【摘要】 在对怀来盆地退耕还草过程中的3个阶段———撂荒地、草地和灌丛地植物群落样方调查的基础上,初步给出了其生态系统自然恢复中植物群落组分、群落外貌和结构、群落多样性和均匀度、群落生物量等的变化规律,分析了草地阶段在生态系统恢复中的特殊地位,进一步阐述了灌丛在该区生态系统中对草本植物具有改善其生存环境却又使其处于竞争劣势的双重作用.更多还原

【Abstract】 Field research is done in Huailai basin,a typical region on north China farming-grazing transitional zone.Based on the plant quadrat research of the three natural recovery stages of the abandoned cropland(i.e. the abandoned land stage),grassland stage and brushy land stage,the changes of floral composition,the community physiognomy and structure,Shannon-Wiener index and Alatalo evenness index and the aboveground biomass are showed.The grassland is a special stage during the ecosystem recovery process.Two paradoxical effects of the shrub on herbaceous plants are discussed.It could provide better living conditions for the herbaceous plants and make them in inferior position in competitions.更多还原