天童站博士生郑丽婷在《Journal of ecology》发表论文
作者：天童站 更新时间：2019-10-11
2019年1月，华东师范大学天童站阎恩荣老师研究组在《Journal of ecology》期刊上发表题为 “Tree species diversity promotes litterfall productivity through crown complementarity in subtropical forests” 的研究论文。
论文链接：
https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13142
生物多样性与生态系统生产力的关系及其内在机制一直是生态学研究的热点和难点问题之一。生态位互补在生物多样性-生态系统生产力关系中的重要作用被广泛认可，但有关森林中树冠结构互补如何影响这种关系的研究证据非常缺乏。森林凋落物生产力与生态系统净初级生产力成正比，那么在森林中物种多样性是否通过增加树冠互补性而提高凋落物生产力呢？
本研究以中国浙江省东部28个亚热带森林群落为研究对象，调查测量了各群落的凋落物生产力、物种多样性、树冠构型、土壤含水量、土壤总有机碳含量和林龄。量化了天然林中树冠结构互补性 (图1)，利用简单线性回归，分析了树种多样性、树冠互补性、树冠体积、土壤含水量、土壤碳含量、林龄与凋落物生产力间的关系。采用结构方程模型，量化了物种多样性对凋落物生产力的直接影响，以及通过树冠互补性而产生的间接影响。结果发现，树木物种多样性通过树冠互补性，而非树冠体积增加凋落物生产力 (图4) 。物种多样性、树冠互补性、凋落物生产力均随土壤含水量提高而显著增加。树冠互补性和凋落物生产力也与土壤碳含量显著正相关。凋落物生产力随林龄而增加，但是，林龄对物种多样性和树冠互补性无显著影响（图2,图3,图4）。
综合而言，本项研究证明了树冠配置在塑造自然森林生态系统功能方面扮演着重要角色。相互作用个体间产生的树冠空间互补性是驱动亚热带森林树木物种多样性-生产力正向关系的主要生态机制之一。关注森林共存物种的树冠变异特征可极大提高我们对群落和生态系统的理解。
论文主要附图：
Figure 1 Conceptual diagram of crown complementarity (CC) calculations for a pair of trees. (a): Overview of several trees within a plot. Panel (b)-(d): three cases for calculating the crown complementarity index with respect to a focal tree i. (b) When the crowns of tree i and tree j are totally non-overlapping along the height axis, CCij=1. (c) When the crowns of tree i and tree k are partly overlapping along the height axis, 0< CCik <1. (d) When the crowns of tree i and tree m are equally overlapping along the height axis, CCim=0.
Figure 2 Bivariate relationships between endogenous (dependent) and exogenous (independent) variables (n = 28). (a)–(d) Soil moisture content (SM) vs. rarefied species richness (Srare), crown complementarity index (CCI), total crown volume (TCV), and litterfall productivity (LP), respectively. (e)–(h) Soil total organic carbon content (TOC) vs. rarefied species richness (Srare), crown complementarity index (CCI), total crown volume (TCV), and litterfall productivity (LP), respectively. (i)–(l) Stand age (SA) vs. rarefied species richness (Srare), crown complementarity (CCI), total crown volume (TCV), and litterfall productivity (LP), respectively. Coefficients of determination (Adjusted R2) and P values are shown. All numerical variables were natural log-transformed.
Figure 3 Bivariate relationships between endogenous (dependent) and exogenous (independent) variables (n = 28). (a)–(b) Rarefied species richness (Srare) vs. litterfall productivity (LP) and crown complementarity index (CCI), respectively. (c) Crown complementarity index (CCI) vs. litterfall productivity (LP). (d) Rarefied species richness (Srare) vs. total crown volume (TCV); (e) total crown volume (TCV) vs. litterfall productivity (LP). Coefficients of determination (Adjusted R2) and P values are shown. All numerical variables were natural log-transformed.
Figure 4 Structural equation models linking litterfall productivity to stand age and site condition, rarefied species richness, crown complementarity, and total crown volume. For each path, the standardized regression coefficient is shown. Black solid lines represent significant paths (P < 0.05), gray solid lines represent marginal significant paths (0.05 ≤ P < 0.1), and gray dash lines are for non-significant paths (P ≥ 0.1). R2 indicates the total variation in an endogenous (dependent) explained by all exogenous (independent) variables.
《Journal of ecology》期刊是英国生态学会主办的生态学旗舰期刊，主要刊载有关植物生态学、水生和陆生生态系统等生态学相关学科的研究，为国际著名的生态学刊物之一（IF：5.17）。
论文第一作者为我院在读博士研究生郑丽婷，通讯作者为阎恩荣教授。