关键词: 科尔沁沙地, 土地利用变化, CLUE-S模型, 情景分析

Abstract: Horqin desert and its surrounding area(41°17'～45°24' N,116°21'～123°30' E),loca-ted in the eastern part of agro-pas ture transitional zone in northern China,is an area sensitive to environmental change due to transitional location and the high potential for sandy desert-if ication.During the past decades,the rapid expansion of sandy desertification i n this area has greatly accelerated the processes of environmental change,leadi ng to deterioration of the eco-environmental conditions in northern China.Land-use and land-cover change is the center of the interests of the science of gl obal environmental change,and thus has aroused increasing attention of scientis ts worldwide.Based on the understanding to land use dynamics between1985and 2000,land use patterns in2000,and land use planning data for2010, a model,CLUE-S,was implemented for modeling land use change in the Horqin Des ert and its surrounding area.With the help of this CLUE-S model,two scenario s of land use change,one was based on Markov process and the other on land use planning of the government,were explored for the period from₂000to2010 .Then,major land use changes were identified for each scenario by overlaying e ach simulated land use map of2010with land use map of2000.Some of the implications of each scenario were analyzed and presented in this paper.The mai n conclusions of the study are drawn as follows.Common land use changes in the period between2000and2010according to the two scenarios will take place along the line which starts from the central part of Jarud Banner turning south westwards,through Ar Horqin Banner,Bairin Left Banner,Bairin Right Banner, Linxi county till the eastern part of Hexigten Banner,then turning southwards t hrough the western part of Chifeng city and ending in the western part of Harqin Banner.The main types of potential land use change include the conversion from grassland to forestland,from cultivated land to forestland and from cultivated land to grassland.Apart from these results that are sim ilar to both scenarios,each scenario also has its own characteristics on land u se change from₂000to2010.According to the Markov scenario,conversion f rom grassland to cultivated land will occur a-long the line from the southern part of Bairin Right Banner turning southwards through the east-ern part of Ch ifeng city and Harqin Banner till the eastern part of Ningcheng county.This ind i-cates that if land use change from1985to2000can be viewed as a Markov process and the changing trend will continue in the following10years,it is m ostly likely that some grassland on both sides of the above line will be cultiv ated.In addition,the same conversion will also occur in some local areas in the central and eastern parts of the study area.Furthermore,the cultivation o f grassland may be a potential disturbance to local en vironment and great atte ntion should be tak-en to by government.According to the scenario representing planned changes,three major land use changes:from un-sed land to forestland ,from cultivated land to forestland and from unused land to grassland,will tak e place in central and eastern parts of the study area.This shows that it will be necessary to plant trees or grass in some seriously degraded areas of Horq in Desert to complete the planned task of land use.It is difficult to implement this engineering project of revegetation from the view point of ecology.The study suggests that the land-use planning from1997to2010should be discu ssed again due to lack of ecological considerations.

Key words: Horqin Desert, l and use change, CLUE-S model, scenario analysis