清凉峰自然保护区台湾水青冈群落优势种群密度制约效应分析

以清凉峰自然保护区1 hm2台湾水青冈（Fagus hayatae）群落样地为对象，利用2006和2011年2次对胸径（DBH）≥1 cm每木的调查数据，对死亡和补员（recruit）动态进行了描述.同时，采用邻体（neighborhood）和空间分布格局分析方法对台湾水青冈群落优势种群密度制约效应进行了研究.结果表明：（1）5年间样地内木本植物个体数由8 439株减少到7 096株，其中，死亡1 430株，新增87株(DBH≥1 cm).此样地中，DBH≥1 cm的所有个体平均年死亡率和平均年新增率分别为3.71%和0.25%.（2）8个优势树种死亡个体主要集中在小径级，死亡个体的胸径显著小于存活个体的胸径.（3）不管是以种群所有个体是否存活作为因变量，还是以幼树个体是否存活作为因变量，邻体分析的结果都得到只有少数树种的存活与邻体同种基面积或个体数有显著相关性；空间分布格局分析得出8个优势树种中有6个表现出受密度制约的影响.

Density dependent effects on dominant tree survival in an Fagus hayatae community located at Qingliangfeng National Nature Reserve

Fagus hayatae is one of the Chinese National Protected Plant, Second class. It distributed partly at several places in Zhejiang Province, forming dominant plant community. To better protect Fagus hayatae community located at Qingliangfeng National Nature Reserve, a 1 hm2 dynamic plot was established in 2006. All woody plants with DBH （diameter at breast height）≥1 em were tagged, mapped, measured and identified to species. Based on the two census date in 2006 and 2011, the dynamics of tree short-term mortality and recruitment are represented. Meanwhile, neighborhood and spatial pattern analysis are applied to investigated density-dependent effects on tree survival of 8 dominant species in this plot. Results show that （1） The number of individuals with DBH≥1 cm decreased from 8 439 to 7 096, among which,1 430 were died, and 87 were recruited. The average annual mortality and recruitment rate of all species is 3.71% and 0.25 %, respectively. （2） Compared with large ones, small individuals had higher mortality, and mortality decreased as DBH increased. （3） Regardless of all individual survival or saplings survival as dependent variable, only 3 or 2 of 8 dominant tree species survival significantly correlated with neighbor conspecific basal area or abundance were found by using neighborhood analysis. By contrast, 6 of 8 dominant tree species were found to exhibit density dependent by using spatial pattern analysis.