Grasslands of the World.pdf - Disasters and Conflicts - UNEP

Grasslands of Patagonia 147
scientists is the use of either empirical or mechanistic simulation models to predict
year-to-year fluctuations in forage availability and adjust animal numbers
accordingly. The empirical approach involves the use of seasonal rainfall data
to make stocking rate adjustment decisions following within-year patterns of
drought or moisture surpluses (Rimoldi and Buono, 2001). The mechanistic
approach includes the parameterization of existing mechanistic spatiallyexplicit
models that allow landscape -scale simulation of primary productivity
and grazing at a number of different time scales of interest. This approach
involves the use of satellite image analysis to calibrate productivity estimates
(Ellis and Coughenour, 1996).
In recent years there has been increasing demand for long-term range
monitoring tools at scales ranging from individual pastures to landscapes and
ecosystems . Current range assessment routines cannot (in most cases) provide
useful long-term monitoring information. Furthermore, land uses other than
grazing , such as oil extraction or other mining, require the development of
tools tailored to the type of environmental disturbance they produce. Landsat
TM satellite image analysis has been used over the last decade to make an
inventory of the state of Patagonian rangelands (degrees of desertification)
in several key areas of the region (del Valle et al., 1995). As the availability of
satellite images increases, much of the installed capabilities in research institutes
throughout the region will be used as a basis for multi-temporal monitoring
of rangelands at regional scales. At smaller spatial scales, Ares et al. (2001a,b)
are developing methods of monitoring changes in vegetation structure under
grazing at landscape scales in the Monte shrub steppes using aerial photographs
and spatially-explicit simulation modelling .
RESTORATION ACTIVITIES
Restoration activities have traditionally been restricted to the stabilization of
sand accumulations in severely eroded areas, using special cultivation techniques
and generally involving the seeding of rhizomatous grasses of the genus Elymus
(Castro, Salomone and Reichart, 1983). Almost all of these activities have been
conducted successfully, by both INTA and the Board of Agriculture (Consejo
Argario Provincial) of the Province of Santa Cruz. Although this and other
variants of grazing -related restoration activities continue (Magaldi et al., 2001;
Becker, Bustos and Marcolín, 2001; Rostagno, 2001), current efforts in this field
have mostly shifted toward the reclamation of disturbances associated with the
mining and oil industries (Baetti et al., 2001; Ciano et al., 2001).
Currently, restoration activities involve: the developing or adaptation of
technologies to promote in situ biodegradation of oil (especially in situations
where oil spills affect valuable riparian meadow habitats) (Luque et al., 2000;
Nakamatsu et al., 2001b); conducting conservationist tillage in areas of topsoil
decapitation (Ciano et al., 2000); and selection of native ruderal species for
revegetation of highly degraded environments (Ciano et al., 1998). Shrubs of