The impact of payment for ecosystem service schemes on participants' motivation: A global assessment

Payment for Ecosystem Services (PES) is a commonly used policy tool to fund nature conservation efforts. However, the implementation of financial incentives may have unintended consequences on intrinsic motivations, such as attitudes and environmental values, resulting in reduced levels of pro-environmental behaviors after PES compared to those observed before PES. The effect of PES schemes on participants' motivations is not well understood. To address this gap, we conducted a quantitative analysis of motivation effects in PES schemes using 155 data points from 126 primary studies. Our study found that: 1) 54% of PES projects had a crowding-in effect, reinforcing intrinsic motivations, while 42% had a crowding-out effect, weakening intrinsic motivations; 2) PES projects with community payments were more likely to induce crowding-out due to free-riding and reduced trust; 3) compliance monitoring was a weak predictor of crowding-in, possibly due to increased satisfaction; and 4) monetary payment, when compared to in-kind payment, was more likely to lead to crowding-out due to reduced autonomy. Our findings also suggest that crowding-in is associated with successful environmental outcomes, while crowding-out is associated with environmental failure. To enhance the effectiveness of PES programs, policymakers should promote motivation crowding-in and prevent crowding-out by using in-kind payments, addressing free-riding, and enhancing fairness and transparency through monitoring, where feasible.