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喀斯特季节性雨林蚬木种群结构和数量动态

向悟生1,王斌1,丁涛1,黄俞淞1,农重刚2,刘晟源2,李先琨1**   

  1. (1广西壮族自治区中国科学院广西植物研究所, 广西桂林 541006; 2广西弄岗国家级自然保护区管理局, 广西崇左 532400)
  • 出版日期:2013-04-10 发布日期:2013-04-10

Age structure and quantitative dynamics of Excentrodendron hsienmu population in a karst seasonal rain forest in South China. 

XIANG Wu-sheng1, WANG bin1, DING Tao1, HUANG Yu-song1, NONG Chong-gang2, LIU Sheng-yuan2, LI Xian-kun1**   

  1. (1Guangxi Institute of Botany, Chinese Academy of Sciences, Guilin 541006, Guangxi, China; 2Longgang National Natural Reserve Administration of Guangxi, Chongzhou 532400, China)
  • Online:2013-04-10 Published:2013-04-10

摘要:

蚬木是喀斯特季节性雨林的特征种。为了了解蚬木种群的结构和生存状态,根据一个15 hm2固定样地的调查数据,采用数量分析方法研究了蚬木种群的年龄结构和数量动态特征。结果表明,蚬木种群的幼龄个体数量很多,年龄结构呈倒-J型;存活曲线可以同时被DeevyⅡ和DeevyⅢ型曲线拟合,但更倾向于DeevyⅡ型曲线;特定时间生命表分析结果表明,种群的死亡率在年龄级0~9 a、60~69 a出现明显的峰值;生存分析结果显示,蚬木种群生存状态具有前期波动、中期稳定、后期衰退的特点;谱分析结果表明,蚬木种群动态未发现有明显的大周期波动,但存在一个长度为11 a左右的小周期波动。综上研究结果,研究区内的蚬木种群为增长型种群结构;在不同发育阶段,蚬木种群的生存状态存在波动,在种群发育的前期和后期生存状态不稳定;蚬木种群的年龄结构和数量动态可能受本身生物学特性、负密度制约效应、喀斯特地质性干旱等因素的影响较大。
 

关键词: 可燃物, 热重分析, 燃烧性, 易燃性, 剧烈性, 持续性

Abstract: Excentrodendron hsienmu is a characteristic species in karst seasonal rain forest, and thus, to study the age structure and survival status of E. hsienmu population can provide insight into the succession process and status of karst seasonal rain forest. Based on the investigation data from a 15 hm2 plot in a karst seasonal rain forest at Nonggang of South China, and by using quantitative analysis method, this paper studied the age structure and quantitative dynamics of E. hsienmu population in the forest. In the forest, E. hsienmu population was characterized by the abundance of young individuals, and the age structure of the population was in an inverseJ shape. The survival curve of the population could be described by the Deevy Ⅱ curve and Deevy Ⅲ curve, but more appropriately by Deevy Ⅱ curve, which implied that E. hsienmu reproduced a large number of offspring to maintain its population. There existed two peak phases of mortality rate in the population lifespan, i.e., 0-9 and 60-69 years. The survivability of the population had the characteristics of fluctuated at young age, stable at middle age, and decline at old age. The quantitative dynamics of the population had no obvious large cycle fluctuation, but a small cycle (about 11 years) fluctuation. In conclusion, the E. hsienmu population in the karst seasonal rain forest was of an expanding structure, and the survival status of the population fluctuated across different life stages, with a relatively high mortality rate at young and mature stages. The age structure and quantitative dynamics of the population could be greatly affected by the biological characteristics of the population itself and by the restrictive effect of negative density as well as the karst geological drought.

Key words: fuel, thermogravimetric analysis, flammability, combustibility, sustainability., ignitibility