地处腾格里沙漠东南缘的沙坡头人工固沙植被始建于1956年,46 a来不仅确保了包兰铁路沙漠地段的畅通无阻,而且对区域生态环境的恢复产生了巨大的影响,成为我国干旱沙漠地区交通干线荒漠化防治与生态恢复的成功模式.长期定位监测结果表明:人工固沙植被建立4～5 a后,沙丘表面物理结构初步得到稳定,并由大气降尘形成的无机土壤结皮逐渐演变形成土壤微生物结皮.荒漠藻类、苔藓和地衣等隐花植物在结皮层中得到了大量的繁衍:固沙植被建立46 a后出现藻类24种;苔藓仅有5种,少于天然固定沙丘结皮上的种类,此外,地衣也在植被区发现,这说明固定沙丘景观逐渐趋于稳定的状态;相对于流沙区,固沙植被区近地面风速降低了40%,土壤有机质含量增加了60%,其中氮、磷、钾等荒漠生态系统主要限制养分因子及土壤理化性质得到了改善,沙丘表层成土过程明显;土壤水分循环的时空变异驱动了植被的演变,为大量的草本的侵入和定居创造了条件;此外,对鸟类、昆虫和土壤动物及荒漠动物的生存产生了积极的影响.46 a后,固沙植被区共有鸟类28种,昆虫50种,动物23种.生物多样性的恢复使原有的相对单一的固沙植被演变成一个结构、组成和功能相对复杂的荒漠生态系统.沙坡头地区生态环境在人为促进下的恢复为我国西部生态建设提供了科学依据.
Sand-binding vegetation in Shapotou region at southeastern edge of Tengger Desert began to be planted in 1956. Over the past 46 years it not only ensured the smooth operation of the Baotou-Lanzhou railway in the sand dune section, but also played an important role in the restoration of local eco-environment and therefore it is viewed as a successful model for the desertification control and ecological restoration along the transport line in the arid desert region of China. Long-term monitoring and located research show that 4~5 years after the establishment of sand-binding vegetation, surface physical structure of sand dunes initially became stable, and inorganic soil crusts formed by atmospheric dust gradually turned into microbiotic crusts. Among the organisms comprising the crusts are cryptograms such as desert algae and mosses etc. Over 46 years after establishing sand-binding vegetation, some 24 algal species occurred in the crusts, but only 5 moss species were identified, this is fewer than the species number in the crust of naturally fixed sand dunes. Near-surface wind velocity in 46-year-old vegetation area reduced by 54\^2% compared to that in the moving sand area, soil organic matter increased from 0\^06% in moving sand dunes to 1\^34% of 46-year-old vegetation area, main nutrients N, P, K etc, in the desert ecosystem increased, soil physiochemical properties improved, soil-forming processes occurred in dune surface layer; the variations of soil water cycle in time and space drove the evolution of vegetation and created favorable conditions for the invasion of many herbaceous species. This also produced active effects on the existence of birds, insects, soil animals and desert animals. 46 years later, some 28 birds species, 50 insect species and 23 animal species were identified in the vegetated dune field. The restoration of biodiversity led to the transformation of the relatively single primary sand-binding vegetation into desert ecosystem with complex structure, composition and function. The restorat
Journal of Desert Research