摘要
以青藏高原两种生境(阴坡和阶地)和4个斑块大小等级水平(等级1:0.2—0.6m2,G1;等级2:0.6—2 m2,G2;等级3:2—3.6 m2,G3和等级4:3.6—8.6 m2,G4)的火绒草(Leontopodium nanum)群落为对象,利用幂乘方法则,分析了其种群和群落空间异质性和群落物种多样性特征,明晰了优势种、亚优势种、伴生种和偶见种对其植被分布格局的影响。结果表明:各火绒草斑块的群落空间分布格局均呈集群分布,植物种的随机出现频率和实际出现频率的方差对数值与其幂乘方法吻合性较高(R2﹥0.8),幂乘方法能对火绒草斑块植被空间分布格局进行客观分析。优势种火绒草和线叶嵩草(Kobresia capillifolia),亚优势种球花蒿(Artemisia smithii)和珠芽蓼(Polygonum viviparum)等的相对空间异质性(ε)高于群落的空间异质性(δC),位于直线y=0上方,使群落趋于集群分布;伴生种西北针茅(Stipa krylovii)、瑞香狼毒(Stellera chamaejasme)和苔草(Carex sp)等的ε与群落的δC类似,位于直线y=0附近,它们维持群落自身空间分布状态;偶见种的ε低于群落的δC,位于直线y=0下方,降低群落的集群分布。随火绒草斑块等级水平的增加,群落物种数呈增加,丰富度指数DGI呈降低变化。一般火绒草斑块的δc和βw为阶地﹥阴坡,DGI为阶地﹤阴坡;两种生境下,植物种组成的相似性G1斑块较低,G2—G4斑块较高。火绒草斑块的群落分布格局主要由优势种和亚优势种及偶见种的ε决定。
Under two habitats （ shady and terrace） and four grades （0.2--0.6m^2, grade 1, G1 ; 0.6--2 m^2, grade 2, （32; 2--3.6 m^2, grade 3, G3 and 3.6~8.6 m^2, grade 4, G4, respectively） of Leontopodium nanum patches in Qinghai-Tibetan Plateau, we used the power laws method ： （ 1 ） to analyze the spatial heterogeneity of populations and communities, and the species diversity characteristics of the community, （2） to determine the effects on the vegetation distribution pattern by the dominant species, subdominant species, accompanying species, and rare species. The results indicated that each L. nanum patch exhibited an aggregated distribution pattern, the variance logarithm values of both random occurrence frequency and actual occurrence frequency of each species better coincided with their respective power laws （R^2〉 0.8）, which suggested that the power laws method can objectively analyze the distribution patterns of grassland vegetation. The relative spatial heterogeneity indices （ε） of dominant species both L. nanum and Kobresia capillifolia, and subdominant species bothArtemisia smithii and Polygonum viviparum, were located in the upper y= 0, and were higher than the spatial heterogeneity index of community （δc）, which can increase the community spatial heterogeneity. For the accompanying species, including Stipa krylovii, Stellera chamaejasme, and Carex sp, their relative spatial heterogeneity indices （ε） closed the line of y = 0, and were similar with the δc of community, which can maintain the community spatial heterogeneity. While for the rare species, their relative spatial heterogeneity indices （ε） were lower than the δc of community, and were below y = 0, which can reduce the Sc of community. When the grade levels of L. nahum patches increased, the number of species in the community increased, and the richness （DGI） decreased. Generally, the δc andβw of L. nanum patches was terrace 〉 shady, and DG1 was terrace 〈 shady. The similarity of the species constitution of G1 patches was low, whereas G2--G4 patches was high. The community spatial distribution pattern of L. nanum patches is mainly determined by dominant species and rare species.
出处
《生态学报》
CAS
CSCD
北大核心
2015年第16期5306-5315,共10页
Acta Ecologica Sinica
基金
国家自然科学基金(31270558)
教育部留学回国人员45批科研启动基金
教育部"草地农业系统耦合与管理"创新团队
关键词
火绒草斑块
生境
斑块大小
幂乘方法则
分布格局
物种多样性
Leontopodium nanum patches
habitats
size of patches
power laws
distribution pattern
species diversity
