Variación de la composición específica y cobertura del pastizal bajo diferentes presiones de pastoreo en el Monte rionegrino

GUADALUPE PETER; FLAVIA A. FUNK; ALEJANDRO LOYDI; ANA I. CASALINI; CINTIA V. LEDER

PHYTON - INTERNATIONAL JOURNAL OF EXPERIMENTAL BOTANY BA ARGENTINA

FUNDACION ROMULO RAGGIO

Año: 2012 vol. 81 p. 233 - 237

0031-9457

In the western Monte Phytogeographical Province of Rio Negro, vegetation is a shrubby-grassland steppe, where plants are interspersed within a bare soil matrix forming ?phytogenic islands?. The objective of this study was to evaluate the specific composition and cover of the study ecological system under different grazing pressures. We selected areas with high, moderate and low grazing intensity at three sites. In each area we established five linear transects, where basal cover and all intercepted species were registered. Sites were arranged through a Principal Component Analysis using the Infostat software. We analyzed similarity between sites, considering basal cover and species present in islands and inter-islands, and in both situations together. Islands and inter-islands were separated especially by the presence of shrubby species. Exclosure areas showed a greater cover of Poa ligularis, litter and biological crusts, whereas intense grazed areas presented a greater cover of bare soil. Grazing by itself and different grazing pressures can modify the specific composition at an island and inter-island scale. Greater cover of biological crusts could help recovery of the study system.