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The effectiveness of Payments for Ecosystem Services (PES) in Mexico may be reduced by a lack of guidance on intra-watershed priority zones and an overemphasis on water supply versus other services such as water quality. We explored the links between land use, water quality, and public health in central Veracruz. We identified zones of high and low cholera prevalence and evaluated the effects of land use on water quality at different scales. Production functions were used to evaluate relationships between water quality and public health. Additionally, using mitigation and defensive costs methods and a combined regression model, we estimated a marginal value per hectare of forest in avoiding public health costs associated with contaminated water. Prevalence of cholera was associated with E. coli concentrations in streams. Primary forest cover was the land use most strongly correlated with E. coli, particularly within riparian corridors of 100 m width. Our results suggest a value of water quality regulation of at least $US 90 ha−1 in riparian corridors. These results highlight the importance of targeting PES in priority areas within watersheds and considering both water quality and quantity as a means of increasing program efficiency and potencially broadening financial support for these programs.

La Reserva de la Biosfera Los Tuxtlas (RBLT) alberga los ultimos remanentes de bosque tropical perennifolio (BTP) y bosque mesofilo de montana (BMM) en la llanura costera del golfo de Mexico. Sin embargo, en las ultimas decadas ha perdido ~ 60% de su cobertura forestal. La informacion precisa y detallada sobre la dinamica del cambio de uso del suelo es fundamental para implementar planes de manejo/conservacion pertinentes a la situacion actual y futura de una region. El objetivo del trabajo fue determinar la dinamica reciente de los cambios espacio-temporales del uso del suelo y la cobertura vegetal, con un alto grado de precision en la RBLT. Se evaluaron 3 imagenes satelitales (2006, 2011 y 2016) mediante fotointerpretacion manual a escala fija de 1:5,000. Entre 2006 y 2016, la tasa de deforestacion fue de 0.8% anual, siendo la vegetacion arborea de franjas riberenas la categoria mas deforestada (~ 1,300 ha). Se registro una transicion de ~ 550 ha de pastizales a cultivos, sugiriendo un cambio de actividad economica en zonas de la reserva. Dada la importancia ecologica de las franjas riberenas como elemento conector del paisaje, es urgente protegerlas particularmente en la zona de amortiguamiento. Las zonas nucleo han protegido el BTP y el BMM eficientemente.

Payment for hydrological services (PHS) are popular tools for conserving ecosystems and their water-related services. However, improving the spatial targeting and impacts of PHS, as well as their ability to foster synergies with other ecosystem services (ES), remain challenging. We aimed at using spatial analyses to evaluate the targeting performance of México's National PHS program in central Veracruz. We quantified the effectiveness of areas targeted for PHS in actually covering areas of high HS provision and social priority during 2003-2013. First, we quantified provisioning and spatial distributions of two target (water yield and soil retention), and one non-target ES (carbon storage) using InVEST. Subsequently, pairwise relationships among ES were quantified by using spatial correlation and overlap analyses. Finally, we evaluated targeting by: (i) prioritizing areas of individual and overlapping ES; (ii) quantifying spatial co-occurrences of these priority areas with those targeted by PHS; (iii) evaluating the extent to which PHS directly contribute to HS delivery; and (iv), testing if PHS targeted areas disproportionately covered areas with high ecological and social priority. We found that modelled priority areas exhibited non-random distributions and distinct spatial patterns. Our results show significant pairwise correlations between all ES suggesting synergistic relationships. However, our analysis showed a significantly lower overlap than expected and thus significant mismatches between PHS targeted areas and all types of priority areas. These findings suggest that the targeting of areas with high HS provisioning and social priority by Mexico's PHS program could be improved significantly. This study underscores: (1) the importance of using maps of HS provisioning as main targeting criteria in PHS design to channel payments towards areas that require future conservation, and (2) the need for future research that helps balance ecological and socioeconomic targeting criteria.

Background Many authors have claimed that snakebite risk is associated with human population density, human activities, and snake behavior. Here we analyzed whether environmental suitability of vipers can be used as an indicator of snakebite risk. We tested several hypotheses to explain snakebite incidence, through the construction of models incorporating both environmental suitability and socioeconomic variables in Veracruz, Mexico. Methodology/Principal Findings Ecological niche modeling (ENM) was used to estimate potential geographic and ecological distributions of nine viper species' in Veracruz. We calculated the distance to the species' niche centroid (DNC); this distance may be associated with a prediction of abundance. We found significant inverse relationships between snakebites and DNCs of common vipers (Crotalus simus and Bothrops asper), explaining respectively 15% and almost 35% of variation in snakebite incidence. Additionally, DNCs for these two vipers, in combination with marginalization of human populations, accounted for 76% of variation in incidence. Conclusions/Significance Our results suggest that niche modeling and niche-centroid distance approaches can be used to mapping distributions of environmental suitability for venomous snakes; combining this ecological information with socioeconomic factors may help with inferring potential risk areas for snakebites, since hospital data are often biased (especially when incidences are low).