Detección de cambios en la cobertura vegetal y usos del suelo en microcuenca Las Piedras, Municipios de Tangua, Nariño, Colombia, entre los años 2002- 2012

Abstract

There is a substantial variability in the vegetation cover in the Las Piedras micro-watershed, Las Piedras, Municipality of Tangua, generated mainly by the intervention of the inhabitants, expressed in deforestation, inadequate management of natural resources and expansion of the agricultural frontier; in addition, the municipality of Pasto, contemplated as a priority and short-term objective the supply of water for the city, from this area; So far, in the Las Piedras micro-watershed, planning processes arenot significant, and the competent authorities do not ensure the establishment of management and control systems in the future regarding the use and local management of the vegetation cover, which will lead to the vulnerability and accelerated deterioration of these resources. For the conservation and maintenance of natural resources, it is necessary to study and analyze the entire hydrographic unit in the system in which it develops, with adequate knowledge of its resources and the system of relationships between natural and anthropic elements. In pursuit of this purpose, a supervised multitemporal analysis was applied, based on the recognition of spectral signatures of LANDSAT TM and ASTER satellite images, from the years 2002 and 2012, determining the classification and field supervision of the vegetation covers found in the micro-watershed in the studied period; so far, the partial study for the first period is presented.As a result of this process, an approximation of the current state of conservationin the Las Piedras micro-watershed was made; 28.95% corresponding to 501.27 ha of the total of 1,731.52 ha were identified, which presented changes in the vegetation cover during the first 13 years analyzed. Many of these changes were caused by the extraction of wood for the production of firewood and charcoal and by agricultural and livestock practices that are not the most appropriate for adequate management in the study area.