Stochastic assembly in a subtropical forest chronosequence: evidence from contrasting changes of species, phylogenetic and functional dissimilarity over succession.
Deterministic and stochastic processes jointly determine the community dynamics of forest succession. However, it has been widely held in previous studies that deterministic processes dominate forest succession. Furthermore, inference of mechanisms for community assembly may be misleading if based on a single axis of diversity alone. In this study, we evaluated the relative roles of deterministic and stochastic processes along a disturbance gradient by integrating species, functional, and phylogenetic beta diversity in a subtropical forest chronosequence in Southeastern China. We found a general pattern of increasing species turnover, but little-to-no change in phylogenetic and functional turnover over succession at two spatial scales. Meanwhile, the phylogenetic and functional beta diversity were not significantly different from random expectation. This result suggested a dominance of stochastic assembly, contrary to the general expectation that deterministic processes dominate forest succession. On the other hand, we found significant interactions of environment and disturbance and limited evidence for significant deviations of phylogenetic or functional turnover from random expectations for different size classes. This result provided weak evidence of deterministic processes over succession. Stochastic assembly of forest succession suggests that post-disturbance restoration may be largely unpredictable and difficult to control in subtropical forests.
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Xiangcheng
X
Mi
Department of Biology, University of Maryland, College Park, Maryland, 20742 USA.
Nathan G
NG
Swenson
College of Chemistry and Life Science, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
Qi
Q
Jia
College of Chemistry and Life Science, Zhejiang Normal University, Jinhua, Zhejiang 321004, China.
Mide
M
Rao
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Gang
G
Feng
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Haibao
H
Ren
Earthwatch Institute, Mayfield House, 256 Banbury Road, Oxford, OX2 7DE, United Kingdom.
Daniel P
DP
Bebber
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
Keping
K
Ma
D044822:Biodiversity; D065928:Forests; D010802:Phylogeny; D019655:Quantitative Trait, Heritable; D013045:Species Specificity; D013269:Stochastic Processes; D014329:Tropical Climate