JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2021, Vol. 45 ›› Issue (1): 116-122.doi: 10.12302/j.issn.1000-2006.201907004

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Population structure and dynamics of the endangered plant Chieniodendron hainanense in Hainan

JIANG Xingxiang1(), CHEN Yukai1,*(), WU Shisong2, CHEN Qing3   

  1. 1. Ministry of Education Key Laboratory for Ecology of Tropical Islands, College of Life Sciences, Hainan Normal University, Haikou 571158, China
    2. Hainan Huishan Provincial Nature Reserve Administration, Qionghai 571400, China
    3. Hainan Bawangling National Nature Reserve Administration, Changjiang 572722, China
  • Received:2019-07-10 Accepted:2020-04-08 Online:2021-01-30 Published:2021-02-01
  • Contact: CHEN Yukai E-mail:1759200369@qq.com;chenyukai@hainnu.edu.cn

Abstract:

【Objective】Understanding the survival status of endangered plants and their population dynamics is of great significance for their conservation in Hainan Province, China. The present study analyzed the age structure and population dynamics of the endangered plant Chieniodendron hainanense in two habitats with different disturbance intensities, explored the relationship between the C. hainanense population and the environment, and discussed the main factors threatening C. hainanense. It aimed to provide evidence for the maintenance and restoration of C. hainanense. 【Method】 In 2018-2019, a community investigation was carried out in nine typical plots of C. hainanense in Hainan using the quadrat method. The elevation, slope, aspect, canopy density and vegetation of each plot were recorded. The height and diameter at breast height (DBH) of each C. hainanense individual were recorded both in typical and atypical communities. Based on the composition and structure of the typical communities, all the surveyed communities were assigned to habitats with either high or low levels of human disturbance. The DBH of the C. hainanense population was divided into seven diameter classes, which were used as a surrogate of its age class to examine the population structure. The size structure of the C. hainanense population was analyzed. We used the quantitative analysis to establish a static life table of the C. hainanense population, analyzing survival and mortality curves, and other important parameters. A time series model was applied to model and predict the quantitative dynamics and development trend of the C. hainanense population. 【Result】①Species diversity in the tree and shrub layers were both higher in the typical communities. ②The age structure of the C. hainanense population differed between the two habitats. The young and middle-aged individuals were somewhat prominent, suggesting the potential for restoration of the population. ③The number of seedlings in the two habitats was low, with the age class II population showing a decreasing trend. The population showed a low self-renewal capacity and was vulnerable to external disturbances. ④The population survival curve belonged to the Deevey-Ⅱtype, and was diagonally shaped, with each age class stage showing the same overall mortality. ⑤The survival ability of the C. hainanense population was lower in the high disturbance habitats than in the low disturbance habitats. 【Conclusion】 The loss of suitable habitats caused by human activities and the low natural germination rate of seeds are the two most influential factors that endanger the C. hainanense population. Therefore, the protection of existing C. hainanense adults and their suitable habitats should be strengthened. For the C. hainanense aggregated areas, it is proposed to harvest the seeds regularly during the fruit maturation period and apply artificial care to promote seed germination and seedling regeneration. It is also proposed to prune the old C. hainanense individuals appropriately to increase seed germination and flowering and fruiting rates. Finally, around the high disturbance areas, it is necessary to improve the public awareness of plant protection to minimize human disturbance. Similarly, in the low disturbance areas, artificial care should be strengthened for the medium and small-sized C. hainanense individuals to promote the natural regeneration and restoration of the C. hainanense population.

Key words: Chieniodendron hainanense, population structure, dynamic feature, survival curve, time sequence prediction, Hainan Province

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