围栏封育对退化灌丛草地群落土壤特性和植被的影响

以雅鲁藏布江中游半干旱河谷山地灌丛草地群落为研究对象,采用野外调查和室内试验结合的方法,研究了围栏封育对灌丛草地植被及土壤养分含量的影响,以期为有效修复雅鲁藏布江中游河谷山地植被退化提供科学参考。结果表明:围栏封育3年土壤有机质、全磷、速效磷、速效钾含量均高于围栏外,土壤表层(0～10cm)养分含量增加显著(P<0.05),随着土壤深度的增加,土壤养分含量与围栏外逐渐趋于一致,至30～40cm到达相同水平;围栏封育后灌丛草地群落高度和产量显著增加(P<0.05),分别比围栏外增加了74%和101%,高度、产量增加主要是由禾本科和莎草科引起;围栏封育对群落组成和物种重要值产生不同程度的影响,主要表现为生物多样性增加,禾本科、莎草科等适口性好的物种重要值增加,杂草类不可食物种重要值相对下降;Rarefaction曲线法结果显示,围栏内物种多样性大于围栏外,与传统多样性指数方法结果一致。

Influences of Fencing on Soil Properties and Vegetation in Degraded Shrub-grass Community

The shrub-grass communities in the semiarid Yarlung Zangbo River valley were used as the research object,the effects of enclosure on vegetation and soil porperties of shrub-grass communities were studied by field investigation and laboratory experiments.In order to provide reference for the restoration and treatment of mountainous vegetation degeneration.The results showed that the contents of soil organic matter,total phosphorus,available phosphorus,and available potassium in the fence were obviously increased after three years compared with the outside the fence,and their differences in soil layer of 0-10 cm in depth were significant(P<0.05).With the increase of soil depth,the soil nutrient contents were gradually consistent with outside the fence,reaching the same level at 30-40 cm.The shrub-grass vegetation height and biomass of the fenced were obviously increased(P<0.05),with an increase rate of 74% and 101% respectively,due especially to the increase of the height and biomass of Poaceae and Cyperaceae plants.The community composition structure and important values of plant species were changed by the fence,indicating that the fence increased plant diversity and the important value of palatable Poaceae and Cyperaceae plants and decreased the important values of some unpalatable weedy plants.The results of rarefaction curve showed that the species diversity inside the fence was higher than outside the fence,which was consistent with the result of traditional diversity index method.