宁夏盐池县不同荒漠化治理措施生物多样性研究

The Different Desertification Controlling Measures in Yanchi County of Ningxia Hui Autonomous Region

采用α-多样性指数即Shannon-W iener指数、S im pson指数、群落均匀度指数Jsw、生态优势度和β-多样性指数(相似性系数C j),通过对比不同荒漠化治理措施(人工封育、退耕还林、撂荒地)固定样地生物多样性变化,对宁夏盐池县草原群落进行了研究。结果表明:(1)随着撂荒年限的延长,撂荒地植物群落趋于稳定、均匀,但更新速度较慢。(2)采用人工封育措施的样地,SW和JSW多样性指数由外围(对照)、边缘、核心依次增大,经过两年封育后多样性指数排序变为边缘>核心>外围(对照),草场破坏相对严重的边缘区植被得到了很快的恢复。(3)退耕还林样地,2001年实施了退耕还林后植物恢复很快,群落向趋于复杂稳定的方向发展。群落发生了明显的演替。2002年退耕还林样地群落稳定性变差,更新速度缓慢。此外,还进一步分析了引起植物多样性变化的主要原因。

The grassland community in Yanchi county, Ningxia Hui Autonomous Region was measured by comparing the biodiversity of different fixed sample plots under the different desertification controlling measures （by converting farmland to forests, artificial fencing, and leaving land uncultivated）, using the methods of α-diversity index （including Shannon- Wiener index, Simpson index, Jsw which is community evenness indices） and β-diversity index （measured by similarity coefficients）. The results show that： （1） along with the year of leaving land uncultivated went on, plaht community in leaving land uncultivated tends to stability and evenness, but the speed of regeneration is relatively slow. （2） For the artificial fencing plots, Shannon-Wiener index and Jsw index changed from the order of the SW index and Jsw index of core area 〉of fringe area〉of unfenced area to the order of that of fringe area 〉of core area 〉of unfenced area after two years of artificial fencing, and the grassland in marginal region that was destroyed relatively seriously was restored soon. （3） For the plots converting farmland to forests, plant restoration was fast after converting farmland to forests in 2001, and the plant community tends to complication and stability. Plant communities＇ succession happened significantly. In 2002 the restoration speed of communities＇ stability in plots of converting farmland to forests is slow. In addition, the main causes of why the biodiversity in Yanchi County became better than ever is also presented.