Long-term monitoring of mangrove expansion and shoreline degradation in the Farasan Islands using Landsat data (1993–2023)

Abstract

Mangroves are among the most productive ecosystems on Earth, but due to urbanization and deforestation activities, this ecosystem has been declining for several decades. This study focused on the Farasan Al-Kabir Islands and utilized Landsat satellite imagery to comprehensively assess the changes in mangroves and the overall status of islands from 1993 to 2023. A time series analysis spanning three decades with 5 year intervals provides authentic and significant results. The findings indicate a positive trend in both the vegetation index and moisture index, with the most notable effects occurring between 2013 and 2023. However, the shoreline of the Farasan Al-Kabir Islands has decreased, with degradations being a primary concern. The reduction in shoreline highlights an alarming situation and the impact of global warming on islands. Despite these challenges, the mangrove area has increased by 3.55 square kilometres over the past three decades, with significant growth observed on eastern and northern sides of the Farasan Al-Kabir Islands, as well as on Zifaf Island. This study underscores resilience of mangrove ecosystems in the Farasan Al-Kabir, despite the ongoing threats posed by sea-level rise and shoreline degradations. The expansion of mangrove cover is a positive indicator that reflects the adaptive capacity of these ecosystems. However, the simultaneous reduction in shoreline due to degradations presents a serious challenge that could threaten the long-term sustainability of islands coastal environments.