Ecosystem Services of Small Tropical Estuaries: Review, Synthesis, and Future from an Indian Perspective

Estuaries, being prominent ecotones of aquatic environment, provide a ‘paragon of virtue’ beneficial to humans. The multitude of ecosystem services provided by these distinct yet fragile environments has gone unnoticed and less documented. In India, the majority of available information on estuarine functioning, health, biodiversity, and management is centred on large estuaries. Small tropical estuaries, on the other hand, offer adequate scope for ensuring better ecosystem services due to their unique morphology, hydrographic characteristics, high productivity, and ease of enforcing management measures. The various ecosystem services offered by these small and unexplored tropical estuaries, in terms of their quantities and values, still need to be discovered. Such information is crucial for the successful management and to inform future decision-making. In addition to this, these ecosystems present several challenges to policymakers. These estuaries require extensive research due to their high ecological dynamics, rapidly shifting salinity gradients, increased risk of imperilment from excessive sedimentation, and anthropogenic activities. Thus, studies from the Indian subcontinent are included in this review, to emphasize the significance of different ecosystem services, characterizes each of these services, indicates their significance in small tropical estuaries, and to assess the benefits they offer. It also covers the relevant problems that these types of estuaries face, focusing on the necessity of gaining a greater understanding of the ecological complexities to guide future management. We anticipate that this review will help us better understand the four main services provided by estuaries, as well as the threats these estuaries face, how to best use the resources available to us, and how to propose better livelihood options for achieving the Sustainable Development Goals in the context of the “blue economy”. Mapping various ecosystem services can thus help provide better management options and thus contribute to the overall protection of these vulnerable estuarine ecosystems.