Los bosques de quebrada de la costa maulina: evaluación espacial y vegetacional en un contexto de cambio climático y de impactos antrópicos

Abstract

In the coastal mountain range of the Maule region, 23 ravine rain forests dominated by canelo (Drimys winteri) and various native myrtaceae species were described in phytosociological terms in a study published in 1988. Thirty years later, 20 of those forests were located again in order to document their current situation in a context of successive anthropic impacts and climate change. Changes in land cover were evaluated through the comparative analysis of Landsat images from 1987, 2003 and 2017; the changes in plant composition, characterizing the vascular flora by means of the modified Braun-Blanquet phytosociological method and; the natural regeneration of woody species in plots of 1 m² inside and outside the ravine forests. Between 1987 and 2017, the area occupied by native forest in the circular areas included in the study was reduced by 72 %. The importance and presence of significant species reported in the original inventories decreased in the hygrophilous forests and sclerophyllous and invasive species entered. The regeneration of native trees and native creeping and climbing species was higher inside the ravine forests, while the germination of native shrubs was higher at the edge of these. The modification of the surrounding matrix of forests due to the increase in anthropic pressure and an advance in stressful conditions as a consequence of climate change explain the observed changes.