关键词: 植被覆盖, 生物量, 生态系统服务价值, 可持续发展, 土地利用/覆盖, 敦煌市

Abstract: Based on the land use/cover type data,yielded from interpretation of the 1987,1996 and 2007 Landsat-5 TM remote sensing images and field sampling,an empirical model was established to estimate ground biomass,and service value of the ecosystem of Dunhuang by means of sorting it into direct use value and indirect use value.Results show that among the eight land use types,farming land,urban construction land and vegetation-free land have increased in net area,while the other five decreased over the last two decades,which indicate that artificial ecosystem is expanding in area and vegetation shrinking in spatial coverage and as a result the ecosystem is degrading significantly.It was estimated that in Dunhuang the total ground biomass decreased by 170 856.52 t,or by 5.82‰ annually;and the total ecosystem value by 43 127.45 × 104 yuan,or by 5.17‰ annually.The proportion of the artificial ecosystem in the total value increased from 12.06% in 1987 to 25.91% in 2007,showing a clear rising trend,but that of the natural ecosystem dropped drastically.In the context of limited water resources,the rapid growth of the former was achieved at the cost of the latter,which suggests that human activities have significantly affected sustainable development of the region.Aiming at the present problems,we deem it essential to establish a sustainable development experimental zone by proceeding from rational allocation of resources,adjustment of industrial structure,technological progress,institutional guarantee,and so on.

Key words: vegetation cover, biomass, ecosystem service value, sustainable development, land use/cover, Dunhuang City