Current Status, Utilization, Succession and Zonation of Mangrove Ecosystem along Mida Creek, Coast Province, Kenya

Abstract

Mangrove forests have been destroyed as a result of human activities and this is a threat to the mangrove ecosystem and the living things depending on them. Research on the current status, utilization, succession and zonation of mangrove ecosystem was conducted along Mida Creek, Coast Province, Kenya from September 2009 to February 2010. Objectives were to: assess the changes in the floristic composition of the mangrove forest; identify the most preferred mangrove species; investigate whether accessibility determines utilization of mangrove species; examine whether harvesting of mangroves affect their succession and to explore the current mangrove forest management policies and their effectiveness. Point- Centred Quarter Method (PCQM) was used to collect data that was used to investigate whether accessibility into the mangrove forest determines their utilization and to assess whether succession of the mangroves is affected by their utilization. Questionnaires were distributed and interviews conducted to explore the effectiveness of government policies/ legislation governing utilization of the mangroves and to investigate the most preferred mangrove species by the local community and other users. The total number of respondents interviewed was 136 one from each household out of the 210 households in Mida Creek. Two sets of Aerial photographs (1992 and 2006) were processed and interpreted to assess the temporal changes in the floristic composition of the mangrove forest. Questionnaires were coded and entered into Statistical Package for Social Sciences (SPSS). Analysis of Variance (ANOVA) was performed to investigate whether accessibility of mangroves determine their utilization. Regression analysis was performed to assess whether utilization of the mangroves affect their succession. Importance value was calculated to assess the forest structure. Descriptive statistics were performed to summarize the current mangrove forest management policies and their effectiveness. Results showed that the floristic composition of mangrove forest in Mida Creek has changed between year 1992 and 2006; Area covering mangroves has decreased as follows: Rhizophora mucronata (Rm); 65.09-63.93ha; Avicennia marina (Am); 344.99-310.63ha; Ceriops tagal (Ct); 225.12-223.82ha; Rm and Ct; 52.87-50.22ha; Ct and Am; 143.69- 140.29ha; Rm and Am; 44.36-41.27ha; Rm and Bg; 212.75-199.75ha; Rm and Sonneratia alba (Sa); 47.64-46.32ha; Rm, Ct and Bruguiera gymnorrhiza (Bg); 129.07-128.12ha; Rm, Am, Ct and Bg; 472.44-428.46ha. ANOVA test showed that there was a significant difference (F=3.277; df=2; p=0.040) between the number of cut mangroves in the near settlements, middle and shoreline hence accessibility determines utilization. Results also showed that Rhizophora mucronata is the most preferred mangrove species. Regression analysis showed that there was a relationship between the number of mangrove seedling and the number of cut mangroves (F=8.529, df=1, R=0.198, P=0.004). Utilization of mangroves affects their succession. The policies/legislation governing mangrove utilization have been less effective. Rhizophora mucronata and Ceriops tagal were the key species in Mida Creek. Mangrove forest area in Mida Creek has decreased over a period of time.