关键词: 茂兰, 喀斯特森林, 灌木种群, 生态位, 优势种群

Abstract:

To understand the niche characteristics of the shrubs in Karst forest,Based on investigation on the communities,the shrub populations at three sites in Maolan National Natural Reserve were taken as a research object.The niche breadth,niche similarity and niche overlap were used to analyze the niche characteristics of dominant shrub populations.The results showed that:1)niche breadths of Mallotus repandus and Nandina domestica were larger than other species with Levins (Bi) and Hurlberts (Ba) values being 0.471 9 and 0.966 0,0.466 3 and 0.926 1.2)The niche similarity among populations increased with niche breath,as shown between Mallotus repandus and Sinosideroxylon wightianum,Mallotus repandus and Nandina domestica,Nandina domestica and Sinosideroxylon wightianum,similarity values being 0.966 3、0.902 2 and 0.868 5;the demand for environmental resources had a greater similarity of the species,although the niche breadth was smaller,but its niche similarity ratio would be higher,as shown between Brassaiopsis glomerulata and Nothopanax davidii,similarity values being 0.911 3.3)Niche breadth among larger species with large niche overlap value,as shown between Mallotus repandus,Nandina domestica and Sinosideroxylon wightianum,niche overlap values were above 0.32.The study indicates that dominant shrub populations have stronger resource utilization ability in karst forest.The higher niche similarity and niche overlap of most dominant populations show that the interspecific competition is intensive and this may be caused by complexity and high heterogeneity of karst habitat.

Key words: Maolan, rarst forest, shrub population, niche, dominant population