Gef-iw5 etps mangroves

SECTION 3: PROJECT JUSTIFICATION

1. Problem Definition: Global Environmental Problems and Root Causes

Despite the importance of mangroves to the ETPS, these ecosystems have been subject to extensive loss and degradation. Regional rates of loss are similar to those in coastal regions globally; over the past 50 years approximately one-third of the world’s mangrove forests have been lost with continuing losses estimated at 1-2% annually. In fact, the highest proportion of threatened mangrove species is found along the coasts of Central America, with 40% of the mangrove species present along the Pacific coasts of Costa Rica, Panama and Colombia listed as threatened, with one species Rhizophora samoensis IUCN red listed as Near Threatened (Polidoro et. al. 2010).

Root causes of mangrove habitat loss in the ETPS are linked to rapid and largely unregulated urban expansion in coastal areas with new in-roads to the coast and commercialization for coastal markets. In particular the expansion of shrimp aquaculture from the 1970s' displaced large areas of mangrove. This outpaced the capacity of resource managers to effectively respond. Hence policy that tackled emerging issues linked to better environmental awareness and corporate social responsibility was limited until the late 1990s.

1. Coastal development.

Each of the ETPS countries’ largest coastal cities is located in large gulfs with extensive mangrove formations and each of these cities - Guayaquil (Ecuador), Buenaventura (Colombia), Panama City (Panama), and Puntarenas (Costa Rica) - have expansively grown in recent decades as important commercial ports and regional transport hubs. Consequently mangrove loss and degradation has been increasingly driven by urban expansion, associated industrial and shipping activities, and the waste produced by large coastal populations with inadequate sewage and garbage management infrastructure.

Major direct impacts include drainage of coastal wetlands, deforestation and reclamation, and discharge of sewage, fertilizers and contaminants into coastal waters. Engineering structures, such as damming, channeling and diversions of coastal waterways, harden the coast, change circulation patterns and alter freshwater, sediment and nutrient delivery. Natural systems are often directly or indirectly altered, even by soft engineering solutions, such as beach nourishment and fore-dune construction (Nordstrom, 2000; Hamm and Stive, 2002). Ecosystem services on the coast are often disrupted by human activities designed to resolve erosion problems after natural barriers such as mangroves are lost.

2. Aquaculture and agriculture.

Rapid expansion of aquaculture has also resulted in extensive deforestation in the ETPS from conversion of mangrove forest to shrimp ponds. For example, in the two decades starting in 1980, nearly half of the mangrove area of Ecuador (~80,000 ha) was deforested for various purposes, but particularly for shrimp ponds. Shrimp ponds are the major cause of mangrove decline in Latin America (Lugo 2002). At local levels loss continues. Examples include David (Panama) where despite a small population (around 130 people across 21 settled areas in mangrove protected areas) there was a 21% loss in mangrove from 1979-2004 (Cathalac 2008).

In more rural areas, agricultural expansion replaced mangrove forest with land of marginal value for livestock grazing and rice production. In Costa Rica’s Gulf of Nicoya the expansion of rice production has been a leading cause of mangrove loss and in Panama’s Gulf of Chiriquí region the expansion of marginal grazing lands has encroached into coastal mangrove forests.

3. Overexploitation of wood products.

Significant additional mangrove losses in the region have resulted from exploitation for wood products. Charcoal production is a significant source of mangrove degradation and loss in the region. In Costa Rica up to 1,300 m³ of mangrove charcoal is produced annually, while in Panama this may reach up to 7,400 m³. Mangrove bark is a source of tannins for the leather industry in most Latin America countries. Bark yields range from 1,840 to 4,490 kg/ha in Costa Rica, and total production may reach over 400 tons/year in Panama (Lacerda et al 1993). The need for tannins is the leading cause of mangrove degradation in Panama’s Gulf of Chiriquí where local communities have not yet adopted tannin substitutes for the local leather processing industry. In Colombia’s Gulf of Tortugas direct exploitation for firewood and the need for construction materials is a leading cause for mangrove loss.

4. Alteration of important “ridge-to-reef” processes:

Apart from direct deforestation itself, degradation of large mangrove areas in the ETPS is being driven by inappropriate land-use practice in upstream watersheds. Diversion of freshwater for irrigation, application of pesticides and herbicides in agricultural lands and farming on steep slopes leading to high erosion rates are major causes of mangrove degradation in the region (Conde & Alarcon, 1993) and in many cases the result of inadequate knowledge of impacts on the surrounding system and limited EIA assessments.

Major direct impacts include drainage of coastal wetlands, deforestation and reclamation, and discharge of sewage, fertilizers and contaminants into coastal waters. Engineering structures, such as damming, channeling and diversions of coastal waterways, harden the coast, change circulation patterns and alter freshwater, sediment and nutrient delivery. Natural systems are often directly or indirectly altered, even by soft engineering solutions, such as beach nourishment and fore-dune construction (Nordstrom, 2000; Hamm and Stive, 2002). Ecosystem services on the coast are often disrupted by human activities designed to resolve erosion problems after natural barriers such as mangroves are lost.

5. Global Climate Change:

Often referred to as "blue carbon" ecosystems alongside salt marshes and seagrasses, mangroves can have a carbon sequestration rate of over 65 kg/ km² each year resulting in an estimated 20,000 kg /km² of carbon sequestered in soils. As new methodologies are developed to estimate carbon sequestration through mangrove production and the consolidation of carbon enriched soils it becomes evident that mangroves have a greater role influencing global carbon cycle than previously thought. Hence the impact of significant mangrove degradation in the region in the last 40 years and continued persistent losses likely implies a sizeable and accumulated carbon footprint of consequence to global economies. Carbon storage reconstructions for mangroves in Ecuador for example show a 47% nationwide loss between the 1970-1990 period due mostly to deforestation for shrimp farms (Hamilton & Lovette, 2015).