Unveiling the Dynamic Impact of Protected Areas: An Event Study Analysis to Assess Conservation Effectiveness

Abstract

Previous studies estimating the effect of the creation of protected areas (PAs) on ecosystem conservation suffer from biases due to staggered protection and to unobservable drivers of protection’s effectiveness. We address these biases by using a cohort-time refined effect estimator in an event study with Amazon Basin data from 2003 to 2020. We also unveil meaningful dynamic patterns that remained so far hidden in previous papers’ aggregate effects. Our findings show that PAs’ effect on deforestation was halved by the aforementioned biases, being also deflated in 13% by the failure to control for concomitant anti-deforestation policies. We also found evidence of forward-looking behavior by deforesters, with internal deforestation increasing two years before protection. Effects were also heterogeneous. Whereas both moderately and severely restricted PAs avoided fires, only severely restricted avoided deforestation. Finally, whereas conservation unit PAs have not reduced deforestation, national units reduced fires but subnational increased them. Indigenous lands reduced deforestation and fires.