摘要
西北干旱区土壤盐渍化问题突出,生态环境脆弱。土地利用类型变化分析以及景观指数评价可为区域自然环境保护、规划、管理提供依据。渭-库绿洲是南疆典型的干旱区绿洲,且土壤盐渍化问题比较突出,使用Landsat-9、Landsat-8遥感影像数据,从随机森林、支持向量机、梯度提升树、分类回归树、最小距离、朴素贝叶斯6种分类器中筛选出最佳的随机森林对渭-库绿洲土地利用类型进行分类,得到2015、2019、2023年土地利用类型分类图,并分析景观生态风险的时空变化特征。结果表明:1)2015—2023年,渭-库绿洲土地利用类型发生较大变化,盐渍地面积占比达到20%以上,且呈波动减少趋势,主要分布在绿洲外围绿洲-荒漠交错区。2)景观生态风险呈“边缘高、中间低”的空间分布规律,具有明显的空间聚集现象。3)高景观生态风险区主要集中在土壤盐渍化程度高的绿洲外围绿洲-荒漠交错区。2015—2019年绿洲内部斑块破碎度增加,景观脆弱度升高,景观生态风险加剧;但2019—2023年通过退地还林以及盐渍化治理使生态环境得以改善。
Soil salinization in the northwest arid zone is a prominent problem and the ecological environment there is fragile.The analysis of land use type change and the landscape index assessment can provide a basis for regional natural environment protection,planning and management.Wei-Ku Oasis is a typical oasis in arid zone in south Xinjiang,and has extraordinary salinization problem.So Landsat-9 and Landsat-8 remote sensing image data were selected to classify the land use tpyes by comparing Random Forest,Support Vector Machine,Gradient Boosting Tree,Classification Regression Tree,Minimum Distance and Plain Bayesian.Random Forest was selected as the optimal classifier to map land use types in 2015,2019 and 2023.Then the spatial and temporal characteristics of landscape ecological risk were analyzed.Results showed that:1)during 2015-2023,the land use types in Wei-Ku Oasis changed a lot.Saline land accounted for more than 20%of the area,distributing in the extra surrouding of the oasis with an decreasing trend.2)The landscape ecological risk showed a spatial distribution pattern of“edge high,center low”,with obvious spatial convergence phenomenon.3)The high risk area was mainly concentrated in the extra surrouding of the oasis like desert-oasis ecotone.The fragmentation of the internal patches in the oasis increased,the landscape vulnerability rose,and the landscape ecological risk was aggravated during 2015-2019.However,the ecological environment had been improved because of the return of the land to forests and the improvement of the saline land during 2019-2023.
作者
张锦明
丁建丽
王瑾杰
赵爽
张子涵
ZHANG Jinming;DING Jianli;WANG Jinjie;ZHAO Shuang;ZHANG Zihan(College of Geography and Remote Sensing Sciences,Xinjiang University,Urumqi Xinjiang 830017;Xinjiang Oasis Ecology Autonomous Region Key Laboratory,Xinjiang University,Urumqi Xinjiang 830017;Xinjiang Institute of Technology,Aksu Xinjiang 843000)
出处
《环境污染与防治》
北大核心
2025年第6期98-102,I0005,I0006,共7页
Environmental Pollution & Control
基金
国家自然科学基金资助项目(No.41961059)
新疆维吾尔自治区自然科学基金重点项目(No.2021D01D06)。
