川中丘陵区植被遥感动态监测及其驱动力分析

川中丘陵区是长江上游重要的生态屏障,也是国家退耕还林还草和天然林资源保护工程重点实施区。近年来,由于气候变化与人类活动的影响,该区植被覆盖及生态发生了较大变化。利用该地区2000～2015年MODIS NDVI数据、气象和土地利用数据以及研究区统计数据,采用最大值合成法(MVC)、趋势分析法和相关系数法,分析了川中丘陵区经国家生态工程建设后的植被动态变化特征,并探讨了气候变化和人类活动对植被覆盖的影响。研究结果表明:近15年,川中丘陵区植被呈增加的趋势,增速为5. 84/10 a(P0. 01);31. 58%的区域植被NDVI显著增加,主要分布在嘉陵江中游和岷江中下游,2. 90%的区域植被NDVI显著减少,主要分布在城市中心及周边;研究区植被对降水的敏感性较气温更强,22. 08%的区域面积NDVI与降水是呈显著相关的,仅7. 69%区域面积NDVI与气温是显著的;森林、灌木和草地的NDVI增加明显,各自增加比例超过60%,而建设用地和湿地是NDVI减少最明显的土地利用类型;退耕还林还草和天然林资源保护工程的建设,对川中丘陵区植被覆盖的增长起到了积极作用。

Dynamic Monitoring of Vegetation and Its Driving Force Analysis Using Remoting Sensing in Hilly Area of Central Sichuan Province

The hilly area of central Sichuan is an important ecological barrier in the upstream of the Yangtze River and is also a key implementation area of two improtant projects, namely “Returning Farmland to Forests and Grassland projects ” and “ Natural Forest Protection Project ”.However，recent years there was a great change in vegetation cover and ecology in this area, which is regarded as a consequence of climate change and human activities. Based on the multi-temporal MODIS NDVI data， Meteorological data，Land cover map and other statistical data of the study area, and using maximum value composite (MVC), linear regression and correlation coefficient, this paper aimed to analyze the dynamic changes of vegetation between 2005 and 2015 after introducing the national ecological engineering project, and to identify the impacts of climate change and human activities on the vegetation. The results showed that the vegetation cover in the hilly areas of central Sichuan has been improved, with a rate of 5.84/10 a (P<0.01). NDVI increased siginificantly for 31.58% vegetation area and this change was found in the middle reaches of the Jialing River and in the middle and lower reaches of the Minjiang River; by contrast, NDVI decline for few areas (2.90%), which occurred mainly in the city center and surrounding areas. Vegetation in study area was more sensitive to precipitation compareing its sensitivity to temperature. NDVI showd a siginificant correlation with precipitation for 22.08% of the total study area, while NDVI siginificantly correlation to temperature for 7.69% of the total study area. NDVI of forest, shrub and grassland increased significantly by 60%, while the type of land-use where vegetation NDVI degraded was mainly construction land. The implementation of the“Returning Farmland to Forests and Grassland” and “Natural Forest Protection Project” has played a positive role in improvement of vegetation cover in the hilly area of central Sichuan.