摘要
额济纳绿洲是我国西北干旱区中心的一道生态防线。20世纪后半叶绿洲生态系统严重受损,景观结构急剧恶化,黑河的供水量逐年下降,由50年代的12.25×108m3下降到90年代的7.24×108m3。地下水位也相应降低,土地盐化也在加剧。各种禾草草甸严重退化,并多已演替成为苦豆子群落。为了维护我国西北的这一生态屏障,论文认为必须坚持以恢复与保护自然绿洲为主,恢复胡杨林、沙枣林、红柳灌丛与梭梭林的覆盖率;建立人工草地,改善土地覆盖,建设自然—人工复合绿洲。在绿洲建设与保育工程中必须保证供水,保持地下水位的临界高度,调控水盐动态,发挥生物—景观多样性的系统耦合效应,实现绿洲生态系统健康与资源—环境安全。
Heihe River system,originating from Qilian Mountains,is one of the important inland rivers in Northwest China.From Qilian Mountains in the south to Gobialtai mountain in the north,the Heihe drainage basin forms a mountain-basin complex in the inland arid area.The oasis belt distributed in the basin was developed with soil and water material resources from the mountains.Ejina oasis,located in the central part of the arid Northwest China,serves as an important ecological defense of the entire region.In the latter half of the20th century,the ecological sys-tem of the oasis was severely damaged,the original landscape structure was dramatically de-stroyed,the water supply from Heihe River was decreasing year by year,from1.225billion m 3 a year in the1950s to0.724billion m 3 a year in the1990s.The level of groundwater table was lowed and the land salinization were aggravated accordingly.The area of Populus euphratica and Elaeagnus angustifolia woods were decreased from34.5thousand ha to22thousand ha dominated with virgin forest.The scrubs of Tamarix ramosissima were decreased by50per cent,becoming the sparse and short community.The serious degrada-tion of herb meadows led to succession to Sophora alopecuroides community.In order to conserve the important ecological barrier of Northwest China,the main objective is to restore and conserve the natural oasis,increase the coverage of Populus euphratica woods,Elaeagnus angustifolia woods,Tamarix ramosissima scrub and Haloxylon ammodendron brush woods.Meanwhile,it is necessary to develop artificial grassland to improve the land coverage,and to construct the artificial-natural oasis.Water supply must be guaranteed for the conserva-tion and the restoration of the oasis.More attention should be paid to keep the groundwater at a suitable level,control the water-salt dynamics,and enhance the coupling effect of the bio-land-scape diversity.Thus,the ecosystem health and resource-environment safety of oasis can be com-pleted.
出处
《自然资源学报》
CSSCI
CSCD
北大核心
2002年第3期286-293,共8页
Journal of Natural Resources
基金
国家自然科学基金重点项目(39630250
39730100)资助。
