The relationship between species richness and aboveground biomass in a primary Pinus kesiya forest of Yunnan, southwestern China.

Shuaifeng Li,Guanglong Ou,Wande Liu,Xuedong Lang,Hui Xu,Jianrong Su,Dafeng Hui

doi:10.1371/journal.pone.0191140

Abstract

The relationship between biodiversity and biomass is an essential element of the natural ecosystem functioning. Our research aims at assessing the effects of species richness on the aboveground biomass and the ecological driver of this relationship in a primary Pinus kesiya forest. We sampled 112 plots of the primary P. kesiya forests in Yunnan Province. The general linear model and the structural equation model were used to estimate relative effects of multivariate factors among aboveground biomass, species richness and the other explanatory variables, including climate moisture index, soil nutrient regime and stand age. We found a positive linear regression relationship between the species richness and aboveground biomass using ordinary least squares regressions. The species richness and soil nutrient regime had no direct significant effect on aboveground biomass. However, the climate moisture index and stand age had direct effects on aboveground biomass. The climate moisture index could be a better link to mediate the relationship between species richness and aboveground biomass. The species richness affected aboveground biomass which was mediated by the climate moisture index. Stand age had direct and indirect effects on aboveground biomass through the climate moisture index. Our results revealed that climate moisture index had a positive feedback in the relationship between species richness and aboveground biomass, which played an important role in a link between biodiversity maintenance and ecosystem functioning. Meanwhile, climate moisture index not only affected positively on aboveground biomass, but also indirectly through species richness. The information would be helpful in understanding the biodiversity-aboveground biomass relationship of a primary P. kesiya forest and for forest management.

Highlights

Biodiversity and biomass are two critical variables in the plant community ecosystem [1]
Our results revealed that climate moisture index had a positive feedback in the relationship between species richness and aboveground biomass, which played an important role in a link between biodiversity maintenance and ecosystem functioning
To evaluate the diversity-biomass relationship hypothesis in stand level of this forest type, we examined the relationships between aboveground biomass, species richness, stand age, the soil nutrient regime, and the climate moisture index in a P. kesiya primary forest using general linear models (GLMs) and structural equation models (SEMs) [11,27]

Summary

Introduction

Biodiversity and biomass are two critical variables in the plant community ecosystem [1]. Biodiversity declines have led to widespread concern about the loss of ecosystem function resulting from human disturbance including deforestation and afforestation under the background of global climate change [2]. The biodiversity-biomass relationship has become a major ecological focus worldwide over recent decades [3, 4]. The relationship between species diversity and biomass (sometimes instead of productivity) has led to more controversial conclusions: (1) biomass increased with species diversity, (2) biomass decreased with species diversity, and (3) no definite change [5, 6]. The ecologists have discovered that increasing plant diversity tends to be correlated with higher community productivity since the 1990s [8, 9]

Objectives

Methods

Results

Discussion

Conclusion