J Plant Ecol ›› 2018, Vol. 11 ›› Issue (1): 85-91.DOI: 10.1093/jpe/rtw128

• Research Articles • Previous Articles     Next Articles

Altitudinal patterns of maximum plant height on the Tibetan Plateau

Lingfeng Mao1, Shengbin Chen2,3, Jinlong Zhang4 and Guangsheng Zhou5,*   

  1. 1 Department of Renewable Resources, University of Alberta, c/o 2-60 University Terrace, Edmonton, Alberta T6G 2H1, Canada; 2 Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, 8 Jiangwangmiao, Nanjing 210042, China; 3 College of Environment and Civil Engineering, Chengdu University of Technology, Dongsanlu, Erxianqiao, Chengdu 610059, China; 4 Flora Conservation Department, Kadoorie Farm and Botanic Garden, Lam Kam Road, Tai Po, New Territories, Hong Kong SAR, China; 5 Chinese Academy of Meteorological Sciences, 46 Zhongguancun Nandajie Street, Beijing 100081, China
  • Received:2016-04-23 Accepted:2016-11-17 Published:2018-01-18
  • Contact: Mao, Lingfeng

Abstract: Aims Several studies have shown that plant height changes along environmental gradients. However, altitudinal patterns of plant height across species are still unclear, especially in regions sensitive to climate change. As canopy height decreases dramatically near the tree line in alpine areas, we hypothesize that plant height across all species also decreases with increasing altitude, and distinct thresholds exist along this gradient.
Methods Using a large dataset of maximum plant height and elevation range (400 to 6000 m a.s.l.) of 4295 angiosperms from the regional flora of the Tibetan Plateau, we regressed plant height for every 100 m belt against elevation to explore the relationships. To identify the approximate boundaries where dramatic changes in plant height occurs for herbaceous plants, shrubs, trees, woody plants and all angiosperms, we used piecewise linear regression. Phylogenetically independent contrast was used to test the potential evolutionary influences on altitudinal patterns at the family level.
Important findings Results showed that for herbaceous plants, shrubs, trees, woody plants and all angiosperms, plant height decreases significantly as altitude increases. In addition, we found that altitude, a proxy for many environmental factors, had obvious thresholds (breakpoints) dictating patterns of plant height. The results of phylogenetically independent contrast also emphasized the importance of evolutionary history in determining the altitudinal patterns of plant height for some growth forms. Our results highlight the relative intense filtering effect of environmental factors in shaping patterns of functional traits and how this could vary for different ranges of environmental variables.

Key words: functional traits, macroecology, growth form, phylogenetically independent contrast (PIC), tree line, Tibet

摘要:
Aims Several studies have shown that plant height changes along environmental gradients. However, altitudinal patterns of plant height across species are still unclear, especially in regions sensitive to climate change. As canopy height decreases dramatically near the tree line in alpine areas, we hypothesize that plant height across all species also decreases with increasing altitude, and distinct thresholds exist along this gradient.
Methods Using a large dataset of maximum plant height and elevation range (400 to 6000 m a.s.l.) of 4295 angiosperms from the regional flora of the Tibetan Plateau, we regressed plant height for every 100 m belt against elevation to explore the relationships. To identify the approximate boundaries where dramatic changes in plant height occurs for herbaceous plants, shrubs, trees, woody plants and all angiosperms, we used piecewise linear regression. Phylogenetically independent contrast was used to test the potential evolutionary influences on altitudinal patterns at the family level.
Important findings Results showed that for herbaceous plants, shrubs, trees, woody plants and all angiosperms, plant height decreases significantly as altitude increases. In addition, we found that altitude, a proxy for many environmental factors, had obvious thresholds (breakpoints) dictating patterns of plant height. The results of phylogenetically independent contrast also emphasized the importance of evolutionary history in determining the altitudinal patterns of plant height for some growth forms. Our results highlight the relative intense filtering effect of environmental factors in shaping patterns of functional traits and how this could vary for different ranges of environmental variables.