题目：Plantation age, understory vegetation, and species-specific traits of target seedlings alter the competition and facilitation role of Eucalyptus in South China.
作者：Zhongyu Sun1，Yuhui Huang2，Long Yang1,3 ， Val Schaefer4，Yanqiao Chen1
单位：1.Guangdong Open Laboratory of Geospatial Information Technology and Application, Guangzhou Institute of Geography, Guangzhou, China；2.Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou, China；3.Address correspondence to L. Yang, email email@example.com 4.School of Environmental Studies, Faculty of Social Sciences, University of Victoria, Victoria, BC, Canada
摘要：The Chinese government is considering ways to reconstruct Eucalyptus plantation monocultures in order to improve their ecosystem services. However, the effects of competition or facilitation of Eucalyptus on native species during the reconstruction have not been identified, especially during the formation of novel ecosystems. To better understand these relationships, in this study we tested the effects of competition and facilitation of Eucalyptus on three target species (Schima superba, Michelia macclurei, and Castanopsis fissa), in Eucalyptus plantations with different ages and understory vegetation. The results showed that the survival and growth of S. superba and M. macclurei were not sensitive to plantation age and understory removal treatment. The survival of C. fissa in understory removal was significantly higher and the growth of C. fissa increased gradually with increasing plantation age. The relative neighbor effect (RNE) index for growth indicated that the relationship between Eucalyptus and target species switched from competition to facilitation with an increase in plantation age. A redundancy analysis (RDA) showed that survival was positively correlated with soil water content and soil phosphorus. Growth was positively correlated with soil organic matter and soil nitrogen and negatively correlated with soil bulk density. Our results indicate that plantation age, understory vegetation, and species-specific traits of target seedlings could change the competition and facilitation roles of Eucalyptus. Higher survival and growth rates indicated that C. fissa was an appropriate species for the reconstruction of mature Eucalyptus plantations and understory removal will benefit the process.
关键词：biotic and abiotic factors, Eucalyptus plantation, monoculture reconstruction, relative neighbor effect, seedling fitness, tree-seedling interaction