青藏高原东北边缘云-冷杉林火烧迹地灌木群落种群生态位特征

Niche Characteristics of Population in Shrub Communities in Spruce-fir Forest Burned Areas on the Northeast Margin of Qinghai-Tibetan Plateau

[目的]揭示青藏高原东北边缘云-冷杉林不同年限火烧迹地灌木群落种群生态位特征。[方法]以空间代替时间方法,采用Levins和Shannon Wiener生态位宽度指数、Pianka和Schoener生态位重叠指数计算种群生态位宽度和生态位重叠程度,并划分群落特化种和泛化种。[结果]火烧迹地和未过火林地灌木物种Levins和Shannon Wiener生态位宽度指数结果基本一致,同一物种在火烧迹地和未过火林地的生态位宽度存在差异。5 a火烧迹地有3个特化种;15 a火烧迹地有2个特化种和1个泛化种;未过火林地有1个特化种。种间生态位重叠严重的种对数占比为15 a火烧迹地>5 a火烧迹地>未过火林地;生态位重叠一般的种对数占比为5 a火烧迹地>15 a火烧迹地>未过火林地;生态位重叠较小的种对数占比为未过火林地>15 a火烧迹地>5 a火烧迹地。[结论]青藏高原东北边缘云-冷杉林经过重度火干扰后,不同年限火烧迹地灌木群落种间生态位重叠程度正在不断地发生变化,而未过火林地林下灌木层种间生态位重叠程度则保持一个相对较低的状态,火烧迹地灌木群落正处于正向演替阶段。

[Objective]To reveal the niche characteristics of shrub community population in the burned areas of Spruce-fir forest in different years on the northeast edge of Qinghai-Tibetan Plateau.[Method]Levins and Shannon Wiener niche breadth index,Pianka and Schoener niche overlap index were used to calculate the niche breadth and niche overlap degree of population,and the specialized spe-cies and generalized species of community were divided.[Result]The results of Levins and Shannon Wiener niche breadth index of shrub species in burned and unburned forest land were basically the same,and there were differences in the niche breadth of the same species in burned and unburned forest land.There are three specialized species in the 5-years burned area,two specialized species and 1 generalized species in the 15-years burned area and one specialized species in unburned forest land.The proportion of species logarithms with severe niche overlap among species was 15-year-burned land>5-year-burned land>unfired forest land.The species logarithm proportion of general niche overlap was 5-years-burned land>15-yearly-burned land>unfired Woodland.And the proportion of species logarithm with less niche overlap was unburned forest land>15 years burned area>5 years burned area.[Conclusion]After severe fire disturbance in the Spruce-fir forest on the northeast edge of Qinghai-Tibetan Plateau,the de-gree of niche overlap among species of shrub communities in burned areas of different years is constantly changing,while the degree of niche overlap among species in undergrowth of unburned forest land re-mains relatively low,and the community is in a positive succession stage.