乌拉山自然保护区油松种群结构与分布格局研究

Population Structure and Distribution Pattern of Pinus tabulaeformis in Wulashan Natural Reserve of Inner Mongolia

针对乌拉山自然保护区天然油松种群的分布特点,设置了3个具有代表性的样地,采用种群径级结构代替年龄结构、点格局分析(Ripley’sK-Function)方法对油松种群年龄结构和空间分布格局进行了研究,以期为干旱半干旱地区山地森林生态系统的评价及管理提供依据。结果表明:不同样地油松种群年龄结构处在不同发育阶段,这主要是由油松自身的生物学特性、环境因素以及人为干扰共同导致的结果。整体上,该种群年龄结构呈现稳定型,且种群的存活曲线接近于DeeveyⅡ型。乌拉山天然油松种群在不同年龄结构和生境条件下呈现出不同的分布格局类型,在生长环境适宜(海拔1 400 1 800 m的阴坡、半阴坡)且种群以幼树和中龄树为主时呈集群分布;在高海拔(1 800 m以上)石质阳坡分布的油松种群年龄偏大、密度较低,种群空间分布格局以随机分布为特征。

Pine community is one of the most important community types in Wula Mountain which is a large water conservation area in western Inner Mongolia Autonomous Region.There is great significance to master the pine population structure and distribution patterns for the health assessment and management of mountain forest ecosystem in arid and semi-arid areas.By studying the distribution characteristics of natural pine（Pinus tabulaeformis Carr.） population in Wula Mountain Nature Reserve,three representative samples were set up and the age structure and spatial distribution patterns of the pine populations were studied by using the population diameter instead of the age class structure and point pattern analysis（Ripley＇s K-Function） methods.The results showed that the age structure of pine population was at different developmental stages due to pine＇s own biological characteristics,environmental factors and human interference.Overall,the age structure of pine population was at the stable type in Wula Mountain.The survival curve of natural pine populations was close to DeeveyⅡ type.In addition,the natural pine populations showed different distribution patterns under different age structure and habitat conditions.Under suitable growth environment（shady slope and semi-shady slope at altitude 1 400-1 800 m） and population were dominated by middle-aged and young trees,the population showed a cluster distribution.The population distributed at high altitude（1 800 m and above） and sunny stony slope were usually older and with lower density and the population spatial pattern was characterized by a random distribution.