Mangrove exploitation effects on biodiversity and ecosystem services

Abstract

Mangrove forests are one of the most important coastal ecosystems as they support many local communities. However, over the last two decades harvesting of mangrove forests has been extensive with effects on mangrove biodiversity and ecosystem services. We investigate the effect of mangrove harvesting on tree biodiversity in South Sulawesi, Indonesia. Using two line transects each in ten mangrove forests, mangrove composition, species dominance, density, frequency, coverage, and stem diameter and diversity were recorded. Interviews detailing provisioning ecosystem services were also conducted with local forestry and fishery workers to determine the level of exploitation. Ten mangrove species were recorded (Avicennia alba, Bruguiera gymnorrhiza, Ceriops tagal, Excoecaria agallocha, Lumnitzera racemosa, Nypa fruticans, Rhizophora apiculata, Rhizophora mucronata, Rhizophora stylosa, and Sonneratia alba) belonging to six families (Avicenniaceae, Rhizophoraceae, Euphorbiaceae, Combretaceae, Arecaceae and Sonneratiaceae). Mangrove forests are now dominated by saplings and seedlings, with few trees above 15 cm diameter at breast height. Rhizophora sp. were found to be the most important and dominant species. Rhizophora sp. was the most widely used as it was deemed the most suitable for firewood and charcoal. In addition, it is the main species planted in mangrove restoration projects, which have focused on establishing production forest rather than restoring natural species composition and structure. Despite the decrease in biodiversity, the mangroves still provide a wide range of ecosystem services to the communities in the area.