Perceptions, Knowledge Systems, and Ecological Indicators in Evaluating Mangrove Ecosystem Health in Zanzibar

Zanzibar's mangrove forests provide essential ecological, commercial, and cultural functions, but they are under increasing strain from environmental change and human activity. With an emphasis on variations influenced by occupation, age, and the location of coastal settlements, this study attempts to investigate how coastal residents in Zanzibar define, perceive, and assess the health of mangrove ecosystems. In order to methodically capture local ecological knowledge and temporal views, data were meticulously gathered through participatory workshops with 220 participants using integrated methodologies such as participatory mapping, historical timeline reconstruction, and organized discussions. Mangrove health was regularly evaluated by communities using metrics such as species richness, biodiversity, forest structure, and resource accessibility. Age was a significant factor (χ² = 27.6, df = 11, p = 0.0037), with older participants exhibiting broader and more detailed ecological understanding. However, statistical analysis showed no significant variation in ecological knowledge across villages (χ² = 18.6, df = 11, p = 0.069) or occupations (χ² = 12.4, df = 11, p = 0.3329). Thus, there were clear intergenerational differences: younger participants gave priority to habitat quality and biodiversity conservation, whereas seniors stressed long-term decrease since the 1970s. Thirty-one indicators of ecosystem health were found among all participants, with biological indicators making up 67.7% of the total. Results show that mangrove health has significantly declined due to harvesting, urbanization, aquaculture, and weather events, but there is also evidence of resilience and rebound. The study emphasizes how important traditional ecological knowledge is for developing adaptable, community-driven conservation and sustainable mangrove management practices.