J Plant Ecol ›› 2019, Vol. 12 ›› Issue (3): 438-447.DOI: 10.1093/jpe/rty027

• Research Articles • Previous Articles     Next Articles

Testing mechanisms underlying elevational patterns of lakeshore plant community assembly in Poyang Lake, China

Zhichun Lan1,2,3,4, Yasong Chen1, Lei Li1,2,4,5, Feng Li6, Binsong Jin1,2,4,5 and Jiakuan Chen2,*   

  1. 1 Jiangxi Province Key Laboratory of Watershed Ecosystem Change and Biodiversity, Center for Watershed Ecology, Institute of Life Science, School of Life Sciences, Nanchang University, Nanchang 330031, China
    2 Coastal Ecosystems Research Station of the Yangtze River Estuary, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China
    3 Key Laboratory of Watershed Ecology and Geographical Environment Monitoring, NASG, Nanchang 330029, China
    4 Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang 330031, China
    5 National Ecosystem Research Station of Jiangxi Poyang Lake Wetland, Nanchang 330038, China
    6 Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
    *Correspondence address. Coastal Ecosystems Research Station of the Yangtze River Estuary, Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, School of Life Sciences, Fudan University, Shanghai 200438, China. Tel: +86-0791-8382-7011; Fax: +86-0791-8382-7086; E-mail: jkchen@fudan.edu.cn
  • Received:2018-02-12 Revised:2018-07-17 Accepted:2018-07-18 Online:2018-10-31 Published:2019-07-01

Abstract:

Aims

Plant community assembly in wetlands usually changes with elevation gradients, which may be due to the direct effect of flooding and indirect effects such as changes in soil properties and competition. However, the respective importance of each factor remains to be investigated.

Methods

We investigated patterns of plant diversity, community biomass and soil properties along an elevation gradient of a lakeshore meadow at Poyang Lake, China.

Important Findings

(i) With increasing elevation, species richness and Simpson diversity index decreased. Both aboveground biomass (AGB) and belowground biomass (BGB) increased with elevation, however, the BGB/AGB ratio also increased, which suggests a significant effect of belowground competition. (ii) Soil N content and soil N:P ratio increased, whereas soil pH decreased with elevation. Other soil properties showed no significant response. (iii) Structural equation modeling showed that variation of plant diversity was mainly explained by BGB. Thus, intensified belowground competition seems to be the primary mechanism causing lower plant diversity at higher elevations. (iv) These findings were further supported by the observed greater response ratio of N and P storage in plant communities than the response ratio of soil N and P content to elevation, suggesting that soil nutrient limitation and belowground nutrient competition increased with elevation. Our study has important implications to wetland management and biodiversity conservation under environmental change (e.g. changes in flooding regimes, eutrophication).

Key words: belowground competition, aboveground competition, flooding tolerance, nutrient limitation, biomass allocation