科尔沁沙地固定沙丘植被物种多样性对降水变化的响应

应用１９８６年到１９９２年固定沙丘样方调查数据和同期降水量资料，对科尔沁沙地物种多样性与年降水量的变化进行了分析。结果表明植物种丰富度以对降水量变化的反响比较强烈，一个干旱年份可减少固定沙丘植物种丰富度，而随后的恢复却需要３年友上的时间。物种多样性指数随降水量变化而变化，二者呈正相关。灰色关联分析表明，物种多样性指数Ｄ对降水量变化的反响来看，生长期降水量对物种多样性的影响大于年降水。在固定沙丘植被

RESPONSES OF SPECIES DIVERSITY TO PRECIPITATION CHANGE ON FIXED-DUNES OF THE NAIMAN BANNER REGION

The relationship between plant species diversity and precipitation change in fixed-dune vegetation of the Naiman Banner region was analyzed using quadrat and precipitation data. Species richness was affected by precipita tion change, with more than three years of above average rainfall required for communities to restore to pre-drought conditions following a dramatic reduction in a single drought year. Species diversity indices increased with enhanced precipitation, with the Simpson index showing considerably more response than the Shannon-Wiener index to in creased precipitation. Community evenness index change was lowest with irregular variation in precipitation. Growth period (May to September) precipitation more dramatically influenced species diversity than did total annual precipitation. Because shrub species richness doesn't vary with precipitation variation, it played a very important role in the conservation of species diversity of sandy land in the Naiman Banner region. Conversely, annual and perennial herb species richness was sensitive to precipitation change, with annual species richness being especially responsive.