西藏冷杉原始林林隙对草本植物和灌木树种多样性的影响

研究了西藏东南部亚高山原始冷杉林林隙对草本植物和灌木树种多样性的影响．结果表明，西藏东南部亚高山原始冷杉林林隙与非林隙林分内草本植物和灌木树种的种类组成、数量、密度和物种多样性均存在较大的差异．由于林隙内光照条件的改善，草本植物和灌木树种更加丰富；林隙内有喜光的草本植物和灌木，也有耐荫性较强的草本植物和灌木，而非林隙林分内仅有耐荫和较耐荫的草本植物和灌木；大部分林隙内的草本植物和灌木树种的物种多样性和均匀度大于非林隙林分；林隙内与非林隙林分的群落相似系数较小，表明林隙与非林隙林分草本植物和灌木群落组成存在差异．林隙大小在174．2～562．2m^2之间，群落相似系数与林隙大小无明显关联．林隙促进了草本植物和灌木树种的繁衍，在维持藏东南亚高山原始冷杉林的物种多样性方面起着重要作用．

Effects of gap in primitive subalpine fir forest on diversity of herd and shrub in tibet

Effects of gap in primitive fir forest in southeast Tibet on species diversity of herb and shrub were studied. The results showed that species composition, distribution and diversity in gap were different from those in non-gap. The improvement of illumination and other habitat conditions resulted in richer species of herb and shrub in gap. There were shade-tolerant and photophilic herb species and shrub species in gap, however, only shade-tolerant herb species and shrub species grew in non-gap. Species diversity and evenness in gap were higher than in non-gap. The diminutive similar coefficient between herb and shrub communities showed that certain difference existed between herb and shrub communities in stands of gap and non-gap. The similar coefficients were little correlative between gap area and communities. Gap was important to improve growth of herb and shrub and maintain species diversity of primitive subalpine fir forest in southwest Tibet.