Multi-scale indicators of land degradation in the Patagonian Monte, Argentina. Environmental Management

BERTILLER, M.B; ARES, J.O.; BISIGATO, A.J.

ENVIRONMENTAL MANAGEMENT

SPRINGER

Año: 2002 vol. 30 p. 704 - 715

0364-152X

/ Depletion of vegetation by overgrazing in arid environments has long-lasting effects on the environmental qualityover extended geographic areas. An adequate inspection of habitat changes requires scaled up procedures that would allow assessing end-points of environmental status in broad areas thatwould be based on processes occurring at the plant canopylevel. Our purpose was to find indicators of land degradation?conservation status for use in land monitoring programs and inplanning management practices that would be amenable to further up-scaling for use with remotely sensed imagery. In severalsites of the Patagonian Monte differing in the impact of grazingmanagement, we evaluated vegetation attributes at three spatialscales. At the population scale, we found that the severity ofgrazing impact was characterized by the reduction of the palatable grass, P. ligularis, outside and inside shrub canopies. At thevegetation patch scale, we found that land degradation by domestic herbivore impact was characterized by changes in attributes of patch shape (radius, height, internal canopy cover)and patch abundance. At the plant community scale, we foundthat the structure of the plant canopy as described using Fourieranalysis of cover data changed after long-term grazing impactconsistently with the modifications in plant population and patchstructures. We present a conceptual multiscale scenario of structural changes triggered by domestic herbivore impact, and quantitative indicators of plant structure and processes useful to develop management strategies of the Patagonian-Monte thatwould conserve its natural habitats. The developed end-pointsare also amenable for use in land conservation assessmentthrough remotely sensed imagery.