秦岭山地植被NDVI对气候变化与人类活动的响应

Variation of Vegetation NDVI in Response to Climate Changes and Human Activities in Qinling Mountains

秦岭山地是中国中东部重要的地理界线和山地生态系统最为丰富的区域之一,对气候变化和人类活动的影响较为敏感。基于秦岭山地MODIS NDVI、气温、降水和DEM数据,利用线性趋势法、相关系数、偏相关系数和缓冲区方法,分析了植被NDVI对气候变化与人类活动的响应,结果表明:(1)2000—2015年秦岭山地植被NDVI总体呈线性增加趋势,占总面积的84.84%。减少趋势主要分布在中西部区域(中、高海拔地区)以及河流谷地、盆地,如汉中市、安康市和商洛市等城市附近区域。(2)2000—2014年秦岭山地植被NDVI与气温之间以负相关为主,与降水之间以正相关为主,同时气温、降水对植被NDVI的影响具有交叉作用,其中降水的交叉作用(10.05%)高于气温的作用(9.64%)。(3)市级较县级范围人类活动强烈,植被NDVI在1 km范围变化速率为正(植被增加)、2~5 km范围变化速率为负(植被恶化,可能遭受人为破坏)、6~10 km范围变化速率为正(人类活动相对较弱)、11~15 km范围变化趋于平稳(基本不受人类活动影响)。该研究可为秦岭山地植被生态环境保护和人类活动调整与限制提供科学依据。

The Qinling Mountains are important geographical boundary to central and eastern China. They host a variety of ecological systems,but they are susceptible to climate change and human activities. In this research,data including MODIS NDVI,temperature,precipitation,and DEM were collected from the Qinling mountainous area,and the linear trend method,correlation analysis,partial correlation coefficients analysis and the buffer method were used to analyze the responses of NDVI to climate changes and human activities. The results showed that：（ 1） For the period of 2000-2015,NDVI in the Qinling mountainous area exhibited a trend of linear increase,accounting for 84. 84% of the total area,whereas the areas with a trend of decreasing NDVI were mainly distributed in the mid-west region（ medium and high altitude areas） and some river valleys and basins,such as the areas in the vicinity of the cities of Hanzhong,Ankang and Shangluo.（ 2） During 2000-2014 in the Qinling Mountains,a negative correlation was revealed between NDVI and air temperature,and a positive correlation was revealed between NDVI and precipitation. During this time,air temperature and precipitation had a cross-cutting effect on NDVI,with a higher effect of precipitation（ 10. 05%） than of temperature（ 9. 64%）.（ 3） The change in NDVI was positive in the range of 1 km（ vegetation increased）,negative in the 2 ~ 5 km range（ vegetation deteriorating,possibly subject to vandalism）,positive again in the 6 ~ 10 km range（ human activities were relatively weak）,and stable in the 11 ~ 15 km range（ ultimately unaffected by human activities）. This study will provide a scientific basis for environmental protection of vegetation in the Qinling Mountains and for regulating human activities.