2008年-世界发展银行全球_Impact_of_Costa_Ricas_Program_of_Payments_for_Environmental_Services_on_Land_Use_25页_1mb

报告摘要

Summary of PES Learning Paper 2008-3: Impact of Costa Rica's Program of Payments for Environmental Services on Land Use

Core Content

This paper evaluates the impact of Costa Rica's Program of Payments for Environmental Services (PSA) on land use, focusing on whether the program has led to an increase in forest conservation. As the only long-term, large-scale PES initiative for tropical forests, the PSA program provides annual payments to landowners who agree to maintain forest cover on their properties. The study aims to determine the causal effect of the program by comparing the land use outcomes of participants and non-participants, using rigorous program evaluation methods.

Main Points

PSA Overview: The program, initiated in 1997, offers payments to landowners for forest conservation, reforestation, and sustainable management. It is designed to provide a direct economic incentive for conservation.
Challenges in Evaluation: Direct comparison of participants and non-participants is problematic due to 'selection bias', as landowners who participate in the program may differ from non-participants in ways that affect land use decisions. This necessitates the use of advanced methods such as propensity score matching to estimate the program's causal impact.
Evaluation Methods: The study employs both geographic pre-matching and propensity score matching. These methods help identify a comparison group of non-participants that is similar to participants in terms of biophysical and market conditions, allowing for a more accurate assessment of the program's impact.
Data and Sampling: The case study is conducted in the Sarapiquí region, where the first phase of the PSA program was implemented. Data is collected from 50 PSA participants and 150 non-participants, including socio-economic and land use characteristics. Remote sensing and GPS data are also used to map land cover changes.

Key Findings

The PSA program has resulted in a small but statistically significant increase in the area of forest conserved.
Selection Bias: Landowners who are more likely to participate in the program tend to have stronger environmental attitudes or less viable agricultural options. This suggests that the observed forest conservation may not be solely due to the payments but also due to pre-existing differences between participants and non-participants.
Non-participation Reasons: Lack of information is the most common reason for non-participation in Sarapiquí, followed by land tenure issues and complexity of the program. In contrast, in Heredia and San José, economic factors and distrust of the system are more significant.
Indirect Impacts: The program may have indirect effects, such as encouraging additional conservation (spill-overs) or deforestation in areas not under contract (leakages). These effects are more likely on partially contracted fincas.
Educational Role: The program has an educational function, as many participants report increased awareness and appreciation of the environmental value of forests.

Conclusion

The study confirms that the PSA program contributes to forest conservation, although the impact is relatively small.
The findings suggest that the program is more effective in areas where landowners have limited agricultural alternatives or strong environmental values. However, the program's success may also depend on the availability of information and the clarity of land tenure rights.
The use of propensity score matching is essential to account for selection bias and to estimate the true causal effect of the program on land use outcomes.

Authors and Funding

The paper is authored by Erin Sills, Rodrigo Arriagada, Paul Ferraro, Subhrendu Pattanayak, Luis Carrasco, Edgar Ortiz, Silvia Cordero, Katie Caldwell, and Kwaw Andam.
The research is funded by the National Science Foundation (SES-0519194) and FONAFIFO (Ecomarkets Project). Additional support is provided by Conservation International and various institutions for data collection and analysis.