Anthropogenic marine debris in a tropical mangrove conservation area: an insight from Yogyakarta coastal area of Indonesia

Abstract The Baros coastal area in Yogyakarta, a mangrove conservation and ecotourism site, experiences high accumulation of anthropogenic marine debris (AMD) due to its location at the Opak River estuary. In addition, the presence of mangroves can trap debris carried by river flow, causing structural changes and a decrease in the function of the mangrove ecosystem. Therefore, it is necessary to analyze anthropogenic marine debris in mangrove areas as an integrated handling effort, both in terms of policy, control, and implementation. This study assesses mangrove habitat characteristics, AMD distribution, and environmental quality using the Clean Coast Index (CCI) and Hazardous Items Index (HII). The results showed that the characteristics of mangrove habitat, consisting of landward and middle zones, are freshwater/tasteless since they are only submerged during high tide conditions. Meanwhile, the seaward zone is brackish water since it is submerged all the time. The substrate of the landward zone consists of sand and clay, whilst the middle and seaward zones are predominantly composed of sand. Furthermore, our results indicate that macro debris (96%) and plastic waste (76%) dominate the area, with 83% of the study area classified as ‘very dirty’ and 50% under Class IV for hazardous debris, the mangrove ecosystem is at significant risk. The presence of sharp debris poses significant risks to ecosystem health. Given the critical AMD levels, urgent intervention is necessary to prevent further degradation of the mangrove ecosystem.