Programs making payments for ecosystem services (PES) are an increasingly popular policy tool worldwide for conserving forest cover and ecosystem functioning. Likewise, an increasing number of PES evaluations highlight issues that need to be addressed to improve effectiveness including better spatial targeting and modeling or monitoring of ecosystem service provisioning. Such efforts are needed not only to evaluate past PES performance but also to anticipate future challenges. While a number of studies have explored how deforestation and other land-use/cover (LULC) changes may affect the provisioning of important ecosystem services, relatively few have addressed the potential impacts of climate change (CC), and even fewer have explored how these processes may interact. We analyzed potential changes in key ecosystem services due to the individual and combined effects of LULC and CC in watersheds in central Veracruz, Mexico. Both LULC and CC scenarios were developed under assumptions of business as usual and worsening conditions derived from the SRES B2 and A2 emission storylines, and the RCP 4.5 and 8.5 scenarios of the IPCC-Emission Scenario Narratives for 2039, respectively. Eight different scenarios were developed and evaluated (2 for LULC, 2 for CC, and 4 combined) using LCM from TerrSet for LULC changes and InVEST to model expected changes in annual water yield, soil retention, and carbon storage.
Results/Conclusions
Predicted land-use changes included agricultural and grassland expansion versus shade coffee, cloud forest, and temperate forest. These changes were expected to provoke low to moderate decreases in water yield (18.4 to 20.16%) and marginal declines or moderate increases in soil retention (-6 to 13.4%). Only LULC change significantly reduced carbon storage (3.8 to 7.3%) but results should differ for carbon sequestration. CC was found to decrease soil retention due to the erosive effect of increased rainfall. Relative to baseline conditions (2003-2014), combined scenarios predicted pronounced declines in annual water yield (12.5 to 18.3%) and increasing soil erosion (54 to 71.3%), due mainly to marked increases in evapotranspiration and rainfall. These changes were similar but more pronounced compared to those seen under the individual effects of CC, suggesting a predominant role of climatic change in driving responses in ES provisioning. These changes are analyzed in the context of current areas receiving PES in central Veracruz. PES Program operators are encouraged to incorporate such findings to help improve spatial targeting and program effectiveness in the future.