巴丹吉林沙漠高大沙山区植被特征与地貌形态的关系

通过对巴丹吉林沙漠伊和吉格德湖高大沙山区野外植被考察,研究了该地区的生物多样性,并分析了该地区植被-沙山地貌形态之间的关系。结果表明,研究区植被种类较少,以旱生物种为主,植被群落分布的垂直特征及差异明显。该区植物种共计6科9属9种,沿沙山上部至底部依次为:草本群落-灌木群落-草本或半灌木群落。沙多分布在背风坡,碟果虫实及白莎蒿多分布在迎风坡。总体群落多样性测度结果,沙山两坡中部多样性指数高,背风坡上部及迎风坡中部均匀度指数高。分层次群落多样性测度结果,由于草本种类单一,草本群落多样性及均匀度指数差别不大,迎风坡中部灌木群落多样性指数最高。高大沙山植被群落特征受整体沙山地貌形态影响,迎风坡植被分布及多样性变化特征与沙山第1和第2序列地貌形态有良好的对应关系。在更为广泛的沙漠发育时期,沙山表面稀疏的植被通过影响输沙率进而拦截沙粒,在维持沙山高度方面具有更为重要作用。

Relationship Between Vegetation Feature and Physiognomy Morphology of Mega-dunes in Badain Jaran Desert

Based on the field vegetation investigation of Yihejigede Lake in the Badain Jaran Desert, biodiversity was studied, and the relationship between vegetation and mega-dune morphology was analyzed. The results showed that there were less vegetation types in the study area, mainly composed by xeromorphic species, the vertical distribution and differences of vegetation communities was obvious. Vegetation in the study area belongs to 9 species, 9 genera and 6 families, from the top to the bottom of mega-dunes vegetation communities changed from herbaceous community to shrub communities to herb or subshrub community. Agriophyllum squarrosum distributed in the leeward slope, but Corispermum patelliforme and Artemisia blepharolepis distribuled in windward slope; The overall community diversity showed that diversity index was higher in the middle of both mega-dune slopes, and evenness index was higher in the top of leeward slope and the middle of windward slope. The hierarchical community diversity showed that diversity index and evenness index had little difference for herb community because of the relatively single species, the shrub community in the middle of windward slope had the maximum diversity index. The feature of vegetation communities was affected by the whole morphology of mega-dunes, there existed a well corresponding relation between the vegetation characteristics including distribution and diversity in the windward slope and the physiognomy morphology with order 1 and order 2 of mega-dunes. In a broader development period of desert, the sparse vegetation may play an important role in maintaining the height of mega-dunes through influencing sand transport rate and then intercepting the sand.