Reefs at Risk: A Map-Based Indicator of Threats to the World's Coral Reefs

In many communities around the globe coral reefs are a vital source of food, a draw for much needed tourist dollars, and a protective buffer for vulnerable coastlines. They are also some of the most ancient and biologically diverse ecosystems on the planet. In fact, though they occupy less than one quarter of 1 percent of the earth’s marine environment, they are home to more than a quarter of all known marine fish species. These habitats have been called the “rainforests of the sea”: highly productive, rich in species, and – because they are predominantly located in many regions noted for extreme poverty and high population growth rates – particularly vulnerable to future degradation.

Reefs at Risk: A Map-Based Indicator of Threats to the World’s Coral Reefs, produced by the World Resources Institute (WRI) in collaboration with the WorldFish Center (formerly ICLARM), the World Conservation Monitoring Centre (WCMC), and the United Nations Environment Programme (UNEP), is the first global assessment of coral reefs to map areas at risk from overfishing, coastal development, and other human activity.

The study finds that nearly 60 percent of the earth’s coral reefs are threatened by human activity – ranging from coastal development and overfishing to inland and marine pollution – leaving much of the world’s marine biodiversity at risk. In addition, the report concludes that while reefs provide billions of people and hundreds of countries with food, tourism revenue, coastal protection and new medications for increasingly drug-resistant diseases – worth about $375 billion each year – they are among the least monitored and protected natural habitats in the world.

Key findings of the report include:

• Coral reefs of Southeast Asia, the most species-rich on earth, are the most threatened of any region. More than 80 percent are at risk, primarily from coastal development and fishing- related pressures.

• Most United States reefs are threatened. Almost all the reefs off the Florida coast are at risk from a range of factors, including runoff of fertilizers and pollutants from farms and coastal development. Close to half of Hawaii’s reefs are threatened, while virtually all of Puerto Rico’s reefs are at risk.

• Nearly two-thirds of Caribbean reefs are in jeopardy. Most of the reefs on the Antilles chain, including the islands of Jamaica, Barbados, Dominica and other vacation favorites, are at high risk. Reefs off Jamaica, for example, have been ravaged as a result of overfishing and pollution. Many resemble graveyards, algae-covered and depleted of fish.

But the news is not all bad. The report also describes steps that can be taken to combat threats to coral reefs, and includes the stories of communities around the globe that have successfully addressed these challenges to their marine environment and way of life.

Reefs at Risk concludes that the most important actions for promoting healthy coral reef ecosystems depend largely on these efforts by local governments, community groups, environmental organizations and the private sector. Many are win-win solutions: creating marine parks that, in turn, create new jobs; treating sewage before it reaches reefs (which benefits human health); and eliminating costly government subsidies. A well-managed marine protected areas system is one of the most effective approaches for assuring healthy reefs, while generating tourism dollars and maintaining the vitality of nearby fisheries.

As Sylvia A. Earle, Explorer-in-Residence at the National Geographic Society, writes in the foreword to Reefs at Risk, “The fate of coral reefs, the ocean, and humankind forty years from now and forevermore will depend on the intelligence, motivation, and caring of people now alive. In that spirit, this report provides hope that we may succeed.”

Financial Support

• Bay Foundation
• Henry Foundation
• David & Lucile Packard Foundation
• Swedish International Development Cooperation Agency
• United Nations Environment Programme
• United States Environmental Protection Agency

Project Partners

• UNEP World Conservation Monitoring Centre
• WorldFish Center (formerly International Center for Living Aquatic Resources Management)

GIS Data Sets

• Global Data: ArcView Shapefile Format (ZIP archive, 681 Kb). Geographic Projection. This archive ncludes four files: a data documentation file, and three files which together comprise the ArcView Shapefile called reef_pts. These three files have .dbf, .shp, and .shx extensions. These data will unzip into a directory called \reef_wri\data_geo\.

• Global Data: Raster (GRID) Format (ZIP archive, 2.3 Mb). Mercator projection, at 4 kilometer resolution. This archive includes a data documentation file; coral reefs classified by threat from human activity in ArcInfo GRID format; four data sets in GRID format which represent estimated threats from Coastal Development, Marine-based Pollution, Overexploitation of Marine Resources, and Pollution and Sediment from Inland Activities, respectively; one data set in GRID format which summarizes our estimate of threat from the four categories of human activities; one ArcView Shapefile data set reflecting coral reefs classified by threat from human activity in point format for comparison (same data as in reef_pts.zip; and one ArcView project file to make the mapping of these many datasets easier.

Notes on unzipping

For the GRID data to work, it is important that the data retain the directory (path) structure that they were saved with. This happens automatically with the WinZip Software. If using PKUNZIP, it is important to use the “-d” option of the command. These data should unzip into a directory called \reef_wri\data_mer\. For the ArcView project to correctly reference the data locations, it is best to unzip these data onto the c:\drive.