Coral Reef Mapping

Coral reefs are among the most spectacular and diverse of all marine ecosystems. Frequently described as the rainforests of the sea, they are also of considerable social and economic value. Reefs are an important resource-base for a wide range of artisanal and commercial fisheries, supplying the major protein source for millions of people. The value of reefs for attracting coastal tourism is a relatively new development, but is growing at unprecedented rates, providing employment and crucial economic support in many developing countries. Reefs also serve as important buffer against coastal erosion and damage from tropical storms.

Reefs are increasingly threatened by the activities of man. Overfishing and destructive fishing practices are threatening the functioning of reef ecosystems and even the fabric of the reefs themselves. Development has often led to land reclamation on reefs and damage to other areas by pollution and eutrophication. Deforestation and poor agricultural practices, often many miles from the coast are further responsible for heavy sedimentation which can smother and kill wide areas of reefs.

Despite the importance of reefs, and the apparently widespread threats to their existence, there remain considerable gaps in our knowledge about reefs. We are still hampered by a lack of information on the distribution and status of these ecosystems, while the exact pattern and extent of these threats remains unclear.

UNEP-WCMC and Coral Reefs
In the 1980s, with support from the United Nations Environment Programme and IUCN-The World Conservation Union, UNEP-WCMC compiled the three-volume Coral Reefs of the World. This work represented a landmark publication in developing our understanding of the distribution and status of coral reefs, and remains a unique and highly acclaimed reference work.

Since 1993, UNEP-WCMC has been collaborating with the International Center for Living Aquatic Resources Management (ICLARM) in the Philippines in the development of a global encyclopedic database on coral reefs. The first version of this database, ReefBase, was released as a CD- ROM in 1996. Annual releases will continue to provide updates and major revisions to this database. UNEP-WCMC's role in the development of ReefBase has been the preparation of a global map of coral reefs. Using the Protected Areas Database at UNEP-WCMC it has also been possible to identify over 350 protected areas worldwide which incorporate coral reef habitats.

Why map coral reefs?
There have been few systematic global surveys of coral reefs since the efforts of Charles Darwin in 1842 and the work of Joubin early this century. The only widely accepted summary statistics on reef coverage were published by Smith in 1978. There is a growing need for recent, accurate information describing coral reefs for use by aid agencies, conservation organisations and industry as well as individual scientists and the public in monitoring, planning operations and investment, predicting fisheries statistics, planning shipping routes, scientific research, conservation and education. ReefBase is already being used for many of these purposes, but by holding the maps on the Biodiversity Map Library at UNEP-WCMC, the data are available for wider distribution and also being used in the preparation of other publications and educational materials, in providing information to industry and conservation agencies, in support of oil-spill contingency planning and emergency response, and in primary scientific research.

Reef Maps - features to be incorporated
Although the primary focus has been to map the reefs themselves, attempts are being made to develop a much wider information base, including other related habitats and physical features. The following is a list of features held at UNEP-WCMC for some countries, but which are also seen as important for future data gathering efforts.

Physical features: Coastline, differentiated if available, into mud, sand/gravel, rock, cliffs etc.; bathymetric data, 20, 50 and/or 100m wherever available; simple wind, tide and current data.

Substrate/habitat: Coral Reefs (emergent reef crest, and reef areas as polygons where available); mangroves; seagrasses.

Species: Turtle feeding and nesting sites; reef fish distribution; hermatypic coral genera and species distributions; sirenian (dugong and manatee) distribution; seabird colonies.

Human aspects: Protected areas; fisheries data; shipping channels; research stations; dive sites; towns and cities; tourist and fishing centres; other planning regimes (shipping, fishing, controls).