The Magic Trees- Mangroves
By Eugine Ambaka
Mangroves are facultative halophytes growing along tropical and subtropical coastlines, subjected to high salinity, anoxic substrate, periodical root flooding during high tides, normally referred to as the tidal forests.
The species have unique adaptive anatomical and physiological features that enable their survival. The dicotyledonous woody trees and shrubs form intertidal forests along the shores existing as monospecific patches or bands. True mangroves or exclusive ones, exist in flooded and saline environments, rarely elsewhere, while mangrove associates occur on the landward margin of the mangal, often in non mangal sites like fresh water swamps, rainforests or salt marsh.
True mangroves comprise of 70 species, 28 genera and 20 families. The avicenniaceae and rhizophoraceae families dominate the mangrove communities globally and the tropical temperatures favor their growth as they are intolerant to frost. .
The Kenyan coast has a mangrove cover on both the southern and northern blocks covering a total area of 61,271 Ha, representing a sheer 3% of national forest cover. There are nine species of mangroves occurring in Kenya namely, Rhizophora mucronata (mkoko), Ceriops tagal (Mkandaa), Avicennia marina(Mchu) ,Bruguiera gymnorhiza (Muia), Lumnitzera racemosa (Kikandaa),Xylocarpus granatum (Mkomafi), Heritiera littoralis (Msikundazi),Sonneratia alba(Mlilana), and Xylocarpus moluccensis (Mkomafi dume).
Mangrove areas ensemble across five counties and the geographical coverage by chunk size, stretching from Lamu, Kwale, Kilifi Tana River and Mombasa respectively, managed each by an ecosystem conservator (EC).
Lamu County has an approximate mangrove cover of 37,350 Ha, distributed across several unit areas of Northern swamps, Southern swamps, Pate island swamps, North central swamps Dodori and Mongoni creeks, majorly dominated by Rhizophora and Avicenna species.
Kwale County consists of the Gazi Bay which houses the renowned Mikoko Pamoja project geared towards carbon credit sales, the paltry Diani estuarine forest on river Mwachema mouth, Sii Island, the Vanga Funzi system and Mwache creek amounting to 8,354 Ha.
Kilifi County has a coverage of 8,535 Ha occurring in patchy dwarf pockets across Mtwapa, Ngomeni, Mida creek and Kilifi Takaungu, Tana River County has a coverage of 3,260 Ha interconnected from Ngomeni to Kipini a unique basin ecosystem designated as a Ramsar site due to its high biodiversity and ecosystem importance. Whereas Mombasa County, which faces a high degradation rate has an area cover of 3.771 Ha, occurring across Port Reitz and Tudor creek.
Mangroves are National forests in Kenya; their management is bestowed in the hands of Kenya Forest Service (KFS), singly or in partnership with Kenya Wildlife Service (KWS), if they occur in Marine Protected Areas (MPAs).
Mangroves offer a wide array of ecosystem goods and services of environmental, ecological and economic importance.They include, provisional services that range from both wood and non-wood products. Mangrove wood and timber from Rhizophora and Ceriops species is mostly preferred due to their high quality and resistance to termites. Firewood, as mangroves produce high calorific fuel upon combustion. Food, derived from fisheries which are supported by the mangrove ecosystem both shell and finfish, honey, salt, fodder used for livestock feeds, salt licks, beverage from fermented leaves which produce tea, alcohol and vinegar, and medicinal and cosmetic value from fruits and leaves.
Mangroves offer regulation services through climate control as they sequester carbon four times more compared to terrestrial forest ecosystems, thus form an important contribution as National Appropriate Mitigation Actions (NAMA), coastal erosion control, as mangroves stabilize shorelines by accumulating and coalescing soil particles by their roots, maintaining the coastal integrity as they attenuate storms and tsunamis, bio filtration through accumulation and assimilation of waste, toxins and heavy metals.
Also they contribute to cultural promotion as humans have had a long history of reliance on mangroves for spiritual purposes, holding totemic species or tumulus, the aesthetic value through being a source of traditional knowledge from myths, stories, songs and beauty, explored for tourism and ecotourism for boat rides, boardwalks, hunting, fishing and wildlife viewing.
Another benefit of mangroves is the support of biodiversity as a habitat for migratory birds, juveniles, feeding grounds, reproduction, primary production through photosynthesis, and the energy transfer across various trophic levels supports other biodiversity, nutrient cycling, enrichment of coastal ecosystem and air and water purification.
Mangroves face a series of challenges that threaten their existence both climatic and anthropogenic. Their sustainable use, conservation and protection are key in ensuring their continuous existence overtime. From cutting off human pressure, adopting smart climatic adaptive strategies in their management, strengthening management, community engagement, empowerment and enforcing laws laid down for their protection, the majestic forests are key in tackling climate change and sustaining of coastal livelihoods.