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Ecological Integrity refers to the ability of an ecosystem to support and maintain ecological processes and a diverse community of organisms. Ecological Integrity is measured as the degree to which a diverse community of native organisms is maintained, and is used as a proxy for ecological resilience, intended as the capacity of an ecosystem to adapt in the face of stressors, while maintaining the functions of interest.

For example, the presence of a diverse portfolio of species increases the probability that at least some of these species have the traits required to survive and maintain a suite of ecosystem functions in the face of climate change. Such is the case for an intact coral reef system that can better withstand the effects of ocean acidification than an impacted reef, while maintaining functions such as productivity.

How Was It Measured?

The Ocean Health Index measured Ecological Integrity as the relative condition of assessed species in a given location. This was calculated as the weighted sum of the International Union for Conservation of Nature’s (IUCN) assessments of species.  Weights used were based on the level of extinction risk following Butchart et al. 2007: EX (extinct) = 0.0, CR (critically endangered) = 0.2, EN (endangered) = 0.5, VU (vulnerable) = 0.7, NT (not threatened) = 0.9, and LC (least concern) = 0.99. For primarily coastal goals, the spatial average of these per-pixel scores was based on a 3nmi buffer; for goals derived from all ocean waters, the spatial average was computed for the entire EEZ.  

IUCN periodically reports the results of assessments of new species and the Ocean Health Index incorporates the latest information available. Newly reported population trends produced by IUCN for more than 1,300 species were added in 2013 and approximately 1,500 species were added for 2015. 

Ecological Integrity is a Resilience measure used in calculating scores for five of the Goals. The Goals that it influences are Food Provision (Fishing), Artisanal Fishing Opportunity, Natural Products, Sense of Place (Iconic Species), and Biodiversity (all subgoals except Species).  


Andreasen, J. (2001). Considerations for the development of a terrestrial index of ecological integrity. Ecological Indicators 1, 21–35.

Karr, J. R. (1993). Defining and assessing ecological integrity: Beyond water quality. Environmental Toxicology and Chemistry 12, 1521–1531.

Parrish, J. D., D.P. Braun and R.S. Unnasch. (2003). Are we conserving what we say we are? Measuring ecological integrity within protected areas. Bioscience 53, 851–860.