Multiscale Indicators of Land Degradation in the Patagonian Monte,Argentina |
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Authors: | MÓNICA B BERTILLER JORGE O ARES ALEJANDRO J BISIGATO |
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Institution: | (1) Centro Nacional Patagónico-CONICET, Boulevard Brown s/n 9120 Puerto Madryn, Chubut, Argentina, AR |
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Abstract: | Depletion of vegetation by overgrazing in arid environments has long-lasting effects on the environmental quality over 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 that would be based on processes occurring at the plant canopy level. Our purpose was
to find indicators of land degradation–conservation status for use in land monitoring programs and in planning management
practices that would be amenable to further up-scaling for use with remotely sensed imagery. In several sites of the Patagonian
Monte differing in the impact of grazing management, we evaluated vegetation attributes at three spatial scales. At the population
scale, we found that the severity of grazing impact was characterized by the reduction of the palatable grass, P. ligularis, outside and inside shrub canopies. At the vegetation 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 found that the structure of the plant canopy as described using Fourier analysis of cover data
changed after long-term grazing impact consistently with the modifications in plant population and patch structures. 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 that would conserve its natural
habitats. The developed end-points are also amenable for use in land conservation assessment through remotely sensed imagery. |
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Keywords: | : Arid lands Herbivore impact Habitat fragmentation Fourier spectral analysis |
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