Extreme-duration drought impacts on soil CO 2 efflux are regulated by plant species composition

No Thumbnail Available
File version
Author(s)
Zhou, C
Biederman, JA
Zhang, H
Li, L
Cui, X
Kuzyakov, Y
Hao, Y
Wang, Y
Griffith University Author(s)
Primary Supervisor
Other Supervisors
Editor(s)
Date
2019
Size
File type(s)
Location
License
Abstract

Aims: Long-duration drought can alter ecosystem plant species composition with subsequent effects on carbon cycling. We conducted a rainfall manipulation field experiment to address the question: how does drought-induced vegetation change, specifically shrub encroachment into grasslands, regulate impacts of subsequent drought on soil CO2 efflux (Rs) and its components (autotrophic and heterotrophic, Ra and Rh)?

Methods: We conducted a two-year experiment in Inner Mongolia plateau, China, using constructed steppe communities including graminoids, shrubs and their mixture (graminoid + shrub) to test the effects of extreme-duration drought (60-yr return time) on Rs, Rh and Ra.

Results: Our results indicated that extreme-duration drought reduced net primary production, with subsequent effects on Rs, Rh and Ra in all three vegetation communities. There was a larger relative decline in Ra (35–54%) than Rs (30–37%) and Rh (28–35%). Interestingly, we found Rs in graminoids is higher than in shrubs under extreme drought. Meanwhile, Rh declines were largest in the shrub community. Although Ra and Rh both decreased rapidly during drought treatment, Rh recovered quickly after the drought, while Ra did not, limiting the Rs recovery.

Conclusions: This study suggests that plant species composition regulates several aspects of soil CO2 efflux response to climate extremes. This regulation may be limited by above- and below-ground net primary production depending on soil water availability. The results of this experiment address a critical knowledge gap in the relationship between soil respiration and plant species composition. With shrub encroachment into grasslands, total soil respiration is reduced and can partly offset the effect of reduction in productivity under drought stress.

Journal Title

Plant and Soil

Conference Title
Book Title
Edition
Volume

439

Issue

1-Feb

Thesis Type
Degree Program
School
Publisher link
Patent number
Funder(s)
Grant identifier(s)
Rights Statement
Rights Statement
Item Access Status
Note
Access the data
Related item(s)
Subject

Environmental sciences

Biological sciences

Agricultural, veterinary and food sciences

Persistent link to this record
Citation
Collections