1984—2013年于桥水库流域土地利用变化对植被覆盖度的影响

Impacts of land use changes on vegetation coverage in Yuqiao watershed from 1984 to 2013

基于天津于桥水库流域1984年、1994年、2004年和2013年4个时期的遥感数据,利用像元二分模型、Arc GIS10.2和人机交互式方法解译土地利用类型,分析于桥水库流域1984—2013年内4个时期土地利用变化对植被覆盖度的影响.结果表明:1在植被覆盖度变化方面,植被变化区域有较强的波动性和异质性,研究区内植被覆盖度呈先减小后增大的趋势,且1994年植被覆盖度最低,2004—2013年植被恢复显著,阶段性的退降后,在合理土地利用及生态建设下,植被覆盖度明显好转;2在土地利用方面,土地利用类型变化不大,主要转化类型为耕地转城镇和耕地转园地,且转型过程多发生在低山沟谷和水库周边,易造成水土流失,不利于整体区域的平衡发展,需要采取有效措施.3土地利用变化对植被覆盖度的影响具有复杂性和差异性,不同土地利用类型及其转型过程对植被的恢复效应也存在一定差异,合理搭配林、草、耕地三者间的比例,优化土地资源配置,尽量减少水土流失等不利影响对区域保持良好植被覆盖状态具有重要意义,且人类活动是区域植被变化重要的干扰因子,流域内需要有针对性的土地利用转型和生态系统优化策略.

Based on the remote sensing data of 1984,1994,2004 and 2013 four periods,the impacts of land use change on vegetation coverage in four periods from 1984 to 2013 in Yuqiao watershed of Tianjin were analyzed using Arc GIS10.2,dimidiate pixel model and man-computer interactive method to interpret land use types. The results showed that ：Firstly,from the vegetation coverage change,the vegetation change areas have strong volatility and heterogeneity. The vegetation coverage in research region shows a trend that firstly decreased and then increased. Moreover,the vegetation coverage is lowest in 1994,and the recovery of vegetation is more notable from 2004 to 2013. The vegetation coverage has an obvious improvement after phased decline through the rational land use and ecological construction. Secondly,from the land use,little change can be found in land use types. The main land conversion types show arable land turning to urban land and arable land turning to garden. And the transition process of land use occurr mainly in low mountain-valley and surroundings of reservoir, which can cause soil erosion easily and do harm to the balanced development of the whole region,so effective measures should be taken. Thirdly,the effects of land use change on vegetation coverage are complex and diverse, and the effects of different land use types and transition process on vegetation restoration are also different. So it ′ s significant to make a reasonable proportion of woodland,grassland and arable land and optimize the allocation of land resource so as to minimum the negative effect of soil erosion on keeping good vegetation cover state in the study area. In addition,human activity is the vital interference factor in regional vegetation change,so the targeted land use transformation and ecosystem optimization strategy in this region is required and urgent.