Geomorphic and Climatic Drivers Are Key Determinants of Structural Variability of Mangrove Forests along the Kenyan Coast

Abstract

Mangrove forests occur across a diversity of coastal landforms that influence their structural development and productivity. Preliminary studies in Kenya indicate that mangroves growing in the region north and south of Tana River delta have different structural attributes. We hypothesise a close relationship between mangrove distribution, climate and landform types. Floristic composition of mangroves along the coast of Kenya was characterised and differences illustrated using non-metric multidimensional scaling (nMDS). Other structural properties of mangroves such as tree height, basal area, stand density and standing biomass were also assessed and their differences tested using analysis of variance (ANOVA). A hierarchical cluster analysis was used to compare mangrove species based on structural properties. Additionally, a regression fit model was used to investigate the relationship between mangrove standing biomass and possible drivers of variability. The study revealed significant differences in mangrove tree diameter, tree height, basal area, stand density and standing biomass across the sampled sites. High values of structural complexity were observed in estuarine and deltaic settings with high influence of freshwater input whereas low levels of structural complexity were observed for peri-urban with direct human influence. Our findings suggest that structural variability of mangroves in Kenya is highly influenced by geomorphological and climatic variability along the coast as well as the past and present management regimes of the forest.

Eco-Engineering Mangrove Restoration at Gazi Bay, Kenya

“…This might lead to disparities in stem diameter and height thereby weakening the correlation. Such weak correlations have been reported elsewhere, for instance in Mombasa and Mtwapa, Kenya [92], where the mangrove ecosystem is predisposed to human and environmental stressors [93,94]. Overall, conditions along the shoreline of Gazi Bay depict a picture of a highly degraded and exposed mangrove site.…”

Changes in Mangrove Cover and Exposure to Coastal Hazards in Kenya

“…There are about 136,000 km 2 of mangroves in 108 countries [3]. Mangrove distribution is strongly influenced by geomorphic and climatic drivers (e.g., temperature and moisture) [4,5]. Asia has the largest extent of the world's mangroves (42%), followed by Africa (20%), North and Central America (15%), Oceania (12%) and South America (11%) [6].…”