Evaluación ambiental integrada de áreas inscritas en el programa federal de Pago por Servicios Ambientales Hidrológicos. Caso de estudio: Ajusco, México

Since the specific problem of deforestation on an international level, they have created compensation mechanisms for ecosystem services, which have recently been increasing interest in the academic and government sectors, however, a lack of information on their potential effects is detected, especially from the aspects of integrative approach and spatial. Therefore, this work presents the case study of the community of San Miguel and Santo Tomas Ajusco, located on the suburbs of México City, because the community has participated in the federal program payments for hydrological environmental services (phes) since 2004. Based on the construction of longitudinal profiles (which are incorporated thematic geographic information layers) we analyzed if there is correspondence between the potential of ecosystem services and enrolled in the program areas. In addition, the effectiveness of the program regarding deforestation detected in the area was observed. For the profiling, it is noticed the exercise of combining the different layers selected for analysis, forming a two-dimensional model that allows us to appreciate the altitudinal gradient of the area with its biophysical components (vegetation and land use, soil science, geology and landforms highlights) with information environmental Services (ES). This facilitates the analysis of all these variables and has the advantage that it can be adapted to the number of variables we have, since they must only be incorporated to the profile (with pretreatment data).

The profiles helped to identify whether registered in the phes program areas correspond to the most important areas for the provision of environmental services; however, a complementary work was developed consisting of a map which would bring together the most important areas for the contribution of es; This was generated by applying the statistical model of Jenks’ Natural Breaks “(which allows to discriminate classes by the similarity of values that compose them), in the layers of ES that it had (potential infiltration, carbon stock in forests, surface runoff and provision of habitat), establishing quantitative 5 for each category. The criterion model allow standardize classes; therefore, quantitative categories were matched to (very low, low, medium, high and very high) qualitative categories. Then the “high” and “very high” categories were selected and merged into a map with software tools Arc. map 10.1. denominating as “high priority areas for ecosystem services”.

ES mapping was deployed with phes polygons and correspondence between sites on phes and areas with greatest potential for ES (except for an area of 236.7 hectares) was found. However, in many cases, the highest values of es not correspond to water resources, as they are more associated with vegetation and biodiversity (carbon stock in forestsand provision of habitat), which helps to conclude that the phes program should consider other variables and not be restricted to the es associated with hydrology. Two studies on quantifying forest cover were reviewed in the area (one covers from 1986 to 2010, with a projection to 2030 and the other from 2006 to 2014). The information regarding sites on phes Program and the result shows that deforestation has remained revised (although the rate decreased in the period 2006-2014) and deforested areas within enrolled in the program areas phes are greater than those who have not been. Although factors that could contribute to the process are identified, it is concluded that a program like phes implemented in an isolated manner, has no bearing on the problem of deforestation. Finally, the importance of obtaining the map “high priority areas for ecosystem services”, the most environmentally important areas are identified and this helps manage phes expanding areas and get other resources or protection status in areas with natural ecosystems.