Long-Term Ecosystem Effects of Sand-Binding Vegetation in the Tengger Desert, Northern China

摘要

The planting of sand-binding vegetation in the Shapotou region at the southeastern edge of the Tengger Desert began in 1956. Over the past 46 years, it has not only insured the smooth operation of the Baotou-Lanzhou railway in the sand dune section but has also played an important role in the restoration of the local eco-environment; therefore, it is viewed as a successful model for desertification control and ecological restoration along the transport line in the arid desert region of China. Long-term monitoring and focused research show that within 4-5 years of establishment of sand-binding vegetation, the physical surface structure of the sand dunes stabilized, and inorganic soil crusts formed by atmospheric dust gradually turned into microbiotic crusts. Among the organisms comprising these crusts are cryptogams such as desert algae and mosses. In the 46 years since establishing sand-binding vegetation, some 24 algal species occurred in the crusts. However, only five moss species were identified, which was fewer than the species number in the crust of naturally fixed sand dunes. Other results of the planting were that near-surface wind velocity in the 46-year-old vegetation area was reduced by 54.2% compared with that in the moving sand area; soil organic matter increased from 0.06% in moving sand dunes to 1.34% in the 46-year-old vegetation area; the main nutrients N, P, K, etc., in the desert ecosystem increased; soil physicochemical properties improved; and soil-forming processes occurred in the dune surface layer. Overall, establishment of sand-binding vegetation significantly impacted soil water cycles, creating favorable conditions for colonization by many herbaceous species. These herbaceous species, in turn, facilitated the colonization and persistence of birds, insects, soil animals, and desert animals. Forty-six years later, some 28 bird species and 50 insect species were identified in the vegetated dune field. Thus, establishment of a relatively simple community of sand-binding species led to the transformation of the relatively barren dune environment into a desert ecosystem with complex structure, composition, and function. This restoration effort shows the potential for short-term manipulation of environmental variables (i.e., plant cover via artificial vegetation establishment) to begin the long-term process of ecological restoration, particularly in arid climates, and demonstrates several techniques that can be used to scientifically monitor progress in large-scale restoration projects.