Aboveground and belowground competition affect seedling performance and allometry in a tropical monsoon forest
- 263 Downloads
Distinguishing the relative effects of above- and belowground competition can improve our understanding of the forces shaping community assembly in different ecosystems. In this study, we investigated the impacts of above- and belowground competition on seedling growth and allometry in a tropical monsoon forest (TMF) on Hainan Island, China. Four common dominant canopy tree species from three forest types (Schima superba in secondary forest, Peltophorum tonkinense and Vatica mangachapoi in lowland rainforest, and Terminalia nigrovenulosa in TMF) were planted in different treatments (understory vegetation removal and trenching to decrease above- and belowground competition, respectively). Three species had greater relative growth rates in height in the vegetation removal, but not in the trenching treatment. Vegetation removal reduced mortality rates for all species and increased biomass in three of the four. Trenching alone did not affect biomass for any species. Vegetation removal affected seedling allometry, resulting in higher leaf mass fraction in the lowland rainforest species P. tonkinense and V. mangachapoi. The secondary forest species, S. superba, did not successfully establish in plots with intact understory because of aboveground competition. The highly drought-adapted traits of T. nigrovenulosa allowed its seedlings to establish successfully in TMF, where it is a canopy dominant. Our results demonstrate that aboveground competition is more important than belowground competition in structuring seedling communities in TMF, because light availability largely limits seedling establishment in this ecosystem.
KeywordsBiomass Mortality Seedling growth Soil fertility Tropical forest
We thank Mr. Xiusen Yang, Jinqiang Wang, and Rucai Li for their assistance in field work. This research was financially supported by the National Natural Science Foundation of China (30901143) and by a grant from the Institute of Forest Ecology, Environment, and Protection, Chinese Academy of Forestry (CAFRIFEEP201103).
- Fang J, Wang Z, Tang Z (eds) (2009) Atlas of woody plants in China: distribution and climate. Higher Education Press, BeijingGoogle Scholar
- Forestry Institute of Guangdong Province (1964) The main economic trees of Hainan. Agriculture Press, BeijingGoogle Scholar
- Jones FA, Erickson DL, Bernal MA, Bermingham E, Kress WJ, Herre EA, Muller-Landau HC, Turner BL (2011) The roots of diversity: below ground species richness and rooting distributions in a tropical forest revealed by DNA barcodes and inverse modeling. PLoS ONE 6:e24506CrossRefPubMedPubMedCentralGoogle Scholar
- Liu W (2009) Community ecology of tropical monsoon forest in Hainan Island, China. PhD dissertation. Chinese Academy of Forestry, BeijingGoogle Scholar
- Poorter L (2005) Resource capture and use by tropical forest tree seedlings and their consequences for competition. In: Burslem DFRP, Pinard MA, Hartley SE (eds) Biotic interactions in the tropics: their role in the maintenance of species diversity. Cambridge University Press, New York, pp 35–64CrossRefGoogle Scholar
- R Core Team (2015) R: a language and environment for statistical computing. R Foundation for Statistical Computing, ViennaGoogle Scholar
- Zang R-G, Ding Y, Zhang Z-D, Deng F-Y, Mao P-L (2010) Ecological base of conservation and restoration for the major functional groups in tropical natural forests on Hainan Island. Science Press, BeijingGoogle Scholar