Comparison of vegetation stages degradation with livestock management using Ellenberg's bioindicators in Chilean Patagonia

Abstract

Different stages of anthropogenic degradation series of one primary shrub were compared in Aisén, Chile. It consisted of a prolonged livestock pasture, with plant ecological indicators recognized and valued by Ellenberg for the factors of light, temperature and reaction, nitrogen and soil moisture. The primary ñirre thicket was considered the beginning of the series. We worked with partial vegetation tables for each state of degradation. Indicator plants as well as nature and utility assessed by multivariate statistical methods for classification and ordination are identified in these tables. Comparison among communities was carried out considering the presence and abundance of selected indicator plants. Results indicate that light and temperature values are concentrated in some parts of the scale from 1 to 9 steps, proposed by Ellenberg; while the others, more dispersed, provide a better differentiation of degradation states. It was possible to characterize the biotopes of all stages of degradation as: sunny, presenting mild temperatures with occasional frost and acid soils, deficient in nutrients and with intermediate moisture. The greatest differentiation was obtained with the latter soil variables that coincided with the position of each of them in the degradation series. This was confirmed by soil tests.