Lin Yong Chong, Xu Li Shuai
Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
Qira Field National Station of Observation & Research for Desert-grass Land Ecosystem in Xinjiang, Qira 848300, Xinjiang, China.
Ying Yong Sheng Tai Xue Bao. 2017 Apr 18;28(4):1337-1343. doi: 10.13287/j.1001-9332.201704.032.
In order to understand the environmental influence of oasis-desert ecotone to oasis ecological system, we comparatively analyzed the grain size characteristics of various aeolian sediments, including the sediments in oasis-desert ecotone, shelterbelt and the inside oasis and in Qira River valley. The results showed that the grain size characteristics (including grain-size distribution curve, grain size parameters, and content of different size classes) of sediments in the oasis-desert ecotone were consistent along the prevailing wind direction with a grain-size range of 0.3-200 μm and modal size of 67 μm. All of the sediments were good sorting and mainly composed of suspension components and saltation components, but not denatured saltation and creeping components (>200 μm). They were typically aeolian deposits being short-range transported. The grain sizes of sediments in oasis-desert ecotone were smaller than that in the material sources of Qira River valley and desert (0.3-800 μm), but very similar to those of the modern aeolian deposits in oasis-desert ecotone, shelterbelt and the inside oasis. The denatured saltation and creep components (>200 μm) were suppressed to transport into oasis-desert ecotone because of the high vegetation cover in oasis-desert ecotone. Therefore, like the shelterbelts, the oasis-desert ecotone could also block the invasion of desert. They safeguarded the oasis ecological environment together.
为了解绿洲—荒漠交错带对绿洲生态系统的环境影响，我们对比分析了包括绿洲—荒漠交错带、防护林带、绿洲内部以及策勒河谷地在内的各类风成沉积物的粒度特征。结果表明，绿洲—荒漠交错带沉积物的粒度特征（包括粒度分布曲线、粒度参数以及不同粒级含量）沿主风向具有一致性，粒度范围为0.3—200μm，众数粒径为67μm。所有沉积物分选良好，主要由悬移组分和跃移组分组成，而非变性跃移和蠕动组分（>200μm）。它们是典型的短距离搬运的风成沉积物。绿洲—荒漠交错带沉积物的粒度小于策勒河谷地和沙漠物源（0.3—800μm）的粒度，但与绿洲—荒漠交错带、防护林带和绿洲内部的现代风成沉积物粒度非常相似。由于绿洲—荒漠交错带植被覆盖率高，变性跃移和蠕动组分（>200μm）被抑制进入绿洲—荒漠交错带。因此，与防护林带一样，绿洲—荒漠交错带也能阻挡沙漠入侵。它们共同维护着绿洲生态环境。
