Identification of threatened and resilient mangroves in the Belize Barrier Reef system

BY: EMIL A. CHERRINGTON*, BETZY E. HERNANDEZ, NOEL A. TREJOS, OCTAVIO A. SMITH, ERIC R. ANDERSON, AFRICA I. FLORES, AND BESSY C. GARCIA

Water Center for the Humid Tropics of Latin America and the Caribbean (CATHALAC)

Mangroves are an important component of the Belize Barrier Reef Complex, a mosaic of coral reef, sea grass, and mangrove ecosystems, and the world's second largest barrier reef system. Based on satellite imagery available through the Regional Visualization & Monitoring System (SERVIR), the extent of Belize's mangrove cover was assessed over a 30-year period to obtain a previously unavailable time-series of information on the status of these ecosystems. Using Zisman's (1998) mangrove extent data as a baseline, a multi-temporal remote sensing based change detection study was conducted by performing spectral mixture analysis on Landsat satellite imagery for the years 1980, 1989, 1994, 2000, 2004, and 2010. This assessment indicates that from late 1980 through early 2010, Belize's mangrove cover declined from 188,417 acres (76,250 hectares), or 98.7% of the original extent, to 184,548 acres (74,684 ha.), or 96.7% of the original extent. Those figures equate to a net loss of approximately 3,900 acres of mangrove cover over roughly 30 years, a loss of 2% of the 1980 mangrove cover. The average annual net loss was estimated at 0.07%, or 125 acres. At the scale of 1:100,000, this assessment also reveals that land clearing resulted in fragmentation of some 2.1% of mangrove communities. In terms of the resilience of mangrove ecosystems, a mere 236 acres (96 ha.) of the area cleared between 1980 and 2010 was detected to have regrown. It is also assumed that widespread mangrove regrowth was likely not seen because land previously occupied by mangroves is permanently converted to other land uses such as infrastructure for housing. Whereas recent publications such as the 2010 World Mangrove Atlas indicate that a fifth of the world's mangrove cover had been lost since 1980, the loss of 2% of Belize's overall mangrove cover between 1980 and 2010 can be considered low.

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