荒漠草原带沙源及灌丛对灌丛沙堆形态的影响

灌丛沙堆是干旱区一种典型的景观类型,经常出现在靠近流沙地带。在地处荒漠草原带的宁夏盐池北部的流沙边缘就发育有典型的白刺(Nitraria tangutorum)灌丛沙堆。本文对不同沙源距离和灌丛生长状况下的白刺灌丛沙堆形态特征进行了研究。结果表明:荒漠草原带白刺灌丛沙堆的高度0.2～4.8 m,90.05%的高度小于3.0 m;体积0.11～805.17 m³,6.08%的体积小于150 m³;面积0.86～333.3 m²,72.26%的小于50 m²。灌丛沙堆长轴长和短轴长、高度和面积、高度和体积、面积和体积间都存在很好的幂函数关系,随着灌丛沙堆高度的增加,其面积和体积也增加。沙源对白刺灌丛沙堆的分布特征有显著影响,灌丛沙堆的高度、面积和体积和沙源距离都有很好的抛物线形关系。白刺灌丛的生长状况对灌丛沙堆的形态特征也有明显的影响,即白刺灌丛生长状况越好,灌丛沙堆的高度、面积和体积也增大。

Effect of Sand Source and Shrub Features on Nebkha Morphological Characteristics in Desert Steppe

Nebkha is a typical landscape in arid and semi-arid land, which commonly distributed in the quicksand regions. There are lots of Nitraria tangutorum nebkhas in the quicksand edge of north YanChi country under the desert steppes. This paper studied the effects of sand source and N. tangutorum growth condition on nebkhas morphology characteristics. The results are as follows: the height of N. tangutorum nebkhas in desert steppes were between 0.2-4.8 m, and about 90.05% of them were smaller than 3.0 m; the volume were between 0.11-805.17 m and only about 6.08% of them were bigger than 150 m³; the area were between 0.86-333.3 m², and about 72.26% of them were under 50 m². The relationships of long axis and short axis, height and area, height and volume, area and volume can well described with power functions. Area and volume of nebkhas were increased with the increase of nebkhas height. The distance of sand sources significantly affect the distribution characteristics of nebkhas. The growth conditions of N. tangutorum also affect the morphology characteristics of nebkhs, and the heights, areas, volumes of nebkhas were increased with the increase of coverage of N. tangutorum.