Tal Svoray
Maxim Shoshany
Human intervention in Mediterranean and semi-arid ecosystems results in complex vegetation patterns and threat for soil degradation and deterioration of primary production. Range management of large areas under such conditions requires adequate and updated information regarding the status and dynamics of vegetation patterns. This paper investigates the usefulness of Landsat TM and JERS-1 satellite images for determining effects of goat grazing and clearing treatments on the recovery processes of Mediterranean shrubland. Eight slope units representing different histories of grazing pressures and clearing treatments were selected for this purpose. Spatial variations of vegetation cover, as determined by NDVI (Normalised Difference Vegetation Index) distributions in the slope units, were analyzed on the basis of summer images from 1992 and 1997. The use of temporal data allowed the assessment of natural vegetation regrowth rates. The results show that image statistics correspond well with: grazing intensities; length of the regrowth process; and grazing habits of goat herds. Proximity analysis conducted using GIS (Geographic Information Systems) techniques revealed that grazing intensity pattern follows the shortest path connecting the water source and the corral rather than spreading in wide areas across the slopes. It is suggested that remote sensing and GIS analysis can be used for monitoring slopescale impacts of grazing and treatments on woody vegetation such as Mediterranean scrubland and woodland.
Tal Svoray
Maxim Shoshany
Human intervention in Mediterranean and semi-arid ecosystems results in complex vegetation patterns and threat for soil degradation and deterioration of primary production. Range management of large areas under such conditions requires adequate and updated information regarding the status and dynamics of vegetation patterns. This paper investigates the usefulness of Landsat TM and JERS-1 satellite images for determining effects of goat grazing and clearing treatments on the recovery processes of Mediterranean shrubland. Eight slope units representing different histories of grazing pressures and clearing treatments were selected for this purpose. Spatial variations of vegetation cover, as determined by NDVI (Normalised Difference Vegetation Index) distributions in the slope units, were analyzed on the basis of summer images from 1992 and 1997. The use of temporal data allowed the assessment of natural vegetation regrowth rates. The results show that image statistics correspond well with: grazing intensities; length of the regrowth process; and grazing habits of goat herds. Proximity analysis conducted using GIS (Geographic Information Systems) techniques revealed that grazing intensity pattern follows the shortest path connecting the water source and the corral rather than spreading in wide areas across the slopes. It is suggested that remote sensing and GIS analysis can be used for monitoring slopescale impacts of grazing and treatments on woody vegetation such as Mediterranean scrubland and woodland.