The close link between temperate forest ecosystems and human populations in Mexico, positions those forests among the main terrestrial ecosystems, most vulnerable to overexploitation, fragmentation and land use change.
Fragmentation, as a phenomenon that divides the landscape into a number of units called patches, whose size, shape, connection and degree of isolation is different from the original area, has been extensively studied to evaluate its implications on biological diversity, particularly in distribution of species, reproductive mechanisms, succession and habitat regeneration, to name a few. However, the study of fragmentation as a process that can alter the dynamics and functionality of forests would allow us to understand the implications on the capacity to provide ecosystem services like hydrological services. Particularly the process of fragmentation and land use change are phenomena that can alter hydrological processes such as the interception of rainwater in situations where there is an extensive change in the use of forest land by open areas, when the physical characteristics of the soils change to become more compact and less permeable. Moreover, forest fragmentation has the capacity to increase the surface runoff of the system, producing high levels of sediment in water flows and, therefore, poor water quality. As a consequence of the alteration in the hydrological processes, the quality and quantity of water that is obtained from the forests can be affected. The forests of the Izta-Popo region in central Mexico belongs to the temperate forests of the Valley of Mexico, thus their importance lies in being one of the main water provider for Mexico City.
This study evaluates the implications of the fragmentation of forests in the Izta-Popo region on hydrological processes. In order to know the spatial configuration of forest fragmentation, LANDSAT images (30x30 resolution) were classified for the years 1970 and 2016 by Geographic Information Systems ArcGIS 10.3 and FRAGSTAT tools.
Results/Conclusions
The results show that forests in 2016 have more patches, smaller size and a greater degree of isolation than the 1970s. On the other hand, to evaluate the hydrological components of the system, climatological, vegetation and physical and chemical characteristics of soil that have been collected over a period of fifteen years and will be evaluated through the SWAT (Soil and Water Assessment Tool) program, I expected to explain that the changes in the land use of the study area are relationated with the increase in runoff and the low retention potential.