巴丹吉林沙漠南缘近流沙区白刺灌丛沙堆形态特征与空间分布

白刺灌丛沙堆是风沙塑造的荒漠景观,研究白刺灌丛沙堆形态特征和分布格局对沙源的响应,可为进一步研究其形成演化提供依据。研究通过野外调查测定,对巴丹吉林沙漠南缘近流沙区白刺灌丛沙堆集中分布区的沙堆形态特征及其空间分布进行了研究。结果表明:雏形阶段和发育阶段的沙堆分别占沙堆总数的24.0%和42.2%。该区域相邻沙堆平均间距仅为9.8 m,沿主导风向,相邻沙堆的间距呈现由大快速减小,维持小间距一段距离后,再缓慢增大的分布格局,密度变化与此相反。受高沙源供给及由此带来的强蚀积转换的影响,白刺灌丛沙堆稳定化进程减缓,各项形态特征值均较小。相关性分析表明,白刺灌丛沙堆的高度、长轴长、短轴长、迎风坡长、背风坡长和底面积间均呈显著相关(P0.01)。研究结果说明,在丰富沙源供给条件下,研究区白刺灌丛沙堆处于发育的中早期阶段,在景观上表现出密度大而体型小的特点。

Morphological Characteristics and Spatial Distribution of Nitraria tangutorum Nebkhas Near Shifting Sand of Southern Margin of Badain Jaran Desert

Nitratia tangutorum nebkhas is a desert landscape which was shaped by aeolian sand. Study on response of morphological characteristics and distribution of Nitraria tangutorum nebkhas to sand supply can provide a basis for further study of its formation and evolution. This study was conducted at an area where had a massive Nitratia tangutorum nebkhas at the southern margin of the Badain Jaran Desert. The morphological characteristics and distribution pattern of the nebkhas were investigated and analyzed. The results showed that the nebkhas in early stage and developmental stage accounted for 24.0% and 42.2%, respectively, of the total nebkhas. The mean distance between adjacent nebkhas was only 9.8 m. Along prevailing wind direction, the distances between adjacent nebkhas changed rapidly from big to small, keeping it for a distance and then enlarged slowly. The densities changed conversely. Under the influence of high sand supply and resulted strong soil erosion and deposition transformation, the stabilization process of Nitraria tangutorum Nebkhas was slowed down, the parameters of all the morphological characteristics were small. Correlation analysis showed that there were significant correlations between nebkhas height, length, width, windward slope length, leeward slope length, and basal area (P < 0.01). The results indicate that under the abundant supply of sand, the Nitratia tangutorum nebkhas in this area were in its early and middle stage of the whole growth phase, and showed big density with small shape landscape traits.