浙江清凉峰台湾水青冈种群2006-2011年更新动态及其与生境的关系

Topography related regeneration dynamics of Fagus hayata during 2006-2011 at Qingliangfeng Nature Reserve in Zhejiang Province

关键词:  台湾水青冈  清凉峰国家级自然保护区  冗余分析  生命表  种群动态

Key words:  Fagus hayatae  Zhejiang Qingliangfeng National Nature Reserve  RDA  static life table  population dynamics

摘要:

台湾水青冈为我国特有的国家II级重点保护野生植物,被IUCN定为渐危种,其为建群种的群落更是罕见。浙江清凉峰国家级自然保护区有较大面积的台湾水青冈群落,为了解该保护区台湾水青冈种群的更新特点及影响其生长的生境因子,在保护区内建立了1 hm²台湾水青冈群落动态样地,于2006年和2011年对胸径≥1 cm的个体进行每木定位调查和复查。基于调查数据,对台湾水青冈种群的结构、补员和死亡情况进行了比较分析,并编制了台湾水青冈种群特定时间生命表,绘制其死亡率曲线和消失率曲线,同时利用冗余分析(RDA)法分析了影响台湾水青冈更新的主要生境因子。结果表明:(1)5年间样地内台湾水青冈个体从448株增长到468株,增幅为4.3%;(2)水青冈种群径级多度分布呈反“J”形,显示种群结构稳定;(3)死亡率和消失率曲线变化趋势基本一致,分别在第Ⅳ龄级、第Ⅴ龄级、Ⅸ龄级出现3个峰值;(4)4个地形因子(海拔、凹凸度、坡度和坡向)均对台湾水青冈的生长有明显的影响。

Abstract:

Fagus hayatae is one of the second class nationally protected plants in China. It is listed by IUCN as an endangered species. Moreover,plant community dominated by F. hayatae is scarce. To explore the regeneration dynamics of F. hayata in Qingliangfeng National Nature Reserve in Zhejiang,we established 1 hm² dynamic plot in 2006,all woody plants with DBH(diameter at breast height)≥1 cm in the plot were tagged,mapped,measured and identified. Based on data from censuses between 2006 and 2011,the DBH structures and rates of mortality and recruitment were analysed. We built a static life table,and compiled the mortality rate and disappearing curve of F. hayata. Also,we analysed the environmental factors' effects on the growth rates and DBH structure of F. hayata using redundancy analysis(RDA). The results were as follows:(1)A total of 20 stems were recruited and the population size increased by 4.3% in five years;(2)The size class abundances structure represented a reverse J shape,indicating a stable population structure;(3)The mortality rate curve and disappearing curve had similar shape,both with local peaks at the 4^th,6^th and 10^th age classes;(4)The growth of F. hayata was mostly affected by convexity and slope,while less influenced by elevation and aspect.Fagus hayatae is one of the second class nationally protected plants in China. It is listed by IUCN as an endangered species. Moreover,plant community dominated by F. hayatae is scarce. To explore the regeneration dynamics of F. hayata in Qingliangfeng National Nature Reserve in Zhejiang,we established 1 hm² dynamic plot in 2006,all woody plants with DBH(diameter at breast height)≥1 cm in the plot were tagged,mapped,measured and identified. Based on data from censuses between 2006 and 2011,the DBH structures and rates of mortality and recruitment were analysed. We built a static life table,and compiled the mortality rate and disappearing curve of F. hayata. Also,we analysed the environmental factors' effects on the growth rates and DBH structure of F. hayata using redundancy analysis(RDA). The results were as follows:(1)A total of 20 stems were recruited and the population size increased by 4.3% in five years;(2)The size class abundances structure represented a reverse J shape,indicating a stable population structure;(3)The mortality rate curve and disappearing curve had similar shape,both with local peaks at the 4^th,6^th and 10^th age classes;(4)The growth of F. hayata was mostly affected by convexity and slope,while less influenced by elevation and aspect.