INVESTIGADORES
BERTILLER Monica Beatriz
congresos y reuniones científicas
Título:
Multiple-scale plant indicators of grazing disturbance in patchy arid ecosystems of the Patagonian Monte, Argentina.
Autor/es:
BERTILLER, M. B.; ARES, J.O.; BISIGATO, A.J.
Lugar:
Freising-Weihenstephan
Reunión:
Simposio; 44th IAVS Symposium.; 2001
Institución organizadora:
International Association for Vegetation Science
Resumen:
The effect of grazing on the spatial structure of vegetation was investigated in the Patagonian-Monte at different stocking rates, grazing pressures, and recovery times after grazing. We predicted increased heterogeneity in the spatial distribution of plant patches, reductions in patch size, increased patch number, and decreased abundance of palatable grasses with increasing grazing. To assess changes, (i) we used standard Fourier?s spectral analysis (community scale), (ii) we compared the shape of plant patches (patch scale), (iii) we estimated the density of the palatable grass Poa ligularis growing inside or outside woody patch crowns (population scale). We found that the spatial organization at the community scale was affected by grazing in accordance with our predictions, increasing stocking rates and/or grazing pressures resulted in increased patch number and decreased patch size, and outsider P. ligularis plants were first and more intensively depleted than insider plants. Structural changes at the community scale were strongly related to those at the patch scale (r=0.99, P