抛物线形沙丘与油蒿灌丛之间的动态关系

库布齐沙漠南缘广泛分布的油蒿灌丛与风沙相互作用后形成抛物线形沙丘,同时沙丘上的油蒿经历侵入、萌发、发育及衰亡的生命过程.2009年的地面测量及2005,2007,2010年的遥感监测数据显示:2005~2010年间,抛物线形沙丘顺风向东移的同时南北向扩展;油蒿灌丛分布于沙丘外侧坡面、两翼脊线和两翼间的平坦区,其生长及衰亡与沙丘弧顶段的东移和两翼外扩呈动态相关.抛物线形沙丘弧顶段内侧坡脚逐年东移为两翼间平坦区的油蒿提供了生长空间,导致油蒿群落以年龄、大小和盖度等差异为表征的分带性分布.两翼脊线上的油蒿灌丛捕获来沙后形成灌丛沙堆,其确保了沙丘两翼始终保持一定的高度,是维持抛物线形沙丘的关键因子之一,但随两翼缓慢外移,其相对位移至沙丘内侧坡面继而遭受风蚀直至消亡.沙丘外侧的油蒿灌丛使外侧坡面形态趋于稳定,同时沙埋作用又使弧顶段脊线处的油蒿灌丛逐渐消亡.

Dynamic relationship between parabolic dunes and Artemisia ordosica

Parabolic dunes arising from the interaction between Artemisia ordosica shrubs and aeolian activities are distributed widely in the southern part of the Hobq desert. On the dunes, the shrubs sequentially experience a process of invasion, germination, development and decline. Results of topographical investigations of a parabolic dune combined with satellite images from 2005, 2007 and 2010 show that the dune moved toward the east while its two arms expanded outward. Shrubs were distributed at the crests of b...