物种多样性和系统发育多样性对阔叶红松林生产力的影响

生物多样性与生态系统功能间的关系已成为生态学研究的热点问题之一,其中植物多样性对森林生产力的驱动作用受到广泛关注,而其潜在驱动机制还存在很大争议.本研究依托黑龙江凉水国家级自然保护区典型阔叶红松林9 hm^2森林动态监测样地,利用2005年和2015年的调查数据,采用线性回归和结构方程模型探究不同空间尺度下物种多样性和系统发育多样性对森林生产力的影响.结果表明:物种多样性和系统发育多样性与生产力均呈正相关,随着空间尺度的增大,物种多样性对生产力的作用强度逐渐增强,而系统发育多样性对生产力的作用逐渐减弱;小尺度下系统发育多样性对生产力的影响大于物种多样性.生产力还受到非生物因素影响,在不同尺度下土壤因子与生产力均呈显著正相关,并且随着尺度的增大,土壤因子对生产力的作用逐渐占据主导地位.在今后研究中应将进化信息与生态系统功能相联系,可为其他多样性度量提供额外的解释力,同时还应考虑空间尺度及非生物因素的影响,为深入了解森林生产力的驱动机制提供科学依据.

Effects of species diversity and phylogenetic diversity on productivity of a mixed broadleaved-Korean pine forest.

The relationship between biodiversity and ecosystem function is one of the hot spot in ecological research. The driving effect of plant diversity on forest productivity has been widely focused, but its underlying mechanisms are still controversial. We explored the impacts of species diversity and phylogenetic diversity on forest productivity at different spatial scales based on a 9 hm² forest dynamic monitoring plot of typical mixed broadleaved-Korean pine (Pinus koraiensis) forest in Liangshui National Nature Reserve, Heilongjiang Province, with the censuses data in 2005 and 2015, using linear regression and structural equation models. The results showed that species diversity and phylogenetic diversity were both positively correlated with productivity. The strength of species diversity on productivity gradually enhanced as spatial scales increased, while the effects of phylogenetic diversity on productivity showed opposite trend. On small scales, the effects of phylogenetic diversity on productivity was stronger than species diversity. Moreover, productivity was affected by abiotic factors. Soil factors were significantly positively correlated with productivity at different scales, which was gradually dominated as spatial scales increased. Our results indicated that evolutionary information should be considered in future ecosystem function studies, which might provide additional explanatory power for other diversity metrics. Meanwhile, the effects of spatial scales and abiotic factors should also be considered, which could provide a scientific basis for further understanding the mechanisms underlying the changes of forest productivity.