作为联系生态系统服务提供者和受益者、整合生态保护与经济社会发展的有效途径,生态补偿在全球范围内得到广泛应用,但目前对生态系统服务供给者、受益者的成本效益以及生态系统服务供给者生计变化关注很少,影响着生态补偿项目的公平性与效率。尤其是生态补偿项目参与者受到补偿后的生计变化,可能通过影响区域经济结构和自然资本而最终改变项目的总体效果和可持续性。中国科学院生态环境研究中心欧阳志云研究员的研究团队和美国斯坦福大学Gretchen Daily教授、美国明尼苏达大学Stephen Polasky教授合作,以2006年北京市和河北承德、张家口地区联合在密云水库流域实施的生态补偿项目——“稻改旱”工程为例,评估了该项目的成本、效益及对农户生计的影响。
研究发现:“稻改旱”项目是一个成功的生态补偿项目,“稻改旱”项目的成本效益比为1:1.5,生态系统服务供给者和受益者的成本效益比分别为1:1.2和1:1.3,通过下游给上游地区经济补偿,促进上游地区土地利用改变,进而促进水质和水量改善。但项目实施后,农户生计资本与生计活动也发生了两方面的显著变化,一方面,项目参与农户家庭收入、打工收入、教育投入和物质资本显著增加,农业用工显著减少、薪柴使用也呈减少趋势,生计资本和活动的这些变化有助于农户生计和流域生态环境改善;另一方面,项目参与农户农药、化肥投入显著增加。尽管因土地利用的变化而导致养分保持的净效益是正的,但农药、化肥投入的增加部分抵消了项目的预期目标,并将会对地下水污染等带来潜在风险。从长远角度,这将产生不利的环境影响。
该研究为整合了农户生计变化开展生态补偿研究提供了框架,项目评估揭示了生态补偿项目实施如何导致农户生计活动发生有利的或不利的环境后果,强调了生态补偿项目中考虑项目参与者行为变化的重要性,这在今后的生态补偿项目设计、评估、农户生计与环境研究中具有重要的政策和方法应用。生态补偿项目政策设计者应该仔细考虑合适的机制促进长期的、有利的环境和生计后果,避免或减小可能的不利影响。
该成果在线发表在国际著名综合性期刊Proceedings of the National Academy of Sciences上,该研究得到国家自然科学基金、城市与区域生态国家重点实验室自主项目等资助。
生物谷推荐英文摘要:
PNAS doi:10.1073/pnas.1312324110
Benefits, costs, and livelihood implications of a regional payment for ecosystem service program
Hua Zhenga,1, Brian E. Robinsonb,c,1, Yi-Cheng Liangc, Stephen Polaskyb,c,d, Dong-Chun Mae, Feng-Chun Wange, Mary Ruckelshausc, Zhi-Yun Ouyanga,2, and Gretchen C. Dailyc,f,2
Despite broad interest in using payment for ecosystem services to promote changes in the use of natural capital, there are few expost assessments of impacts of payment for ecosystem services programs on ecosystem service provision, program cost, and changes in livelihoods resulting from program participation. In this paper, we evaluate the Paddy Land-to-Dry Land (PLDL) program in Beijing, China, and associated changes in service providers’ livelihood activities. The PLDL is a land use conversion program that aims to protect water quality and quantity for the only surface water reservoir that serves Beijing, China’s capital city with nearly 20 million residents. Our analysis integrates hydrologic data with household survey data and shows that the PLDL generates benefits of improved water quantity and quality that exceed the costs of reduced agricultural output. The PLDL has an overall benefit–cost ratio of 1.5, and both downstream beneficiaries and upstream providers gain from the program. Household data show that changes in livelihood activities may offset some of the desired effects of the program through increased expenditures on agricultural fertilizers. Overall, however, reductions in fertilizer leaching from land use change dominate so that the program still has a positive net impact on water quality. This program is a successful example of water users paying upstream landholders to improve water quantity and quality through land use change. Program evaluation also highlights the importance of considering behavioral changes by program participants.