herbs was determined by light conditions. These results highlight the importance of environmental filtering by soil properties in shaping EDGs of tree seedlings. This study implies that phylogenetic constraints in the adaptation to soil properties should be considered when predicting changes in EDGs under environmental fluctuations.