Spatial-temporal dynamic change of fractional vegetation coverage and its driving factors in Liaohe Conservation Area

Based on the data of MODIS NDVI at 500-meter spatial resolution and the Landsat TM/OLI images, a 30-meter fractional vegetation coverage (FVC) data set of Liaohe Conservation Area was constructed, covering the time period 2000-2018. The study analyzed the spatial-temporal dynamics of FVC and its driving factors before and after the establishment of the Liaohe Conservation Area, during 2000 to 2009 and 2011 to 2018. The results showed that from 2000 to 2018, FVC of Liaohe Conservation Area showed a slightly upward overall trend, and that of the period between 2000 and 2009 witnessed an increasing trend with 0.67%/a, then declined with fluctuation during 2010-2018 with a negative slope -0.27%/a. A downward trend of FVC occurred at regional scale, the area of which mainly distributed on both sides of low-lying river reach. Comparing with the base year (2010), slightly restoration of vegetation in Liaohe Conservation Area presented during 2012-2014, also appeared the degradation trend from 2015 to 2018. By comparing the difference between the simulated FVC with the actual FVC in Liaohe Conservation Area, it was found that in the period of 2011-2018 the influence of human activities on FVC increased to 1.12%, and the restoration of vegetation in 2014 was significantly attributed to human activities. Overall, since the establishment of Liaohe Conservation Area, there was a tendency that FVC increased at first and then declined, which was attributed to the climate change. Furthermore, human activities had a positive effect on vegetation especially on vegetation restoration, the contribution of which was up to 8.42%.