Comparative Analysis Of Biodiversity Conservation Outcomes In Mpas Versus Non-Protected Marine Areas

Abstract

Marine Protected Areas (MPAs) are universally accepted as fundamental instruments for the protection of marine biodiversity, but their effectiveness is different in ecological and management contexts. This research compares the ecological effects of MPAs to non-protected areas of the sea across various tropical ecoregions. The main objective is to test whether MPAs have greater biodiversity and ecosystem function than ecologically comparable non-MPA sites. This study also explores the extent to which MPA characteristics such as age, protection, and level of enforcement affect conservation effectiveness. Field data were obtained from 16 reef locations (eight MPAs and eight paired non-MPAs) in the Coral Triangle, Western Indian Ocean, Tropical Eastern Pacific, and Caribbean Basin. Underwater visual census, environmental Deoxyribonucleic Acid (DNA) sampling, and remote sensing provided measurements of species richness, fish biomass, trophic composition, coral cover, and functional diversity. Statistical analysis involved Permutational Multivariate Analysis of Variance (PERMANOVA), Non-metric Multidimensional Scaling (NMDS), and generalized linear mixed models. MPAs always maintained greater biodiversity, with average species richness and fish biomass that were significantly greater than those from non-MPAs. Functional richness and dispersion were also greater in MPAs, suggesting greater ecological functions and resilience. Older strictly protected MPAs showed the most robust conservation benefits, whereas partially protected or younger MPAs showed limited gains. MPAs increase biodiversity and ecosystem organization when properly managed. Effectiveness is time since establishment and enforcement quality dependent. These results affirm the necessity of science-informed MPA expansion policies that focus on governance capacity and ecological surveillance.