Journal of Resources and Ecology ›› 2016, Vol. 7 ›› Issue (4): 275-280.doi: 10.5814/j.issn.1674-764x.2016.04.006

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Density Dependence of a Dominant Species and the Effects on Community Diversity Maintainance

PENG Zongbo1, 2, *, JIANG Ying2   

  1. 1 Hainan Tropical Ocean University, Sanya 572022, China;
    2 Hainan Agricultural Reclamation Academy of Science, Haikou 570206, China
  • Received:2015-11-12 Online:2016-07-25 Published:2016-07-29
  • Contact: PENG Zongbo. E-mail:pengzongbo@163.com
  • Supported by:
    The Earmarked Fund for China Agriculture Research System; Scientific Research Foundation of Hainan Tropical Ocean University

Abstract: In order to test whether density dependence influences community diversity, a combination of manipulative experimentation and plot surveys were done using Cryptocarya concinna, a dominant species in subtropical evergreen forest. Twelve pairs of 1 m2 seedling plots were built around 12 adults, and plots were treated monthly with either a fungicide or a control. The surviving proportion of C. concinna seedlings at different stages was calculated, and an analysis was conducted on the impact of fungicide on seedling survival and species richness. Correlation between relative abundance and community evenness at different ages was analyzed using plot surveys. The results showed that fungicide treatment decreased species richness of the seedling community by promoting the recruitment of common species. Furthermore, census of a 25 m radius around adult C. concinna trees confirmed that the density of saplings increased with distance from adults. Relative abundance of C. concinna decreased with increasing age, and decreasing C. concinna dominance resulted in an increase in community evenness. To avoid the appearance of a single optimum population, the dominance of C. concinna decreased with age via density dependence, and subsequently improved community species diversity.

Key words: density-dependent, dominant species, evergreen broad-leaved forest, Janzen-Connell hypothesis, species diversity