摘要
水库等电力工程的修建和退耕还林政策在黄土高原特别是黄河中游地区的实施,有效地减轻了水土流失现象,并改善了生态环境,研究该区域典型城市的植被覆盖度的动态变化及其风险状况对于新时期黄河流域生态环境高质量发展具有重要意义和价值。本研究基于冷热点分析理论的Getis-Ord G^*统计量、Mann-Kendall趋势检验、Hurst指数和Pettitt检验法,识别了西安市2000—2013年植被覆盖度的冷热点分布,捕捉了植被覆盖度Getis-Ord G^*统计量的变化趋势和突变点,采用概率分布函数分析了植被覆盖度冷热点发生的概率风险大小。结果表明:1)西安市植被覆盖度存在冷热点,且多年平均植被覆盖度热点和冷点占全市总面积的5.27%和13.91%;2)海拔较高的山区和海拔较低的城区周边植被覆盖度Getis-Ord G^*统计量呈现显著减少,海拔较低的蓝田县北部和临潼区南部呈现显著增加,分别占全市总面积的15.93%和12.89%,未来在城区、蓝田县北部和临潼区南部植被覆盖度可能会呈现高值聚集的状态;3)西安市植被覆盖度Getis-Ord G^*统计量在2004—2008年发生了突变,集中在蓝田县北部和临潼区南部以及城区周边;4)周至县山区、鄠邑区山区和长安区山区等高海拔地区出现热点区域的概率较高,城区和蓝田县北部、临潼区南部低海拔区域出现冷点的概率较高。林业生产活动和城市园林绿化等人类活动的增加对植被变化具有显著影响。研究成果有助于进一步了解西安市植被覆盖变化情况,可以为下一步加强生态环境治理和绿化工作以及降低植被退化风险提供科学依据。
The construction of reservoirs and other power projects,and the implementation of the policy of returning farmland to forests in the Loess Plateau,especially in the middle reaches of the Yellow River,have effectively reduced soil erosion,improved the ecological environment.Studying the dynamic changes of vegetation coverage and risk status of typical cities in the region is of great significance and value to the high-quality development of the ecological environment of the Yellow River Basin in the new period.Based on the Getis-Ord G^* statistic theory,Mann-Kendall trend test,Hurst exponent and Pettitt test,this study identifies the distribution of cold spots and hot spots of vegetation coverage in Xi’an from 2000 to 2013,and captures the trend and the change-points of the Getis-Ord G^* statistic of vegetation coverage.The probability risk of cold spots and hot spots of vegetation coverage is analyzed by probability distribution function.The results show that:1)The hot spots and cold spots of average annual vegetation coverage account for 5.27% and 13.91%of the total area of the city.2)The Getis-Ord G^* value of the vegetation coverage in the mountainous areas with higher altitudes and in urban areas with lower elevations is significantly reduced,and the Getis-Ord G*value in the northern part of Lantian County and the southern part of Lintong District shows the significant increase.3)The Getis-Ord G^* value of the vegetation coverage in Xi’an has significant change-point from 2004 to 2008,concentrates in the northern part of Lantian County and the southern part of Lintong District.4)The probability of hot spots appearing in the mountainous areas of Zhouzhi County,Huyi District,Chang’an District is higher,and the probability of cold spots appearing in the low altitude areas of the urban areas,the northern part of Lantian County and the southern part of Lintong District in is higher.Increases in human activities such as forestry production activities and urban landscaping have a significant impact on vegetation changes.The research results will help to further understand the changes in vegetation cover in Xi’an,and provide scientific support for the next step of strengthening ecological environment management,greening work and reducing the risk of vegetation degradation.
作者
邹彬
ZOU Bin(State Grid Shaanxi Electric Power Company,Xi’an 710032,China)
出处
《西安理工大学学报》
CAS
北大核心
2020年第2期197-204,共8页
Journal of Xi'an University of Technology
关键词
植被覆盖度
黄河流域典型城市
风险
生态环境
vegetation coverage
typical cities in the Yellow River Basin
risk
ecological environment
