Plant Diversity ›› 2021, Vol. 43 ›› Issue (06): 433-443.DOI: 10.1016/j.pld.2021.04.006

• Articles •     Next Articles

Different environmental factors drive tree species diversity along elevation gradients in three climatic zones in Yunnan, southern China

Xiaoyang Songa,b, Min Caoa, Jieqiong Lia, Roger L. Kitchingc, Akihiro Nakamuraa, Melinda J. Laidlawd, Yong Tanga, Zhenhua Suna, Wenfu Zhanga, Jie Yanga   

  1. a CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, 666303, Yunnan, China;
    b Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla, 666303, China;
    c School of Environmental&Natural Sciences, Griffith University, Nathan QLD, 4111, Brisbane, Australia;
    d Department of Environment and Science, Queensland Herbarium, Toowong, Australia
  • Received:2020-10-19 Revised:2021-04-20 Online:2021-12-25 Published:2022-01-11
  • Contact: Min Cao
  • Supported by:
    This research was supported by the National Natural Science Foundation of China (31800353 and 32061123003), the West Light Foundation of the Chinese Academy of Sciences, the Applied Fundamental Research Foundation of Yunnan Province (2019FB038, 2014GA003 and 2013FB079), the National Key Basic Research Program of China (2014CB954100) and the QueenslandeChinese Academy of Sciences Biotechnology Fund (GJHZ1130). We are grateful for the field assistance from Xishuangbanna Station for Tropical Rain Forest Ecosystem Studies (XSTRES), Ailaoshan Station for Subtropical Forest Ecosystem Studies (ASSTRES), Lijiang Forest Ecosystem Research Station and the Queensland Herbarium, Australia.

Abstract: Elevational patterns of tree diversity are well studied worldwide. However, few studies have examined how seedlings respond to elevational gradients and whether their responses vary across climatic zones. In this study, we established three elevational transects in tropical, subtropical and subalpine mountain forests in Yunnan Province, southern China, to examine the responses of tree species and their seedlings to elevational gradients. Within each transect, we calculated species diversity indices and composition of both adult trees and seedlings at different elevations. For both adult trees and seedlings, we found that species diversity decreased with increasing elevation in both tropical and subalpine transects. Species composition showed significant elevational separation within all three transects. Many species had specific elevational preferences, but abundant tree species that occurred at specific elevations tended to have very limited recruitment in the understory. Our results highlight that the major factors that determine elevational distributions of tree species vary across climatic zones. Specifically, we found that the contribution of air temperature to tree species composition increased from tropical to subalpine transects, whereas the contribution of soil moisture decreased across these transects.

Key words: Air temperature, Climate zones, Montane forest, Soil moisture, Seedling, Tree species distribution