Self-sustenance potential of peri-urban mangroves: a case of Mtwapa creek Kenya

Abstract

Mtwapa creek mangroves are situated in the vicinity of the populous town of Mtwapa and are surrounded by local communities living in the villages along the creek. Both factors pose potential pressure on these peri-urban mangroves hence compromising their sustainability and ability to support coastal livelihoods. This study therefore evaluated the sustenance potential of Mtwapa creek mangroves based on mangrove cover change, structural status and natural regeneration. This was carried out through assessment of tree abundance, dispersion pattern and natural regeneration status along belt transects in three forest patches (Gung’ombe, Kitumbo and Kidongo) in Mtwapa creek and cover change analysis of selected years. The studied siteswere characterised by high stem densities with low basal areas, low utilisation classes and poor forms (poles requiring modification before use or unsuitable for construction accounting for 75.9% of the total stem density). Natural regeneration performance varied among species with Avicennia marina having low survival rates while the other species achieved ≈100% recruitment to successive regeneration classes. Poles were mainly of form 3 (unsuitable for building) indicating selective harvesting. The results show that Mtwapa creek mangrove forest has sufficient natural regeneration but poor tree development thus hindering the forest’s self-sustenance. Additionally and specific to Kidongo, proximity to human settlement contributed greatly to selective harvesting thus compromising the integrity of the forest.