小叶锦鸡儿放牧场沙漠化过程中植物多样性的变化

对科尔沁沙地小叶锦鸡儿放牧场在沙漠化过程中物种多样性的变化特征进行了研究。分析了植物种类消长规律、生活型结构变化、优势度以及生态位宽度的变化情况。物种多样性指数分析表明，沙漠化过程是一个物种多样性衰减的过程，沙漠化导致大多数原生性物种消失。固定沙丘到半固定沙丘这一过程是整个沙漠化过程中物种多样性丧失最快的阶段。从生活型来看，地面芽植物受沙漠化影响最大。采用Levins公式测度了科尔沁沙地不同沙漠化阶段中17个主要种群生态位宽度变化情况。结果表明，大多数原生植物种群的生态位宽度沙漠化进程中逐渐降低，而侵入的沙生植物则呈现了相反的变化趋势。

Plant Species Diversity Changes of Caragana Microphylla Pasture in Process of Desertification

The changing characteristics of species diversity of Caragana microphylla pasture during the process of sandy desertification in Keerqin Sandy Land were studied. The invasion and disappearance of plant species, the change of dominance and life form structure, and niche breadth of dominant populations were also analyzed, The species diversity indexes analysis showed that desertification was a process of bio-diversity loss. And most of original species were wiped out in this process especially from fixed sand dune to semi-fixed sand dune stage. Change in life-form spectra indicated that Hermicryptophytes were severe affected by desertification. The drift of niche breadths of 17 main plant populations in the process of desertification was measured using the formulas described by Levins. The results showed that the niche breadths of most original species decreased and those of psammophytic species increased accordingly in the process of desertification.