不同恢复措施对宁夏黄土丘陵区典型草原植物群落特征的影响

研究封育、鱼鳞坑和水平沟措施实施5a后宁夏黄土丘陵区典型草原的植物群落特征。通过野外测定,发现水平沟和鱼鳞坑措施下群落物种数较封育草地增加,但1a生物种及杂类草的重要值上升,而一些饲用价值较好的牧草重要值降低。鱼鳞坑植被盖度最高,封育草地最低,地上生物量为封育草地最高,水平沟最低。鱼鳞坑和水平沟群落的相似性较高,但均与封育草地植被有一定差异。物种Pielou均匀度指数和Shan-non-Wiener多样性指数均表现为鱼鳞坑最高,水平沟居中,封育草地最低,生态优势度则相反。说明,水平沟和鱼鳞坑整地5a后植被仍处于恢复阶段,3种措施下植物群落均处于不稳定的演替阶段,其中,鱼鳞坑措施下植物群落的稳定性最大,水平沟和封育草地的群落稳定性接近。

Influence of Different Restoration Measures on Phytocoenose Characteristics of Typical Steppe in Hilly Area of the Loess Plateau in Ningxia

The phytocoenose characteristics of typical steppe under restoration measures carried for five years including ungrazed steppe, fish scale pits and parallel ditches in hilly area of the Loess Plateau in Ningxia were studied. The results showed that the number of plant species under fish scale pits and parallel ditches were richer than ungrazed steppe. Important values of annual and forbs increased while some good feeding value pasturage decreased under fish scale pits and parallel ditches. The biggest vegetation coverage was detected in fish scale pits and the smallest was in ungrazed steppe. The biggest aboveground biomass was in ungrazed steppe and the smallest was parallel ditches. Similarity coefficient of communities between fish scale pits and parallel ditches was higher, but lower with ungrazed steppe. The descending orders of species uniformity indexand diversity indexwere fish scale pits, parallel ditches and ungrazed steppe, but ecological dominance just was adverse orders. Vegetation was recovering under fish scale pits and parallel ditches which had been carried for five years. Plant communities were in the unstable stage of succession under three measures. Relative stability of plant communities was biggest in fish scale pits, and stability was close between parallel ditches and ungrazed steppe.