Evaluation and analysis of post-seismic restoration of ecological security in Wenchuan using remote sensing and GIS

Aiming at studying the ecological security in Wenchuan, China, where the ecological system had been greatly damaged by the earthquake in 2008, an evaluation indicators system was established based on the pressure–state–response (PSR) model, and the indicators were derived from remote sensing images, meteorological data, and statistical data. Ecological security indexes in 2007, 2008, and 2013 were calculated through a comprehensive index method. Then the spatio-temporal analysis on ecological security was conducted. Particularly, the changes of ecological security were centrally analyzed concerning topography, land use types, vegetation coverage, as well as ecological PSR. It is found that the ecological security in Wenchuan presented a distinct vertical-belt distribution. It was damaged by the earthquake, however, it had been improved obviously by 2013, which still did not reach the level in 2007. Meanwhile, the epicentre, the Minjiang River and the southwestern mountains have typically regional characteristics, where the changes of ecological security were analyzed elaborately. The ecological security of these regions had been differently restored compared with 2007. However, there were still some regions with unsafe ecological security. Finally, the studied area was divided into four regions with different protection strategies and some recommendations were provided for further ecological protection