Losses of terrestrial tropical forests have justifiably received much attention recently. By the end of the 20th century, human activities converted up to 30% of the original pristine acreage of terrestrial tropical forests to other land covers (Houghton 1995). Estimates by the Food and Agriculture Organization of the United Nations (FAO 1997) suggest that 1.54×107 ha y–1 of terrestrial tropical forest were lost during the 1980s, and 1.37×107 ha y–1 during 1990–1995. These losses translate into an annual loss of 0.8% of the area of terrestrial tropical forests. Losses of coral reefs have also received considerable press and scientific attention. Best estimates are that about 10% of the world's coral reefs have been lost and perhaps up to 30% will be degraded in 10–20 years (Wilkinson 1992).
For comparison, the world's area of mangrove forests has been reduced by about 35% on a worldwide scale since the 1980s, and 2.1% of the existing worldwide mangrove area is lost each year. The rate is as high as 3.6% in the Americas (Table 2). Such losses of mangrove forests are alarming rates of loss of a major coastal environment.
These comparisons speak to the enormous pressures being exerted on tropical environments by anthropogenic processes. The losses of rain forests and reefs are, rightly, widely acknowledged, and a measure of concern and response to the changes has been manifested. The information compiled here supports the alarm felt by those in the research and management communities with firsthand knowledge of what is happening in the boundary between land and sea, where mangroves grow. Although mangrove forests, especially in the Americas and Asia, are among the most threatened major environments on earth, this major transformation in the coastal tropics has received scant public or political recognition. Comprehensive research aimed at assessing the status of mangroves in many countries must be undertaken, as must restoration or conservation efforts that impel public and political notice of the dimensions of the problem. Although the data reviewed in this article are in many ways incomplete, they do demonstrate the significant global losses of mangrove forests and suggest the need for conservation of this valuable coastal environment.