Effectiveness of protected areas influenced by socio-economic context

Protected areas (PAs) are not completely halting biodiversity loss, according to growing evidence. This study shows the limited effectiveness of a large network of PAs despite favourable socio-economic context and high conservation efforts, suggesting that PA functional design matters beyond increasing resources. Protected area (PA) performance is thought to depend on effective conservation management and favourable socio-economic context. However, increasing evidence of continued biodiversity decline within PAs raises the question of whether fundamental ecological and socio-economic constraints might actually affect PA effectiveness. Here we quantify how threats to biodiversity, socio-economic context and conservation efforts play out across 114 PAs in 25 European and African countries. We found that even in the presence of highly favourable socio-economic context and conservation efforts, it is not possible to completely offset the intensity of threats and prevent biodiversity decline. Projections show that halting biodiversity decline across the studied PA network may require at least a 35% increase in conservation efforts over a decade. However, as PAs approach zero biodiversity loss, even greater efforts and resources would be needed because of the principle of diminishing marginal returns. Our findings point to limited effectiveness of PAs and their management that might not be possible to address by simply increasing resources. Additionally, the adoption of core design principles of sustainable systems that take into account the social-ecological contexts of PAs could help overcome the observed hurdles of limited effectiveness and thus better integrate PAs into sustainable development efforts.

Automated summary

Despite favorable socio-economic context and high conservation efforts, protected areas have limited effectiveness in halting biodiversity loss. Increasing conservation efforts may be necessary, but the diminishing marginal returns principle implies that even greater efforts and resources would be needed as protected areas approach zero biodiversity loss. Adopting core design principles that consider the social-ecological contexts of protected areas could help overcome the observed hurdles of limited effectiveness and better integrate them into sustainable development efforts.