The effect of mangroves on coastline stability

Abstract

Mangrove ecosystems are dynamic environments that provide numerous ecological, economic, and societal benefits, such as shoreline protection, carbon sequestration, and flood protection. These ecosystems are exclusively found in tropical and subtropical regions and thrive at the interface of land and sea. Despite their many benefits, mangroves face significant threats, leading to substantial losses over the past century. The degradation of mangroves compromises flood protection and shoreline stability, increasing the risk of severe coastline erosion and flooding. Current research highlights the role of mangroves in flood protection but presents conflicting theorieson their impact on coastline stability. Two competing theories exist regarding the effect of mangroves on coastline stability, namely the ”land-builders” and the ”land-consolidators” theory. According to the ”land-builders” theory, mangroves actively accumulate sediment and contribute to the expansion of coastlines. In contrast, the ”land-consolidators” theory suggests that mangroves play a more passive role in stabilizing existing landforms and serve as buffers against erosion. The debate on the primary function of mangroves remains unresolved. Furthermore, existing studies often date back over 50 years and are limited by specific hydrodynamic and geomorphic settings, leaving a gap in understanding broad trends. This research aims to bridge this gap through a global assessment of the influence of mangroves on coastline development, complemented by a local assessment to explore detailed interactions in specific case study areas. The study’s objective is to explore the dynamic impact of mangroves on coastline stability through an extensive analysis of historical datasets to identify trends and patterns
in coastline changes associated with mangrove ecosystems. The focus lies on observing trends between coastline stability and the presence of mangroves, the relationship between coastline stability and mangrove forest width, and the influence of the state of mangrove forests (contracting, expanding, stable) on coastline stability.