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Why Are Habitats Important?

The Habitats subgoal measures the conservation status of six habitats - mangroves, coral reefs, seagrass beds, salt marshes, sea ice, and subtidal soft-bottom habitats - that are particularly important in supporting large numbers of marine species. This is assessed as the current habitat extent or condition compared to its health in the 1980s.  Global data are not yet available to measure the status of many other important habitats.

All habitats measured contribute equally to the score, regardless of their extent, because the presence of a diverse set of habitats, as well as the level of conservation of each, is considered valuable to achieve this goal. 

Goal Score

91 The goal score for Sub-Goal: Habitats is 91 out of 100. The global average score is 71 out of 100.

Likely Future State


It is estimated that in the near future the score for Sub-Goal: Habitats will improve roughly +5%.
global score


What Does This Score Mean?

The reference point for the status of a country’s diversity-supporting habitats is that their areas or conditions equal or exceed what they were in the early 1980’s. Regions are not penalized for the absence of habitats that do not naturally occur there.

Current Score
The current score indicates that the six habitats assessed- mangroves, coral reefs, seagrass beds, salt marshes, sea ice, and subtidal soft-bottom habitats- are still relatively healthy and intact on a global basis. However, the condition of the assessed habitats has declined over time. Continued decline in the future would undermine the score for Biodiversity and impact many other aspects of ocean health.

This sub-goal score contrasts with numerous scientific studies and media reports. The most important reason is the reference point used in the Ocean Health Index. There is no question that the extent of mangrove forests, salt marshes and seagrass beds have declined considerably compared to historic levels; that sea ice is steadily declining (especially in the Arctic) and that a number of pressures now seriously challenge coral reefs. Since it is not possible to return the ocean to pre-human or pre-industrial age conditions, the reference point for extent or condition of most of these habitats has been set at ~1980, a target that is achievable. Changes that have occurred since then are significant, but not as dramatic as when compared to conditions hundreds of years ago.

More Information


Burke, L., K. Reytar, A. Perry and M. Spalding, (2012). Reefs at Risk Revisited. World Resources Institute: Washington D.C. 
Nature Conservancy

Veron, J. E. N. et al. (2009). Delineating the Coral Triangle. Galaxea, Journal of Coral Reef Studies 11, 91–100.

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