J Plant Ecol ›› 2021, Vol. 14 ›› Issue (4): 679-691 .DOI: 10.1093/jpe/rtab021

• Research Articles • Previous Articles     Next Articles

Plant functional groups mediate effects of climate and soil factors on species richness and community biomass in grasslands of Mongolian Plateau

Zijing Li1,2, Maowei Liang3, Zhiyong Li2, *, Pierre Mariotte4, Xuze Tong5, Jinghui Zhang2, Lei Dong6, Ying Zheng2, Wenhong Ma2, Liqing Zhao2, Lixin Wang2, Lu Wen2, Indree Tuvshintogtokh7, Elise S. Gornish8, Zhenhua Dang2, Cunzhu Liang2 and Frank Yonghong Li2   

  1. 1 Department of Grassland Science, Key Laboratory of Grassland Resources of the Ministry of Education, Key Laboratory of Forage Cultivation, Processing and High Efficient Utilization of the Ministry of Agriculture and Rural Affairs, Inner Mongolia Key Laboratory of Grassland Management and Utilization, College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010011, China, 2 Department of Ecology, Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China, 3 Department of Ecology, Institute of Ecology, College of Urban and Environmental Science, Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China, 4 Grazing Systems, Agroscope, Grazing Systems Group, Route de Duillier 50, 1260 Nyon, Switzerland, 5 Laboratory of Grassland Ecological Remote Sensing, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China, 6 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China, 7 Institute of General and Experimental Biology, Mongolian Academy of Sciences, Ulaanbaatar 51, Mongolia, 8 School of Natural Resources and the Environment, The University of Arizona, Tucson, AZ 85721, USA

    *Corresponding author. E-mail: zylee007@imu.edu.cn
  • Received:2020-05-19 Revised:2020-07-05 Accepted:2021-07-31 Online:2021-03-09 Published:2021-08-01

Abstract:

Aims

Functional group composition of a plant community is mainly driven by environmental factors and is one of the main determinants of grassland biodiversity and productivity. Therefore, it is important to understand the role of plant functional groups (PFGs) in mediating the impact of environmental conditions on ecosystem functions and biodiversity.

Methods

We measured plant biomass and species richness (SR) of grasslands in 65 sites on the Mongolian Plateau and classified 157 perennial herbaceous plants into two main PFGs (namely grasses and forbs). Using the random forest model and ordinary least squares regression, we identified that environmental factors (i.e. aridity index, soil total nitrogen [STN] and pH) were significantly related to the SR and aboveground biomass (AGB) of PFGs. We then used structural equation modeling to explore the relationship between the identified environmental factors and community SR and biomass, and the role of PFGs in driving this relationship.

Important Findings

We found that aridity index had unimodal relationships with both AGB and SR of the PFGs and the whole community. All SR and biomass metrics were significantly related to STN and pH. The relationship between aridity index and community biomass was mediated by an increase in the AGB of grasses. The influence of STN and pH on community SR was mainly due to their regulation in the SR of forbs. Our results indicate that community composition and the identity of the PFGs play a key role in linking environmental factors to ecosystem functioning.

Key words: climate, community composition, plant functional groups, Mongolian Plateau, soil properties

摘要:
植物功能群在调控气候和土壤因子对蒙古高原草原群落物种丰富度和生物量影响中的作用
植物功能群组成主要受环境因素驱动,同时植物功能群组成也是影响草地生物多样性和生产力的主要因素之一。因此,理解植物功能群在调控环境因素对生态系统功能和生物多样性影响中可能发挥的作用至关重要。通过对蒙古高原草原65个样点的植物生物量和物种丰富度的调查,将157种多年生草本植物分为两种植物功能群(即禾草和杂类草)。通过随机森林模型和普通最小二乘回归,确定与植物功能群物种丰富度和地上生物量显著相关的环境因素(即干燥度、土壤总氮和pH),并利用结构方程模型探讨筛选出的环境因素与群落物种丰富度和生物量间的关系,以及植物功能群在驱动这种关系中发挥的作用。干燥度与禾草、杂类草以及整个群落的地上生物量和物种丰富度均呈显著的单峰关系。所有的物种丰富度和生物量指标均与土壤总氮和pH值显著相关。禾草在维持蒙古高原草原生态系统群落生物量中起着关键作用,并受气候因素的直接影响。而杂类草物种丰富度决定了群落总丰富度,并受到土壤因素直接的调控。因此,群落组成在调控环境因素对群落生物量和植物多样性的影响中起着关键作用。

关键词: 气候, 群落组成, 植物功能群, 蒙古高原, 土壤性质