Abstract Payments for ecosystem services (PES) are considered an important policy tool for promoting forest conservation and restoration. The effectiveness of PES programs is typically evaluated by their capacity to reduce deforestation within and around parcels receiving these payments. Larger, landscape-scale, impacts of these programs on processes such as forest fragmentation and connectivity, and payment thresholds that could influence PES effectiveness and their role in regional conservation efforts, remain largely unexplored. Working in three regions with active programs making payments for hydrological services (PHS) in Veracruz state, Mexico, we used a mobile window analysis to identify and compare particular landscapes receiving PHS to similar landscapes not receiving PHS. Difference-in-difference techniques were used to evaluate: 1) changes in metrics of PHS program effectiveness, including deforestation and additionality, in landscapes with low-PHS and high-PHS payment densities; and 2) landscape-scale metrics of ecological integrity, including the capacity of PHS to foster landscapes with less fragmentation and higher connectivity. Maps of forest coverage immediately prior to (1993−2003), and following (2003–2013) the first ten years of, PHS program operation were used to document and compare trends in these areas. Our results suggest PHS significantly reduced deforestation rates but was limited in achieving higher additionality by enrolling mostly areas of lower deforestation risk (only 44 % of PHS occurred in areas of high or very high risk). PHS was not successful in slowing forest fragmentation or the loss of connectivity in our study regions. However, we found that the effectiveness of PHS programs was linked with payment density, with higher PHS coverages resulting in significantly greater reductions in deforestation (41.26 % more effective) vs low-PHS areas. Our findings suggest that measuring PES impact as a change in forest cover alone may over-simplify analyses of the effectiveness of these programs. Overall, a landscape-scale focus appears warranted in PES program design and evaluations of their effectiveness.

中文翻译：

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评估墨西哥韦拉克鲁斯州水文服务付费的环境有效性：景观方法

摘要 生态系统服务付费（PES）被认为是促进森林保护和恢复的重要政策工具。PES 计划的有效性通常通过其减少收到这些付款的包裹内部和周围森林砍伐的能力来评估。这些计划在更大的景观范围内对森林破碎化和连通性等过程的影响，以及可能影响 PES 有效性及其在区域保护工作中的作用的支付门槛，在很大程度上仍未得到探索。我们在墨西哥韦拉克鲁斯州的三个地区开展了积极的水文服务 (PHS) 支付计划，我们使用移动窗口分析来识别和比较接受 PHS 的特定景观与未接受 PHS 的类似景观。差异中的差异技术用于评估：1) 在低 PHS 和高 PHS 支付密度的环境中，PHS 计划有效性指标的变化，包括森林砍伐和额外性；2) 生态完整性的景观尺度指标，包括 PHS 培育具有更少碎片化和更高连通性的景观的能力。使用 PHS 计划运行之前（1993-2003 年）和之后（2003-2013 年）的森林覆盖图来记录和比较这些地区的趋势。我们的结果表明，PHS 显着降低了森林砍伐率，但在实现更高的额外性方面受到限制，因为它主要纳入了森林砍伐风险较低的地区（只有 44% 的 PHS 发生在高风险或极高风险地区）。PHS 未能成功减缓我们研究区域的森林破碎化或连通性丧失。然而，我们发现 PHS 计划的有效性与支付密度有关，与低 PHS 地区相比，PHS 覆盖率越高，森林砍伐的减少幅度越大（效率提高 41.26%）。我们的研究结果表明，仅将 PES 影响作为森林覆盖的变化来衡量可能会过度简化对这些计划有效性的分析。总体而言，在 PES 计划设计和对其有效性的评估中，似乎有必要关注景观尺度。