Abstract

CAMARGO-GARCIA, Juan Carlos et al. Soil changes after a fire event in a páramo ecosystem: Los Nevados Natural National Park, Colombia. Acta Agron. [online]. 2012, vol.61, n.2, pp.151-165. ISSN 0120-2812.

A fire event occurred in 2006, affected about 2400 ha of Páramo ecosystems located on the surroundings areas of Otún lagoon (4 ° 46' 58.4" N y 75° 24' 26.8" W) in the Nevados Natural National Park, Colombia. Because of the worth of this area associated with the supplies of ecosystems services and the need for finding variables as indicators of soil conditions, in areas affected and non-affected by fire physical and chemical properties of soils were evaluated. The soil assessment was conducted out in areas where restoration strategies had been implemented and on two geomorphologic positions (Valleys and hills). Samples for monitoring soils were done at once of the fire, two years (2008) and three years (2009) later. To identify differences in soil characteristics evaluated between sites affected and non-affected, topographic positions and restoration treatments, a nonparametric test Kruskal-Wallis was applied. Subsequently, using the correlation coefficient of Spearman the relationships between variables were analyzed. Soils of valley positions were drastically affected and more than 50% organic matter was lost. Consequently, physical properties of soils such as bulk density and structural stability were also deteriorated. Three years after the implementation of restoration activities, there are not evidences of the improvement of soils conditions; in fact, some properties tend to be more deteriorated. Results obtained in this study permit to elucidate some variables which could be used as indicators for monitoring programs with emphasis on this resource. Also, the fragility of Páramo ecosystems is showed by means of soils deterioration. The restoration of soils properties affected by fire is indeed a very slow process even beyond of the time used in this study. In fact, to determine the effect of restoration strategies and to define those more adequate might take a long time. Therefore, it is imperative to avoid any activity or event capable of generating deterioration of this strategic ecosystem.

Keywords : Colombia; forest fires; Los Nevados Natural Park; páramo ecosystem; physicochemical properties of soil.

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