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.
Bibliographical noteFunding Information:
This study was supported by the National Key Research and Development Program of China (2016YFC0500503 and 2016YFC0500501) and by the Department of Science and Technology of Inner Mongolia Autonomous Region for studying steppe ecosystems on the Mongolian Plateau (20140409 and 201503001).
© 2021 The Author(s).
- community composition
- Mongolian Plateau
- plant functional groups
- soil properties