喀斯特季节性雨林蚬木种群的增长模型

Growth models of Excentrodendron hsienmu population in a karst seasonal rain forest

关键词:  蚬木  种群增长  模型  喀斯特季节性雨林

Key words:  Excentrodendron hsienmu  population growth  model  karst seasonal rain forest

摘要:

蚬木是喀斯特季节性雨林的优势种和特征种,研究蚬木种群的增长过程将为深入理解喀斯特季节性雨林动态提供基础。根据一个15 hm²固定样地的调查数据,采用logistic模型及其4种改进模型对蚬木种群的增长过程进行了拟合,用残差平方和、决定系数和AIC准则对拟合的模型进行评价。结果表明:李新运模型和刘金福模型的拟合效果较好,但综合考虑模型的拟合效果和模型的简洁性,logistic模型和S形增长过程模型为较优模型。用logistic模型对蚬木种群的增长过程进行深入分析发现,种群增长最快的时期为50 a左右,而在150 a后,种群逐渐进入增长饱和期。种群目前接近增长饱和期,所以应加强保护,以维持蚬木群落的稳定发展。

Abstract:

Excentrodendron hsienmu is a dominant as well as a character species of karst seasonal rain forest. Studying on growth process of E. hsienmu population may provide key insights for successional dynamics and status of the karst seasonal rain forest. Population growth dynamics of E. hsienmu was simulated by using the logistic model and 4 modified models according to the data from a 15 hm² plot of the karst seasonal rain forest at Nonggang,south China. To determine fitting goodness of the models,residual sum of squares,correlative coefficient and Akaike Information Criterion were compared. The results showed that the fitting goodness of Li Xin-Yun model and Liu Jin-Fu modified model were the relatively better among the five models. However,the logistic model and the S-shaped growth process model were the optimal models as comparing the AIC value. Applying the logistic model,we were able to evaluate the population expansion process of E. hsienmu. The increasing rate of E. hsienmu population reached the highest peak at about 50 a,while it levelled off after 150 a. Growth of E. hsienmu population was currently close to saturation period,and enhanced protection actions were consequently needed to maintain steady development of its community.