湖北神农架地区巴山冷杉（Abies fargesii）种群结构特征与空间分布格局

巴山冷杉群落是湖北神农架地区主要的群落类型之一,从生命表特征、年龄结构、存活曲线以及种群和不同龄级个体空间分布格局等方面研究了湖北神农架地区巴山冷杉的种群结构特征与空间分布规律.研究结果表明:巴山冷杉的种群年龄结构图呈现的是幼苗比例最大,中龄树、幼树和成龄树比例次之的规律;巴山冷杉幼苗储备丰富,巴山冷杉自身的生物学特性及环境因素是形成这种现象的主要原因;湖北神农架地区巴山冷杉种群的存活曲线接近于Deevey C型,I径级巴山冷杉死亡率最高,II径级开始巴山冷杉幼树死亡率大幅度下降,直至老龄期死亡率逐渐升高;巴山冷杉种群不同年龄级的个体呈现出集群分布或随机分布,处于不同发育阶段的个体群,其空间分布格局是随时间变化的.

Structure characteristics and spatial distribution of Abies fargesii population in Shennongjia National Nature Reserve, China

Life history characteristics and spatial distribution of Abies fargesii population in Shennongjia National Nature Reserve was studied using the life table, age structure and survivorship curve of the Abies fargesii population in Shennongjia nature reserve to explain: 1) population growth characteristics, and 2) how can biological and environemental factors affect population distribution and dynamics? Abies fargesii is distributed mainly on certain attitude that ranges from 2000 m to 3104.5m in shennongjia nature reserve. We sampled trees in 30 plots(20m×20m),and,in each plot, we chose 5 grids(5m×5m) for shrubs, 10 grids(1m×1m) for grasses, and 10 grids (1m×1m) for regeneration layer. The diameter at breast height(DBH) of each tree was recorded. We determined the life table, age structure and survivorship curve of the Abies fargesii to analyze population structure and dynamics. The age structure of the population indicates that Abies fargesii population is a developing population. The survivorship curve of Abies fargesii population generally matches a Deevey Type I, although seedlings is rare and have low survival rate due to high crown density. The spatial distribution in different growth periods are clumped or random. Populations tend to clump when interspecific competition is not severe in a wet and cold habitat in shennongjia nature reserve. Intraspecific competition also affects the clustering intensity of different growth periods.