Evaluating the environmental effectiveness of payments for hydrological services in Veracruz, México: A landscape approach

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.