摘要
近几十年来,锡林浩特市土地沙化和草场退化严重,是首都北京沙尘暴的主要沙源之一。该文从起沙角度出发,借鉴风蚀理论,建立了本区的生态安全评价指标,包括土壤粒径组成,有机质含量,植被覆盖度及水分条件。在土地利用现状图编制的基础上,按地块采集各指标数据,建立了生态安全评价数据库,并利用44个样地数据,运用模糊关联法,估算出各指标与生态安全的关联度,进而计算了各地块生态安全系数。最后,利用GIS技术,参照已知样地,运用模糊聚类法,进行全部地块生态安全等级评定,编制完成了研究区生态安全评价图。结果表明,锡林浩特市生态不安全区面积约798 39km2,较不安全区面积3340 81km2,分别占总土地面积的5 26%和22 01%,主要分布于西部、北部及最南部浑善达克沙地北缘的退化草地和沙地,以及锡林浩特市区周围的新开垦农地。生态安全区的面积约2065 81km2,占总土地面积的13 61%,主要分布在东部白音锡勒草原生态自然保护区及部分丘陵、台地区。在此基础上,依据土地利用宏观格局、生态安全以及现实性原则,进行了研究区土地利用方式的调整。
Xilinhaote City has experienced rapid development of desertification in last decades and listed as one of major sources of sandstorm to Beijing, the capital of China.Therefore, the security of ecological environment is indicated as the possibility whether the fine sand and silt is set into motion and transported or not in this paper.Based on this assumption, four indices have been chosen for assessment of ecological security, including grain size, vegetation coverage, content of organic matter, and precipitation.The method of?grey related degree analysis was introduced for assessment of ecological security.Firstly, the efficiency index of each factor affecting ecological security was determined based on 44 sample sites.After a map of land use was prepared a bulk of data on the above four indices were collected for each unit of land use types by using TM images and thematic maps, combined with field investigation and data inquiry.Using this database and GIS the coefficients of ecological security were computed for each map unit and categorized into four grades by Iterative Self-Organizing Data Analysis Technique A(ISODATA): secure, less secure, more dangerous, and dangerous and a map of ecological security assessment was compiled on a scale of 1∶250000.It is shown that totally most dangerous areas and more dangerous areas cover about 798.39km^2 and 3340.81km^2 respectively, accounting for 5.26% and 22.01% of the total area of the city.They are mostly located in degraded grassland in west and north Xilinhaote City and newly reclaimed arable land surrounding the city town.Some of dangerous areas can be recognized on north edge of Hunshandake Sand land in south part of Xilinhaote City.Afterwards, a scheme of land use adjustment was proposed by identifying three principles and different types of measurements were introduced for improvement of ecological environment, such as construction of intensive farmland, shifting of degraded farmland to grassland, improvement and closing of degraded grassland, shifting grazing and so on.The emphasis of land use adjustment is put on more dangerous and dangerous areas.Finally, the map of land use adjustment on same scale was finished.
出处
《资源科学》
CSSCI
CSCD
北大核心
2004年第2期108-114,共7页
Resources Science
基金
国家科技部防沙治沙应急项目(编号:FS2000 007)。