Journal of Plant Ecology ›› 2020, Vol. 13 ›› Issue (3): 281-287.DOI: 10.1093/jpe/rtaa012

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  • 收稿日期:2019-11-12 修回日期:2020-02-25 接受日期:2020-03-20 出版日期:2020-06-01 发布日期:2020-03-21

Soil nitrogen availability intensifies negative density-dependent effects in a subtropical forest

Fengmin Huang, Minxia Liang, Yi Zheng, Xubing Liu, Yuxin Chen, Wenbin Li, Shan Luo and Shixiao Yu*   

  1. Department of Ecology, School of Life Sciences/State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, China

    *Corresponding author. E-mail:
  • Received:2019-11-12 Revised:2020-02-25 Accepted:2020-03-20 Online:2020-06-01 Published:2020-03-21



关键词: 密度制约, 根系损伤, 土壤可利用氮, 土壤病原菌, 亚热带森林



The importance of density-dependent mortality in maintaining tree species diversity is widely accepted. However, density-dependent effects may vary in magnitude and direction with different abiotic conditions in forests. Theoretical predictions surmise that density-dependent effects may vary with soil available nitrogen (AN), but this still needs to be tested.


We analyzed the density-dependent effects on survival of newly germinated seedlings for 18 common species based on a long-term seedling census across environmental gradients in a subtropical forest. We also conducted a root lesion detection experiment for five species to investigate the potential effects of pathogens on variation in density-dependent disease between rich and poor AN environments.

Important Findings

The seedling dynamics analysis revealed that the strength of density-dependent effects increased with AN, shifting from neutral or positive with low AN to negative with high AN. Three of the five tree species had stronger density-dependent effects on root lesions in rich AN environments than in poor AN environments, which is consistent with the results of a long-term seedling dynamics analysis. We also found higher species diversity in rich AN environments, which may be promoted by the stronger negative density-dependent effects. Both the seedling dynamic analysis and root lesion detection experiment revealed stronger negative density-dependent effects in higher AN environment, resulting from stronger disease pressure by soil pathogens. Our study emphasized the importance of considering context dependence when testing the density dependence hypotheses.

Key words: density dependence, root lesions, soil available nitrogen, soil pathogen, subtropical forest