生物结皮对荒漠草本植物群落结构的影响

Effect of Soil Microbiotic Crust on Plant Community in the Gurbantunggut Desert

通过人工去除生物结皮试验,分析古尔班通古特沙漠生物结皮对常见荒漠草本植物群落结构的影响。根据人为去除生物结皮的试验结果,结合生物结皮对种子萌发、幼苗存活以及土壤养分和水分等影响,综合分析生物结皮对草本植物多样性的影响。结果表明:尖喙牻牛儿苗(Erodium oxyrrhynchum)、条叶庭荠(Alyssum linifolium)、琉苞菊(Hyalea pulchella)、荒漠庭荠(Alyssum desertorum)及旱麦草(Eremopyrum triticeum)的生物量总和占总生物量的90%以上,是该沙漠的优势草本植物。去除生物结皮后,草本植物的植被高度、物种丰富度和多样性指数都显著提高;但是,植被盖度、密度和群落生物量却显著降低。说明生物结皮的存在改变了古尔班通古特沙漠南缘荒漠草本植物的群落结构,植被盖度和群落生物量提高,这对于防风固沙、稳定沙面具有重要的生态意义。

The plant communities in the microbiotic crust-intact and microbiotic crust-removed plots in the Gurbantonggut Desert were investigated. The desert is mosaics-patched by vascular plants and soil microbiotic crust.The influence of soil microbiotic crust on seed germination,seedling survival,soil nutrient content and water distribution was firstly discussed,and then the influence of soil microbiotic crust on plant diversity was studied. The results showed that the sum of the biomass of five dominant herb species including Erodium oxyrrhynchum,Alyssum linifolium,Hyalea pulchella,Alyssum desertorum and Eremopyrum triticeum contributed more than 90% of the total aboveground biomass of the synusia. Compared with the microbiotic crust-intact plot,the plant height,Shannon Wiener diversity index（H） and species richness（R） were significantly increased after the microbiotic crust was removed. However,the plant density,productivity and coverage were lower than those in microbiotic crust-intact plot. These results indicated that the diversity and coverage of herbaceous plants were significantly affected by microbiotic crust. It is concluded that microbiotic crust could promote the restoration of desert ecosystem.