Yancheng National Nature reserve is included in UNESCO international man and the biosphere reserve area with the critical purpose of conserving, protecting, and providing overwintering habitat for endangered bird species as Red-crane bird. The core zone of the nature reserve is strict, guarded, and prohibited from any anthropogenic pressure. However, Remote sensing technology such as multispectral and hyperspectral satellite imaging with UAV technology was used in surveilling and monitoring the vegetation distribution pattern changes and phenology of its ecosystem from 2003-2018 (15 Years). Support vector machine and Maximum Likelihood classification were used as a multiple classifier in the training of vegetation ecotones, which helps in solving the confusion matrix and maximizing the accuracy assessment of various vegetation land cover in YNNR. Furthermore, Suaeda Salsa, a native grass in the zone and mostly preferred habitat for foraging, breeding, and overwintering by these endangered bird species, are extensively being threatened by invasive cordgrass Spartina Alterniflora and its native counterpart Phragmites Australis. These salt marshes are shrinking out the living and dominating the ecosystem of Suaeda Salsa in YNNR. Also, Spartina Alterniflora is currently suffering from cliff erosion at the shoreline, which in turn reverses the morphology and growth pattern of the cordgrass from seaward direction growth to the inland direction.