Anthropogenic pressure on mangrove ecosystems: Quantification and source identification of surficial and trapped debris.

The mangroves are well known for their ecological services and livelihood support to humankind. The mangrove forest is experiencing extreme pressure due to anthropogenic activities, mainly the debris pollution posing great harm to the mangrove ecosystems. The abundance, sources, and composition of surficial and trapped debris items in the six contiguous mangrove regions of Mumbai were studied by the belt-transect and quadrats method. A total number of 3526 surficial debris items (368 kg) were collected from twenty belt transects. The estimated mean surficial debris was 8.8 ± 3.4 pieces/m with a weight of 920 ± 317 g/m. The mean trapped debris was 35 ± 10 pieces/tree and 2514 ± 758 g/tree. Plastic (62.4%) includes carry bags and food wrappers mainly. Shoreline/recreational activity-based debris (38.9%) and other items (32.7%) contributed significantly to the total debris pollution. The study provides evidence that the mangrove ecosystem acts as a natural filter and trap for coastal water debris. The trapped debris is a potential risk to the mangroves due to the barrier created on the canopy surface for the incident solar radiation utilized for photosynthesis. By conducting the cleaning programs in the mangrove vegetation stretches, the ecological disturbances to the mangrove ecosystems can be minimized. Further, the regular removal of trapped debris will complement coastal pollution management. The data generated from this study will help the policymakers and resource managers about the effective control and management of debris pollution in the mangroves region.