Spatio-temporal land use change and loss of mangrove forest in two coastal cities in Tanzania and the perceived implications on provisioning of ecosystem services

Abstract

Mangroves supply a diverse range of products and ecological services, both locally and globally. However, our understanding of the anthropogenic drivers of land use change and mangrove loss, as well as loss of ecosystem services in Tanzanian coastal cities is limited. We conducted a study in two selected estuaries: Mtoni in Dar es Salaam and Kisiju in the Pwani area. We determined spatio-temporal land use change in 1980, 2000, and 2020, and conducted socioeconomic questionnaires to examine change drivers and perceived implications on ecosystem services provisioning. We revealed that over the last four decades, there have been considerable changes in land use that resulted in mangrove losses or transitions to the other cover type. The closed mangroves in the Mtoni estuary decreased by −95.63 ha from 1980 to 2000, and -109.87 ha from 2000 to 2020. In the Kisiju estuary from 1980 to 2000, the fraction of closed mangroves declined by −74.5 ha and 23.5 ha between 2000 and 2020. The emergence of open mangroves by different fractions is a result of losses occurred on closed mangroves through forest clearing for charcoal production, firewood, and building resulting in barren land. The attributing drivers of change population growth and the associated unsustainable land use practices related to farming, cutting trees for charcoal making, fuelwood, and building materials. Climate change events such as storms, rising sea levels and temperatures as well as flood events have contributed to death of mangroves. The loss of ecosystem services such as reduced fish catch, deterioration of critical breeding grounds for fish, exposure to flood hazards, storms and sedimentation are the perceived outcomes of the loss of mangroves and unsustainable land use change. The loss of mangroves has reduces their ability to protect coastal communities from flooding and loss of the potential to sequester carbon and mitigate climate change. Our findings, recommended for improving mangrove conservation and adaptive integrated approaches are needed to conserve these important ecosystems.