Predominance of abiotic drivers in the relationship between species diversity and litterfall production in a tropical karst seasonal rainforest
Predominance of abiotic drivers in the relationship between species diversity and litterfall production in a tropical karst seasonal rainforest
复制标题
热带喀斯特季节性雨林物种多样性与凋落物产生关系中非生物驱动因素的主导作用
DOI：
10.1016/j.foreco.2019.117452
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发表时间：
2019-10-01
影响因子：
3.7
通讯作者：
Li, Xiankun
中科院分区：
文献类型：
--
作者：
Guo, Yili;Chen, Han Y. H.;Li, Xiankun
凋落物是生态系统净初级生产力和生态地球化学循环的主要贡献者。然而，各种非生物和生物驱动因素如何影响异质天然林凋落物生产仍有争议。我们使用结构方程模型（SEM）测试的直接和间接影响的树种多样性，树木直径的变化，林分断面积，和非生物的驱动程序（冠层暴露，海拔，坡度，凸度，方面，地形湿度指数和海拔以上的通道）在中国南方的异质性热带喀斯特季节雨林年凋落物生产。乔木物种多样性、胸径变异、林分断面积和非生物因子的结构方程解释了年凋落物量变异的43.4%。树种多样性和林分断面积对年凋落物量有正的直接影响，而林木直径变异对年凋落物量有负的直接影响。树种多样性对胸径变异和林分断面积的影响不显著。年凋落物产量和树种多样性直接下降与水的可用性，而冠层暴露正影响年凋落物产量，但不是树种多样性。我们的研究结果表明，树木物种多样性和凋落物生产之间的正相关关系并没有导致从物种多样性对冠层包装的影响，相反，它似乎是增加土壤水分供应，同时减少热带喀斯特季节雨林的树木物种多样性和年凋落物生产。
Litterfall production is a major contributor to ecosystem net primary productivity and biogeochemical cycles. However, how various abiotic and biotic drivers influence litterfall production in heterogeneous natural forests is still debated. We used structural equation models (SEM) to test the direct and indirect effects of tree species diversity, tree diameter variation, stand basal area, and abiotic drivers (canopy exposure, elevation, slope, convexity, aspect, topographic wetness index and altitude above channel) on annual litterfall production in a heterogeneous tropical karst seasonal rainforest in Southern China. The SEM with tree species diversity, tree diameter variation, stand basal area, and abiotic drivers accounted for 43.4% of the variation in annual litterfall production. Tree species diversity and stand basal area had positive direct effects, while tree diameter variation had a negative direct effect on annual litterfall production. Tree species diversity had no significant effect on tree diameter variation nor stand basal area. Both annual litterfall production and tree species diversity decreased directly with water availability, while canopy exposure positively affected annual litterfall production but not tree species diversity. Our results indicate that the positive relationship between tree species diversity and litterfall production did not result from the effects of species diversity on canopy packing; instead, it appears that increasing soil water availability simultaneously reduce tree species diversity and annual litterfall production in the tropical karst seasonal rainforest.