Balancing efficiency and equity in regional and national pathways towards 30 × 30 in the Insular Caribbean

Global and local biodiversity decline is prompting increased targets for protected area designation, including the Global Biodiversity Framework's target of 30% protection by 2030. As nations look to expand protected area portfolios, regional approaches are often regarded as the most efficient pathway. However, prioritising regional coordination over national-level planning can undermine equity between countries. Here, we assess the efficiency and equity considerations of national and regional-scale approaches in the Insular Caribbean, utilising the systematic conservation planning tool, Marxan.

We represented biodiversity with 343 habitat classes spanning terrestrial, freshwater, and marine realms across over 3 million square kilometres and 29 political jurisdictions. At the time of analysis, baseline regional protection, covering 19% of land and 10% of marine areas, was sufficient to meet representation targets for only 37 of 90 terrestrial classes, 18 of 72 freshwater classes, and 23 of 81 marine classes. To close these gaps, we developed expanded reserve network solutions that achieved 30% coverage for all habitats, and compared results from a fully collaborative, regional solution against those from a nationally-stratified solution.

We found that a regional approach offers the most cost-effective pathway, significantly reducing financial burden on individual nations. However, this approach creates inequities as conservation burdens and benefits are unevenly distributed, resulting in higher cost for some countries and complete exclusion for others. We conclude that both regional and national pathways to conservation can be complementary, allowing a flexible approach to protected area designation, and this multi-scale approach provides a transferable model for other regions.