云龙天池国家级保护区云南松种群年龄结构及动态分析

Age structure and dynamics of Pinus yunnanensis population in Yunlong Tianchi Nature Reserve

云南松是中国西南地区的特有树种。云南松林是暖温性针叶林的典型代表,主要分布于滇中高原。云南松种群是否可以自我更新,将影响滇中地区的植被动态。明晰未受干扰的云南松种群的结构和动态是研究云南松林可持续发展的重要基础。云南省云龙天池自然保护区内的云南松林是较为原始的森林。以云龙天池国家级自然保护区云南松天然种群为研究对象,分析了云南松天然种群静态生命表、存活曲线、生存函数曲线和谱分析。结果表明:云龙天池国家级自然保护区的云南松年龄结构为倒J型,种群年龄结构数量变化动态指数V_(pi)为28.29%,存在外部干扰时侯的种群年龄结构动态指数V'_(pi)为1.77%,种群动态指数V_(pi)和V'_(pi)都大于0,种群在外部环境干扰下承担的风险概率P_(max)为6.25%,以上结果表明云南松种群为增长型种群结构,具有一定的抗干扰能力。云南松种群的存活曲线为Deevey-Ⅱ型,生存分析发现生存率、累计死亡率、死亡密度和危险率在Ⅰ-Ⅶ龄级(胸径<35 cm)变化较大,Ⅶ-XVI龄级(胸径35-80 cm)趋于稳定;谱分析结果表明第Ⅲ龄级(胸径10-15 cm)是影响种群数量的主要阶段。以上结果说明云南松种群的低龄级个体数量波动大,个体死亡较多,高龄级衰退,建议自然保护区内的天然云南松幼龄林和中龄林可以采取抚育间伐措施来促进其种群的生长发育和更新。

Pinus yunnanensis is an endemic tree species in Southwest China.P.yunnanensis forest is a typical representative of warm coniferous forest,mainly distributed in the central Yunnan plateau.Whether P.yunnanensis populations can self-renew or not will affect the vegetation dynamics in central Yunnan.Clarifying the structure and dynamics of undisturbed P.yunnanensis populations is an important basis for studying the sustainable development of P.yunnanensis forests.The P.yunnanensis forest in the Yunlong Tianchi Nature Reserve in Yunnan Province is a relatively pristine forest without human interference.In this study,the static life table,survival curve,survival function curve and spectral analysis of P.yunnanensis natural populations were analyzed in Yunlong Tianchi Nature Reserve.The results demonstrated that the age structure of P.yunnanensis in Yunlong Tianchi National Nature Reserve was inverted J-type,the dynamic index of population age structure change in quantity V_(pi) was 28.29%,the dynamic index of population age structure in the presence of external disturbance V'_(pi) was 1.77%,the population dynamic index V_(pi) and V'_(pi) were both greater than 0,and the probability of the population assuming risk under external disturbance was P_(max) 6.25%.The above results indicated that the P.yunnanensis population is a growing population structure with some resistance to disturbance.Furthermore,the P.yunnanensis population had a survival curve tending to the type of Deevey-II,and the survival analysis found that the survival rate,cumulative mortality rate,mortality density and hazard rate varied greatly fromⅠtoⅦage classes(diameter at breast height<35 cm),and stabilized fromⅦto XVI age classes(diameter at breast height 35-80 cm).The spectral analysis exhibited that the population dynamics of P.yunnanensis followed one major trend,and theⅢage class(diameter at breast height 10-15 cm)was the main stage affecting the population size.The above results reveal that the number of individuals in the lower age classes of P.yunnanensis populations in the Yunlong Tianchi Nature Reserve fluctuates greatly,with more individuals dying and the upper age classes declining.It is suggested that the young and middle-aged natural P.yunnanensis forests in the Yunlong Tianchi Nature Reserve can be nurtured and intercut to promote their population growth,development and renewal.Based on all these results,the population of P.yunnanensis was found to remain sustainable in the long term,although it fluctuates in the middle and lower ages.