青藏高原东缘主要次生林物种多样性与功能多样性随海拔梯度的变化

Effects of Altitude Gradient on Community and Functional Diversity of Secondary Forest in Eastern Qinghai-Xizang Plateau

通过对青藏高原东缘甘肃南部白龙江主要次生林的研究,对物种多样性指数和功能多样性指数进行单因素方差分析和Pearson相关性分析。结果表明:(1)物种α多样性指数(SW)和优势度指数(SN)呈双峰正相关,随海拔的升高先增大后减小最后增大;丰富度指数(S)和均匀度指数(R)呈单峰负相关,丰富度指数(S)表现为先增大后减小,均匀度指数(R)表现为先减小后增大;优势度指数(SN)与均匀度、丰富度指数(S)呈显著性正相关(P<0.05)。(2)β多样性指数表现出相邻海拔区间β多样性指数较大的趋势,海拔区间相差越大β指数越小。(3)功能均匀度指数(FE_(ve))和功能分歧度指数(FD_(iv))随着海拔呈多峰变化,表现出随着海拔的升高先减小后增加然后减小,最后升高;功能丰富度指数(FR_(ic))表现为随海拔的升高先增大后减小然后增大。(4)群落中物种α多样性指数和功能多样性指数呈现复杂的相关性,优势度指数(SN)与均匀度指数(FE_(ve))呈显著正相关,优势度指数(SN)与丰富度指数(R)、多样性指数(SW)与功能分歧度指数(FD_(iv))以及功能均匀度指数(FE_(ve))与功能丰富度指数(FR_(ic))呈显著负相关,其他指数之间相关性均不显著。

Diversity-ecosystem functioning relationships can be greatly varied along the environmental gradients in plant community.Taking the secondary forest in Eastern Qinghai-Xizang Plateauthe as the research object,this study aims to investigate the species composition and structural properties of plants at the various altitude gradient.The results show that:(1)Species alpha diversity index(SW)and dominance index(SN)first increased,then decreased and finally increased with the altitude.The richness index(S)often appeared to increased first and then decreased.The opposite trend was found in the uniformity index(R)and the richness index(S).Among them,the uniformity index(R)decreased first and then increased.(2)The higher values were observed in theβdiversity index at the interval of adjacent altitude.The larger the difference in the altitude interval was,the smaller theβindex was.(3)The functional uniformity(FE_(ve))index and functional divergence(FD_(iv))index show that the multi-peaks were varied with the altitude,indicating the first decrease,increase,then decrease and final increase;The function richness(FR_(ic))index increased,then decreased,and finally increased,as the altitude increased.(4)A complex correlation was found in the speciesαand functional diversity indexes in the community.The dominance index(SN)and the uniformity index(FE_(ve))shared the significant positive correlation.The significantly negative correlation was found that between the dominance index(SN)and the richness index(R),the diversity index(SW)and the functional disparity index(FD_(iv)),as well as the functional uniformity index(FE_(ve))and the functional richness index(FR_(ic)).There was no significant correlation between the rest indexes.