Experimental evidence on payments for forest commons conservation

Payments for Ecosystem Services (PES) represent a popular strategy for environmental protection, and tropical forest conservation in particular. Little is known, however, about their effectiveness. Many argue that even if PES increase conservation while payments last, they may adversely affect other motivations for pro-environmental behaviour in the longer term. We test whether conditional payments also encourage forest users to conserve shared forest resources after payments end. Using a framed field experiment with 1,200 tropical forest users in five countries, we show that (1) during the intervention, conditional payments increased conservation behaviour; (2) after payments stopped, users continued to conserve more on average than they did before the intervention, especially when they were able to communicate with each other; and (3) trust amplified the lasting conservation effects of the interventions. PES effectiveness may increase when interventions facilitate interpersonal communication and when implemented in contexts where forest users enjoy high levels of trust.