Construction and optimization of the ecological security pattern in Yiyang County based on the remote sensing ecological index

With the advantages of large-scale rapid real-time monitoring, the remote sensing technology is widely used in the field of the ecological environment and has become an effective method of evaluating regional ecological security. To explore the current situation and the existing problems of regional ecological security and to provide a more comprehensive optimum design, this paper applies the remote sensing ecological index (RSEI) to evaluate the ecological environment quality and to examine the stability of ecological quality based on a multi-period data of Yiyang County and select the ecological source region. In addition, this study also seeks to construct a “point-line-plane” ecological security pattern by the minimum cumulative resistance model (MCR) and the gravity model. Results show that the average RSEI values of Yiyang County in 2010, 2015, and 2019 were 0.820 3, 0.846 6, and 0.734 9 respectively. The rising and falling pattern shows that the ecological quality was in a good and stable state. This research identified 17 ecological source regions, 35 general corridors, 13 key corridors and 46 ecological nodes, which constitute the ecological security pattern of Yiyang County. Three ecological sources were added after the optimization, with a total area of 21.40 km2. In addition, 10 new ecological corridors were added, with a total length of 137.48 km and 24 stepping-stone patches and 10 ecological nodes were also increased. A strategic layout framework of ecological security for “one belt, two areas and multiple axes” has been formed, based on the core elements like ecological sources, ecological corridors. Results from this research provide some scientific evidences for delineating and improving the ecological function zones and some references for identifying the ecological source regions in the construction of the ecological security pattern.