Determining the areas most suitable for urban land use while minimizing impact on natural areas. The case of the Machachi Valley, Ecuador

Due to the impact of urban growth on the environment, especially in developing countries, decision-making tools are needed to help locate the ideal areas for urban use. This study aims to identify the areas most suitable for urban use, minimizing their impact on forest land use in an area with high urban sprawl. As a new development, the study also considers the connectivity between forest-use patches and the loss of forest area as decision variables. The methodology used to determine these areas was AHP (Analytic Hierarchy Process) with GIS (Geography Information System). Twenty experts evaluated the criteria, considering forest conservation in addition to urban suitability. Socio-economic, physical, and environmental criteria and sub-criteria were scored with values from 1 to 5, with 5 indicating the maximum potential of the pixel to accommodate urban use. The study area was the Machachi Valley and the conurbation of Quito in Ecuador. The results indicate that the most suitable urban areas are located in the buffer that surrounds the initial urban use, and the land along the Pan-American Highway. The most vulnerable forest zone was in the south center of Quito and on the hillsides of the Pasochoa volcano. The results were also compared with maps that estimate the evolution of the land uses in this valley in the coming years. Based on this comparison, maintenance of current trends will result in a significant loss of native forest and fragmentation of forest patches in the lower valley. The information provided by maps of suitable urban use is a useful tool to protect the natural resources that land use policies should take into consideration.