Assessments of Spatiotemporal Variations and Driving Factors of Ecological Quality in the Greater Penang Conurbation Based on Remote Sensing Ecological Distance Index

The Greater Penang Conurbation, one of the three major conurbations in Malaysia, has experienced rapid urbanization since the beginning of this century, leading to various ecological challenges. The rapid and accurate assessments of ecological quality and its driving factors is crucial for improving ecological quality and achieving sustainable development goals across diverse regions.This study applied the Remote Sensing Ecological Distance Index (RSEDI) model based on Euclidean distance theory and Landsat series images, as the main method and data source respectively, to assess spatiotemporal variations in ecological quality in the Greater Penang Conurbation from 2001 to 2020. Subsequently, the driving factors of ecological quality were assessed through the factor detector and interaction detector components of the Geodetector model. The results showed that: (1) The RSEDI values for the Greater Penang Conurbation in 2001, 2006, 2011, 2016 and 2020 were 0.64, 0.64, 0.67, 0.64 and 0.62, respectively, showing a trend of slightly increasing, then slightly decreasing, and an overall slight decrease. The overall ecological quality was good over the 19-year period but showed a slightly declining trend. (2) Low-ecological-quality areas were mainly in western Penang Island and eastern Kuala Muda, while high-quality areas were concentrated in Kulim, Bandar Baharu, and eastern Penang Island. Ecological quality in South Seberang Perai and eastern Kerian declined significantly after 2011. (3) The Geodetector results indicated that land use was the primary driving factor. Patterns and changes in land use effectively explained the distribution and variations of ecological quality in the Greater Penang Conurbation over the 19-year period. The results can offer scientific guidance for future ecological protection and management of the Greater Penang Conurbation. By early applying the simple and efficient RSEDI model, this study also provides a reference for rapid, accurate ecological quality assessment in tropical coasts, tropical islands, and other tropical regions.