Environmental filtering of species with different functional traits into plant assemblages across a tropical coniferous-broadleaved forest ecotone
Background and aims
Ecotones between coniferous and broadleaved forests in tropical regions are poorly understood. Our aim was to understand community assembly across the ecotones by integrating changes in both plant functional traits and environmental factors.
The coniferous, ecotone, and broadleaved zones along each of the 15 investigation transects were discerned and surveyed. We measured eight functional traits of 174 woody species and 10 environmental factors along transects across the ecotones. We assessed between-site differences by using ANOVA, and correlations between functional traits and the environmental factors by RDA ordination.
With the variation of vegetation zones from coniferous through the ecotone to broadleaved, the functional traits of plants at the community level changed in accordance with the changes in soil and light regimes. The low soil nutrients and low soil water in the coniferous zone were the major constraints for most lowland rain forest species with acquisitive traits, while high soil nutrients, high soil water and low light in the broadleaved zone had strong filtering effects on the conifer and tropical monsoon rainforest species with conservative traits.
The soil and light conditions were the major determinants for the functional community structure of the vegetation types across the tropical coniferous and broadleaved forest ecotone.
KeywordsPlant functional traits Ecotone Tropical coniferous forest Tropical lowland rain forest Tropical monsoon rainforest Environmental factors
Coniferous forest zone
The ecotone zone
Broadleaved forest zone
Specific leaf area
Leaf dry matter content
Leaf total chlorophyll content
Leaf nitrogen concentration per mass
Leaf phosphorus concentration per mass
Leaf potassium concentration per mass
Maximum plant height
Soil water content
Soil organic matter content
Total nitrogen content
Total phosphorus content
Total potassium content
Available nitrogen content
Available phosphorus content
Available potassium content
We are grateful to the many people who have contributed to this study, especially Mr. Xiusen Yang and Mr. Rucai Li in the Bawangling National Nature Reserve for their assistance of specimen identification and field investigation work. We thank the two anonymous referees for their constructive comments, which have greatly improved the earlier version of this paper. This study was funded by the national forestry research project for public welfare (201304308).
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