[H-GG01] Dialogues on natural resources and environment between earth and social sciences

[HGG01-03] The Waste Deposition Effects on the Functions of Mangrove Ecosystem in Coastal Areas Adjacent to Cities in Northwestern India

*Karin Uruma¹, Nobuhito Ohte¹ (1.Department of Social Informatics, Graduate School of Informatics, Kyoto University)

Keywords:Mangrove Forests, Ecosystem, Waste deposition, Pollution

Mangrove forests in the intertidal and brackish waters of the tropics and subtropics form rich ecosystems. Mangrove ecosystems have various functions such as carbon sequestration, seawater purification, and disaster prevention. Their importance to society has been recognized worldwide. However, the area of mangrove forests is decreasing year by year due to anthropogenic activities such as deforestation and water pollution caused by development in coastal areas, as well as climate change. In addition, the amount of garbage deposited in mangrove forests from land areas through rivers and drainage channels has increased rapidly in recent decades in populated areas, and there is concern about various adverse effects. The study site, Versova in Mumbai district, northwest India (hereafter referred to as Versova), is located near the mega-city of Mumbai, and the amount of litter deposited in the mangrove forests through rivers and drainage channels has been increasing. In Versova, the increase in waste deposition in rivers and on the mangrove forest floor since the 2000s has led to a drastic decrease in the number of fish and shellfish species that used to inhabit the mangrove forest floor. The area is a fishing village that has existed since the 16th century and has mainly fished around the mangrove forests, but many fishermen have been unable to continue fishing due to the decrease in fishing resources. Although there have been some studies on the impact of litter accumulation on fishery resources and fishermen's livelihoods, the impact on the ecosystem function of mangrove forests has not yet been sufficiently clarified. However, there are studies that point out the possibility that the soil and water contamination led by the litter deposition may have adverse effects on mangrove plants in the future. For example, previous studies have shown that accumulated litter can inhibit seedling implantation. However, previous studies have only investigated the type, amount, and distribution of litter deposited in mangrove forests, and few studies have focused on the direct effects of litter deposition on mangrove forests. In this study, the following three surveys were conducted to clarify the effects of litter accumulation and the resulting soil and water pollution on mangrove forest habitats: (1) Tree survey and microtopographic survey of mangrove forests. (2) Investigation of water and soil quality. (3) Interviews with fishermen and sampling of fish and shellfish. The surveys were conducted during the dry and rainy seasons in Versova, and the results of the dry season will be presented in this presentation. The knowledge and information obtained from this study can be used to develop and implement concrete and effective environmental conservation measures.