Mangrove forests encompass those areas that include some species of mangrove trees and are intertidal tropical and subtropical coastal wetlands. Despite being among the most productive ecosystems in the world, the area of mangrove forests has been globally declining to less than half the former area from the beginning of the 20th century (Field et al., 1998). These trends are due to conversion for agriculture, forestry, and urban uses, and to extraction of timber for fuel and other uses (Farnsworth and Ellison, 1997).