Assessment of coastal ecological restoration effectiveness using an improved remote sensing ecological index: a case study of the Liaohe Estuary

Abstract

Introduction: Coastal ecosystems are experiencing rapid degradation and biodiversity loss, driving large-scale restoration efforts, particularly in China. Traditional methods for evaluating restoration outcomes are often limited by high costs and restricted spatial coverage. Methods: This study introduces an Improved Remote Sensing Ecological Index (IRSEI), which incorporates a salinity-sensitive component into the conventional RSEI framework to better capture the complexity of coastal zones. Results: Applied to the Liaohe Estuary over ten years (2014–2024) using six Landsat 8 images, the index revealed a 23% increase in mean ecological quality and improvements across 48.3% of the area. The spatial recovery exhibited a “core-to-edge” pattern, with gains exceeding 0.2 in restored regions. Discussion: The results underscore the index's utility as a cost-effective and scalable tool for monitoring coastal wetland restoration and supporting adaptive management in transitional ecosystems.