1989—2017年乌伦古河流域景观格局及驱动力分析

Landscape pattern evolution and driving force analysis in Ulungur River Basin from 1989 to 2017

为研究乌伦古河流域景观格局时空动态演变及驱动因素,以乌伦古河出山口二台水文站以下流域为研究区,选取1989年,1998年,2006年,2017年4期Landsat系列遥感影像为数据源,综合利用3S技术,通过Fragstats软件计算景观指数,分析景观格局时空演变特征,并结合气象和社会经济数据,探讨乌伦古河流域景观格局变化的驱动因素。结果表明:(1)近30a乌伦古河流域耕地和建设用地面积呈持续增加扩张趋势,水体和湿地面积呈微增加趋势,未利用地呈显著减少趋势,林地面积呈波动增加趋势,草地面积1989—2006年呈减少趋势,2006—2017年呈微弱增加趋势;(2)从斑块类型水平上看,除湿地外,其余各景观类型NP、PD、LSI均呈增加趋势,表明景观破碎程度加剧,结构复杂性增加。从景观水平上看,SHDI和SHEI呈增加趋势,CONTAG呈减少趋势,表明各景观类型面积差异减小,景观丰富度增加,异质性增强,景观连通性降低,空间差异显著;(3)景观格局变化受自然因素、人类活动和社会政策的共同影响。其中,人类活动为主要影响因素,表现形式为人口数量增长,城镇化快速扩张和水利工程的建设。

To study Ulungur River Basin landscape pattern in time and space dynamic evolution and the driving factors,Er’tai hydrological station under river basin was selected in 1989,1998,2006,2017,using 4 series of landsat remote sensing image as the data source and 3S technology.Fragstats software computing landscape index was used to analyze the space-time evolution characteristics of landscape pattern,combining with the meteorological and social and economic data,to discuss Ulungur River Basin landscape pattern change drivers.The results showed that:(1)The area of cultivated land and construction land in Ulungur River Basin showed a continuous increase and expansion trend;the area of water body and wetland showed a slight increase;the unused land showed a significant decrease;the area of forest land showed a fluctuating increase;the area of grassland showed a decreasing trend from 1989 to 2006 and a slight increase trend from 2006 to 2017.(2)From the perspective of patch type,NP,PD and LSI of all landscape types except wetland showed an increasing trend,indicating that the degree of landscape fragmentation and structural complexity increased.From the perspective of landscape level,SHDI and SHEI showed an increasing trend,while CONTAG showed a decreasing trend,indicating that the area difference of various landscape types decreased,landscape richness increased,heterogeneity strengthened,landscape connectivity decreased,and spatial difference was significant.(3)Landscape pattern was changed by natural factors,the combined impact of human activities and social policy.Among them,human activities were the main influencing factors,which were manifested in the growth of population,rapid expansion of urbanization and construction of water conservancy projects.