Spatial-Temporal Patterns of Kisakasaka Mangrove Forest in Zanzibar, Tanzania

In Zanzibar, mangroves are highly valued for their biological variety and aesthetic appeal. However, natural factors like climate change, variability and human activities, especially around the coast, have been affecting marine biodiversity, including the mangroves, which had numerous advantages to the ocean and to human life (Khatib, 2019; Khamis et al., 2017). This study assesses the spatial-temporal patterns of changes in Kisakasaka mangrove forests between 1990 and 2020. The changes in mangrove patterns were detected using various techniques, such as ground trothing, visual analysis, and classification of two classes (i.e. mangrove class and bare land class) using GIS version 10.4. The overall accuracies ranged between 85.4 and 97%. The kappa coefficients (ĸ) were in the range of 0.76–0.93 in five years intervals of 1990-1995, 1995-2000, 2000-2005, 2005-2010, 2010-2015 and 2015-2020. The results show the mangrove declined by 70ha, 50ha, 15ha, 3ha, 7ha and 2ha, respectively. The findings of this study show that there were some years that experienced a drastic decline in mangrove forests, like 1990, 1995 and 2000, due to the termination of community projects of mangrove conservation. However, in recent years, the mangrove area has started to recover from degradation. For instance, in 2020, 85 hectares of land that was barren in 2015 was successfully restored to a thriving mangrove ecosystem. This remarkable transformation can be attributed to increased community engagement in mangrove conservation, driven by extensive government-led education initiatives. Furthermore, people are now encouraged to use other sources of energy like gas and electricity that are environmentally friendly. The findings show that the major problem of mangrove degradation at Kisakasaka was caused by overpopulation, lack of alternate sources of income, poor forest management, and widespread clearing of mangroves for charcoal, firewood, and construction materials. The study concludes that the community's reliance on the forest is in jeopardy and that the mangrove forest's transformation has had a significant impact on the community's livelihood. It is recommended that regeneration and rehabilitation be carried out to revitalize the forest, adequate structures should be established, and the community should find other means of income generation besides relying on mangrove products.