Coastal Development

Coastal development may be the primary threat to mangroves. Not only are the forests lost when a coast is developed, but a man-made structure almost always replaces them. That structure (e.g., a hotel, desalination plant, coal-fired power plant, nuclear plant, port facility, marina, cruise ship dock) inevitably brings with it associated issues of altered hydrology, erosion, and pollution. Rivers that once traveled through the mangroves before emptying into the sea are blocked or re-routed, causing changes in filtration, sedimentation, temperature, and salinity. These changes in turn can affect the aquatic species, including commercial or subsistence fish species for coastal communities. The developments are often associated with increased levels of pollution as well, including solid waste, pesticides, thermal, biological (invasive species), brine, and oil. In Panama, for example:

“In recent years the biggest regional threats to mangroves are the ever-increasing development of the tourism industry, pollution from runoff of fertilizers and pesticides, and improper disposal of wastes. Oil pollution is not a widespread problem for the region as a whole, but it is a serious threat in Panama owing to the extremely high maritime traffic in the Panama Canal (Spalding et al. 1997, FAO 2007, p. 34).

In other areas where deepwater ports are built to ship mined ore, natural gas, petroleum, chemicals, coal, and other polluting materials, the chances of an oil spill from boat traffic increased dramatically, as do the chances for a spill of hazardous materials. In short, once a development is built, there is little that can be done to maintain healthy, pollution-free coastal ecosystems. As a result, the benefits of every coastal development project should be carefully weighed against the costs of losing the protective, functioning mangrove systems.