The structure of the mangrove forests of Kiunga-Pate Island conservancies in Kenya are shaped by selective harvesting and natural mortalities

Abstract

Lamu archipelago is endowed with rich biodiversity including Kenya's largest continuous acreage of mangroves (approx. 33,000 ha) among other ecosystems making it a hotspot for management and conservation efforts. Yet, the involvement of the local community in management in this area is still in its infancy, with threats from large-scale developments, population growth, and climate change on the rise. Here, the structural status of the mangroves around Pate Island and Kiunga Marine National Reserve (KMNR) was assessed and information applied to guide and promote community-based conservation, as well as the development of the national mangrove management plan. Stratified and random spot sampling was used to collect vegetation data and mapping undertaken to estimate the mangrove cover change between 1995 and 2014. There was a loss in mangrove cover of up to 22.6% over 19years. A substantial loss was associated with illegal selective harvesting outside the KMNR, some clear-cutting to pave way for large-scale development and natural mortality of overgrown mature trees within the KMNR. In particular, natural mortality was found to hinder natural regeneration within the KMNR. The results however showed a generally stable system with potentially sustainable levels of natural regeneration and recoveries in isolated patches. These results reveal two management actions: raising awareness of mangrove ecosystems' ecological value and controlling old-growth harvesting in the KMNR to facilitate natural regeneration and development of young vigorous forest through gap creation. This information provides a strong foundation for conservation planning including future mangrove restoration and conservation activities. A comprehensive coordinated conservation strategy that links conservation to communities, livelihoods, and governance frameworks is recommended.