古尔班通古特沙漠南部防护体系建成10a来的生境变化与植物自然定居

Habitat Change and Natural Establishment of Plants in the Southern Part of Gurbantunggut Desert,China during 10 Years since Construction of Engineering Protective System

于2000—2009年对古尔班通古特沙漠南部防护体系内的生境变化与自然定居植物进行了系统观测和研究。结果表明,草方格及人工植被相结合的综合防护体系可以有效固定重大工程扰动地表。防护体系建成初期,土壤水分条件好于原始地表,为人工林的生长和植物自然定居创造了良好条件。防护体系建成10a后,土壤理化性质得到有效改善,普遍形成了地衣结皮,但土壤水分出现了减少的趋势。在未经扰动的原始地表,总计有植物48种,其中短命植物30种。防护体系建成初期自然定居植物仅有8种,10a后多达33种,其中短命植物达到21种。定居植物多度由初期的1.4株.m-2增加到10a后的14株.m-2,其中短命植物占到自然定居植物总株数的85%,很少观测到自然定居的乔灌木。自然定居植物呈明显的差异性分布,与风向对种源的影响密切相关。随着草本植物的进入、生物结皮的形成和土壤水分的减少,人工植被的稳定性问题尚需进一步研究和探讨。

The great engineering construction in the hinterland of Gurbantunggut Desert always make strong disturbance to the ground surface.In order to protect ecosystem and control blown-sand disasters,the preventing system is set up following the destruction of ground surface.In this paper,based on field measurement of plant species and their abundance and analysis of physical and chemical characteristics of soil along the section across the protective system of the engineering,plants states on the natural dune surface were studied,and the habitat change and natural establishment of plants from 2000 to 2009 were discussed as well.The sand surface disturbed by great engineering can be stabilized by straw checker-board barrier and steady concave surface forms on the initial stages.Organic matter and fine sand began to accumulate on the surface with time.Soil water content was better than that on natural ground during the first two years.A total of 48 plant species were identified in the study area,including 1 dwarf tree,4 shrubs,13 perennial and annual herbages and 30 ephemeral plants.Herbages,especially ephemerals can entrance into the protective system naturally,their species and population increased with time.8 species and 1.4 plants\5m2 were measured in protective system in 2001,while they reached 33 species and 14 plants\5m2 in 2009.Out of total number of all invasion plants,ephemeral plants accounted over 85% while the dwarf arbor and shrubs were scarcely observed along the study profile.The number of invasion plants on the north side of the engineering system was more than that on the south side,which may be affected by the wind regime.Plant abundance near the outside of protective system was more than that near the channel,which reflected the natural processes of plants entrance in this environment.With encroachment of herb plants and biological crusts and decline of soil water,the stabilization of simple man-made vegetation need further investigated in future.