Agent based modeling of payments for ecosystem services in Costa Rica – Adoption, dynamics and sustainability of silvopastoral practices

在拉丁美洲的永久牧场上养牛引起了人们对生物多样性丧失、温室气体排放增加和碳固存减少的长期关切。过去，牧场生产力的下降导致了大规模的森林砍伐。生态系统服务付费被确定为一种基于市场的机制，以激励重新造林和保护林区。在这里，服务提供者因产生积极的外部效应而由服务使用者支付报酬。然而，林业的土地专用限制了土地所有者，降低了他们从农业生产中创收的能力。人们发现，林牧做法既增加了现场效益，也增加了场外效益。在牧场种植树木和灌木物种减少了侵蚀，增加了生物多样性和碳固存。当地的好处是，例如，改善牧场，由于树荫、木材、饲料和收入多样化而提高牲畜生产力。哥斯达黎加、尼加拉瓜和哥伦比亚率先实施了第一个森林畜牧业生态系统服务补偿方案。2002年至2007年期间实施了区域综合森林牧场生态系统管理项目，该项目被认为是一个巨大的成功，因为它导致了12000多公顷的牧场，改善了生物多样性和碳固存。然而，人们对该方案的可持续性仍有疑问，因为它需要支付有限的款项，这被假设为“打破平衡”。研究提案的第一个目标是阐明哥斯达黎加为森林牧场收养支付的可持续性。直到现在，在停止付款十年后，才能看到生长缓慢的树木和灌木物种产生的全部效益。生态系统服务提供者的长期采用状态也是如此。第一个目标将通过住户调查来实现，以补充二手数据。在项目期间和项目结束后收集的数据将允许调查随着时间的推移采用状态和保护强度。第二个目标是确定采用技术的过程。最近的研究强调，非货币驱动因素和沟通途径对采用至关重要。也就是说，规范、有限理性模型和在社交网络中的地位与货币激励相互作用。基于代理的模型已经证明了它们复制后者的能力。因此，第二个目标将接近的发展和分析的代理人为基础的模式，生态系统服务费用补偿采用森林畜牧业的做法。在这里，将通过模拟模型研究支付水平、保护强度和长期可持续性之间的比率。 这些比率将在农场结构和社会嵌入性发生变化的情况下进行测试。此外，不同的社会网络拓扑结构的分析将有助于理论的发展。该模型将使用经验数据进行参数化。

Cattle production on permanent pastures in Latin America causes prolonged concerns with respect to losses in biodiversity, increased greenhouse gas emissions and reduced carbon sequestration. Decreasing pasture productivity has led to massive deforestation in the past. Payments for ecosystem services (PES) have been identified as a market based mechanism to incentivize reforestation and conservation of forest areas. Here, service providers are paid by service users for producing positive externalities. However, the exclusive land use of forestry constraints land owners and reduces their ability to generate income from agricultural production. Silvopastoral practices have been found to increase both; on-site and off-site benefits. The inclusion of tree and shrub species in the rangelands reduces erosion, increases biodiversity and carbon sequestration. On-site benefits are e.g. improved pasture, increased livestock productivity due to shade, timber, fodder and income diversification. Costa Rica, Nicaracua and Colombia pioneered the first PES program for silvopastoral practices. The Regional Integrated Silvopastoral Ecosystem Management Project (RISEMP) was implemented between 2002 and 2007 and was considered a huge success as it resulted in over 12000 ha of pastures with improved biodiversity and carbon sequestration. However, doubts remain on the sustainability of the program as it entailed finite payments which were hypothesized to “tip the balance”. The first objective of the research proposal is to elucidate the sustainability of payments made for silvopastoral adoption in Costa Rica. Only now, ten years after payments have ceased, the full scope of benefits arising from slow growing tree and shrub species is observable. The same accounts for the long-term adoption state of ecosystem service providers. The first objective will be approached with a household survey complementing secondary data. Data gathered during, and right after the end of the project, will allow investigating adoption states and conservation intensity over time. The second objective is the identification of processes of technology adoption. Recent studies emphasize that non-monetary drivers and communication pathways matter for adoption. That is, norms, models of bounded rationality and the position in social networks interact with monetary incentives. Agent based models have proven their ability to replicate the latter. Thus, the second objective will be approached by the development and analysis of an agent based model of PES adoption of silvopastoral practices. Here, the ratios between payment levels, conservation intensity and long-term sustainability will be investigated by the simulation model. The ratios will be tested in scenarios of a shift in farm structure and social embededdness. Moreover, the analysis of different social network topologies will contribute to theory development. The model will be parameterized with empirical data.