Mangrove forests on road to recovery after years of plunder
A woman holds mangrove seedling for planting on shores of River Sabaki in Malindi on February
What you need to know:
- By the beginning of the 20th century, Kenya was exporting an annual average of 483,000 mangrove poles per year from Lamu forests alone.
- Over-exploitation and degradation of mangrove forests led to a Presidential ban on export of mangrove poles from Kenya since 1982. Another ban was instituted in 1997 against use of mangroves for construction, but it was lifted in 2003.
Kenya is making strides in restoring its mangrove cover. Formerly blighted by decades of plunder, new research shows that the country’s total area of mangroves currently estimated at 54,430 hectares (ha), has gained some 578 ha between 2016 and 2020.
The Status of Mangroves in the Western Indian Ocean Region 2022 report released by Global Mangrove Watch (GMW) on July 18 credited the gains to regeneration accelerated by natural expansion following sedimentation and restoration efforts.
The survey also shows that Kenya only lost 1,139 ha in 20 years (1996-2016) -a drop from 54,990 ha in 1996 to 53,852 ha in 2016—nothing like what it previously lost in decades gone by. About 18 per cent of Kenya’s mangroves were lost between 1985 and 2010 and extensive parts between the 1970s and 1980s, with estimates putting the loss at as high as 50 per cent of original mangrove cover over the past 50 years.
According to the assessment, losses have been especially high in the peri- urban mangroves of Mombasa that lost 70 to 80 per cent in the past three decades owing to their proximity to the Port of Mombasa where oil spills from five tanker accidents between 1983-1993 spilled 391,680 tonnes of oil, and another spill in 2005 released 200 tonnes of crude oil into the environment, affecting 234 ha of mangroves in Port Reitz.
“Illegal dumping of used oils from offshore boats and ships by small-scale traders causes additional small-scale spills, affecting young mangroves around undesignated landing points,” added the study.
By the beginning of the 20th century, Kenya was exporting an annual average of 483,000 mangrove poles per year from Lamu forests alone. Over-exploitation and degradation of mangrove forests led to a Presidential ban on export of mangrove poles from Kenya since 1982. Another ban was instituted in 1997 against use of mangroves for construction, but it was lifted in 2003.
Other significant losses have been driven by exploitation for wood resources, land clearance for salt production and port development. There has also been reported widespread dieback of the mangrove Sonneratia alba caused by wood-boring insect infestations in several areas.
Recognised as a hardy ally in the face of climate change, filtering water pollution, protecting the terrestrial ecosystems against extreme weather and rising sea levels and capturing carbon—Kenya’s mangrove biomass and sediment store up 77.3 metric tonnes of carbon dioxide or three percent of the country’s total fossil fuel carbon emissions each year, according to the GMW data.
According to the present analysis, they contribute Sh9.4 billion in annual economic net benefits to the national economy. Mangroves contribute approximately 70 per cent to the wood requirements by coastal people in Kenya for timber, firewood and charcoal production, with an estimated economic value of approximately Sh2.85 billion million per year.
Hotspots of blue carbon sequestration (the process of capturing and storing atmospheric carbon dioxide) include the mangroves of Lamu-Tana region districts and Kwale where 70 per cent are found.
There are at least 3,351 ha available for mangrove restoration along the Kenyan coast, where community-based co-management of mangroves has seen promising but variable results in the country.
“Past restoration efforts in the country appear to have made a notable difference,” indicates the report, “Total mangrove cover in Kenya increased by some 300 ha since 2015. Areas of increase were particularly noticeable in Vanga in Kwale (235 ha), Ngomeni (665 ha), Kilifi (247 ha) and Ungwana Bay in Lamu (424 ha).”
