基于LUCC的陕西渭北旱塬区景观生态风险评价  

Landscape ecological risk assessment in Weibei dryland region of Shaanxi Province based on LUCC

作　　者：尉芳 刘京 夏利恒 龙小翠 徐仲炜 WEI Fang;LIU Jing;XIA Li-heng;LONG Xiao-cui;XU Zhong-wei(College of Natural Resources and Environment,Northwest A&F University,Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China,Ministry of Agriculture,Yangling 712100,China)

机构地区：[1]西北农林科技大学资源环境学院,农业部西北植物营养与农业环境重点实验室,陕西杨凌712100

出　　处：《中国环境科学》2022年第4期1963-1974,共12页China Environmental Science

基　　金：国家自然科学基金资助项目(42071240);中央高校基本科研业务费资助项目(2452018143)。

摘　　要：基于土地利用/土地覆被变化构建景观生态风险评价模型,评价了渭北旱塬区1980~2018年的生态风险状况.结果表明,随着城镇快速扩张,土地开发利用强度加大,各土地利用类型发生了不同程度的变化,其中,耕地减少量最多,共减少了636.36km^(2),建设用地增加量最大,共增加了496.17km^(2);受人口增长和退耕还林、还草政策实施等因素的影响,渭北旱塬区共有3492.40km^(2)土地发生了转化,变化比例为8.80%,耕地、林地、草地和建设用地之间的转化最明显,转化面积为3177.22km^(2),占转化总面积的90.98%;研究期间,低、中低风险区面积占比由20.23%降至19.01%,中风险区面积占比由41.62%升至43.23%,中高、高风险区面积占比由38.15%降为37.77%,生态风险等级整体表现偏高,呈现出"四周低,中间高"的分布特征,高风险区主要分布在景观较破碎的地区,这些地区容易受到人类活动的干扰.此外,研究区生态风险均值呈现先上升后下降的波动降低趋势,整体生态安全有所改善,但局部地区的生态环境质量减低;研究区5期生态风险值的全局Moran’s I指数均高于0.55,说明生态风险值在空间上呈显著的正相关性,高-高聚集区主要分布在中高、高风险区,外界活动对该区域自然生态的干扰较大,生态环境受到较为严重的破坏.This study constructed a landscape ecological risk evaluation model based on land use/land cover change and evaluates the ecological risk status of the Weibei dryland region from 1980 to 2018.The results showed that:With the rapid expansion of towns and cities and the growth of land development and utilization intensity,different land use types have changed to different degrees,among which,arable land decreased the most,with a total decrease of 636.36km^(2),while construction land increased the most,with a total increase of 496.17km^(2).Influenced by factors such as population growth and the implementation of the policy of returning farmland to forest and grass,a total of 3492.40km^(2) of land in the Weibei dryland region was converted,with a change ratio of 8.80%.The advantage of transfer between farmland,forest land,grass and construction land was most obvious,with a conversion area of 3177.22km^(2),accounting for 90.98%of the total transformed area.During the study period,the proportion of low and medium-low risk areas decreased from 20.23%to 19.01%,the proportion of medium-risk areas increased from 41.62%to 43.23%,and the proportion of medium-high and high-risk areas decreased from 38.15%to 37.77%,with an overall high ecological risk level,showing the distribution characteristics of"low around,high in the middle".In addition,the mean value of ecological risk in the study area shows a fluctuating trend of increasing and then decreasing,and the overall ecological safety has improved,but the quality of ecological environment in some areas has decreased.The global Moran's I index of the landscape ecological risk values of the five time nodes in the study area were all higher than 0.55,indicating a spatially significant positive correlation of ecological risk values.The"high-high"concentration areas are mainly located in the medium-high and high-risk areas,where the ecological environment has been more seriously damaged due to large-scale disturbance by human activities.

关 键 词：土地利用/土地覆被 生态风险评价 景观格局 渭北旱塬区 

分 类 号：X820.4[环境科学与工程—环境工程] X171.4