Role of habitat definition on Aichi Target 11: Examples from New Caledonian coral reefs

Abstract

The Aichi 2020 Biodiversity Targets are the backbone of many conservation projects. As the 2020 deadline is approaching, countries assess their progress. Target 11 (ABT11) calls for the protection of at least 10% of coastal and marine areas, while encouraging to focus on areas with particularly important habitats, notably for coral reefs. This target indirectly poses the question of the definition of habitats and their level of representation in Marine Protected Areas (MPAs). We hypothesized that success or failure in achieving the targets could depend on how habitats are defined and considered. To address this issue, the current level of protection with respect to ABT11 is quantified for a hierarchical inventory of coral reef habitats in New Caledonia, a country with complex governance and diverse coral reefs. At the country scale, ABT11 is met with respect to broadly-defined coral reefs due to the presence of large MPAs. However, reserves are too spatially limited to comply with ABT11 at the provincial scale. The results appear dependent upon the hierarchical level of precision used to define habitats. While reefs as a whole meet Target 11, specific habitats, defined at a more detailed description levels, have varying levels of protection; and some do not meet ABT11. The results highlight that assessments of the achievement of the 11th Aichi target strongly depend upon spatial scales and habitat classification, at least for coral reefs. The findings suggest that Aichi compliance assessments worldwide need to take into account variability and biases linked to habitat description.