Causes and Perceptions of Environmental Change in the Mangroves of Rufiji Delta, Tanzania Implications for Sustainable Livelihood and Conservation

University dissertation from Stockholm : Department of Physical Geography, Stockholm University

Abstract: Mangroves are ecosystems with enormous ecological importance, supporting both terrestrial and marine food webs. They provide ecosystem services (e.g. food, medicines, fuel, constructing material) to communities near and far. Despite their importance, mangrove areas are facing numerous threats. Based on neo-Malthusian narratives, population growth is an alleged main cause of mangrove degradation, especially in developing countries. This thesis investigates the Rufiji Delta mangroves, from several perspectives including: recent history, present condition, use of land and other resources, as well as actual and potential impacts of government policies and management on mangrove conservation and for the local communities. Of special interest is the examination of multiple, and often diverging, perceptions concerning these variables and processes. Both qualitative and quantitative methods have been used. Interviews were conducted with relevant stakeholders. Analysis of census data (1957–2012), to ascertain population trends in the Delta, spans the pre- and post-Ujamaa villagization programme. Old maps were scanned and geo-referenced in GIS to compare administrative units between successive censuses. Synthetic Aperture Radar (SAR) imagery, spanning from 1994 to 2010, was explored for analysis of mangrove dynamics and stand structure. The analysis of population trends in the Delta revealed decreasing population in the South Delta and a low population increase in the North Delta, in comparison with neighbouring non-delta areas. This is contrary to the assumption by government authorities that the Ujamaa villagization programme instigated migration to the Delta which caused mangrove degradation. Spatio-temporal changes in mangrove area and land use, observed and confirmed by SAR imagery and field control, is part of the highly dynamic eco-hydrology and geomorphology of the delta ecosystem. While some areas have been converted to rice farms, other areas have gained in mangrove coverage. Overexploitation of mangroves occurs, primarily by external actors, and both local communities and representatives of government authorities ascribe this to lack of financial and human resources to enforce current laws and regulations. Ever since the Rufiji mangrove forest was declared as a forest reserve in 1898, it has been a legal quagmire, with legally established village land within a state forest where human habitation is prohibited by law. This thesis explores management approaches that will embrace conservation with sustainable development. That can only be achieved when local communities are legally recognized as inhabitants and important stakeholders in the conservation of the Delta. A conservation approach that removes land tenure uncertainty among the local communities and takes into consideration the dynamic nature of the Delta must be devised for the Rufiji mangroves.