ASSESSMENT OF THE STRUCTURAL VARIABILITY OF MANGROVE FORESTS ALONG THE KENYAN COAST

Abstract

Mangrove forests play important roles benefit both the coastal communities and nation at large. However, no comparisons on structural variations of these ecosystems have ever been done and made available to forest managers and policy makers. This study aimed at characterizing structure of mangrove of the forests with the purpose of obtaining detailed data and information necessary for national management plan. A total of 627plots were established along entire belt transects identified and oriented perpendicular to the shoreline. The data was analyzed using Analysis-of-Variance (ANOVA) to assess possible spatial structural variations between mangrove species and among the mangrove ecosystems. The results show that the structural attributes: stem density, tree height, Diameter-at-Breast Height (DBH) and pole quality differed significantly between different mangrove species. Only tree height was significantly different between mangrove forests. Rhizophora mucronata recorded 292±131stems/ha, and had the highest stem densities while Lumnitzera racemosa had the lowest density with 2±1stems/ha. Basal area was highest in R. mucronata with 6.6±1.6m2 and lowest in L. racemosa with 0.3±0.1m2.The tallest mangrove species was Sonneratia alba with 6.6±2.4 m while the shortest mangrove species wasH. littoralis with 0.5±0.2m. Comparing the mangrove forests, tree height was highest in Kiunga Marine National Reserve (KMNR) with 7.5±3.8m and lowest in Mtwapa with 3.6±1m. Sonneratia alba and H. littoralis also had the highest and lowest DBH with 13.1±7.7cm and 0.5±0.2cm, respectively. Species diversity varied significantly with A. marina, C. tagal, and R. mucronata being the most dominant compared with the other species. The species R. mucronata and L. racemosa had the highest and lowest percentages of their poles of merchantable as well as non-merchantable