The projects of the Mangroves Initiative

Mangroves are threatened by agricultural development (rice, oil palm and teak plantations, livestock, pollution spread by the intensive use of inputs in farming) and sedimentation from watershed erosion. Mangrove mortality encourages colonisation by an invasive fern native to Costa Rica called Negra Forra (Acrostrichum aureum).

Restoration:
As this plant cannot survive in sea water, the proposed technique involves flooding the plains by opening up channels according to the local microtopography. The plain will then be recolonised by mangroves, either through seeding with mangrove propagules or by transplanting mangrove plants from nurseries set up beside the sites undergoing restoration.

The mangrove area, which is one of the most susceptible, has been heavily deforested for urbanisation, salt production, mariculture (shrimp) and the harvesting of mangrove bark for the leather industry. Today, the greatest threats are posed by the constant encroachment of agriculture (sugar cane production), agricultural pollution related to the use of inputs in the catchment area and marine pollution.

Restoration:
The project involves hydrologically restoring shrimp cages and then working with the local community to reforest the affected areas. It will also study different mangrove species and planting methods.

Mangroves in this region of the north Pacific are restricted to areas that rarely exceed 20 hectares. The structure of these ecosystems is unique in Costa Rica. Historically, salt production was the main cause of the deforestation of the site’s mangroves. Today, however, the only threat to the mangroves appears to be the urbanisation of the Cuajiniquil region.

Restoration:
The former salt marsh to be restored covers an area of approximately 7 hectares. A microtopography analysis will identify the channel network that needs to be created in order to restore the area’s hydrological functions. This water-based restoration project is designed to re-establish the natural flow of the water, which will dilute the salts and restore oxygen to the soil. Today these variables seem to be the main factors limiting the natural regeneration of this former salt marsh.

Between 1980 and 2006, Benin lost a quarter of its mangroves. Most of the coastal mangroves of the Mono River delta, which fall within the scope of RAMSAR sites, are located in the municipalities of Ouidah and Grand Popo. These districts comprise a large number of coastal villages whose activities essentially involve exploiting natural mangrove resources. In the lakeside villages of Ouidah, salt production is the main – and sometimes the only – source of income for the local population, placing enormous pressure on the mangroves. As a result, many areas around these villages have been totally deforested.