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

Grasslands of Patagonia 149
in the province of Neuquen, created in 1940), and Bosques Petrificados Natural
Monument (100 km 2 in the province of Santa Cruz) (Villamil, 1997).
Seed production
Although experimental sowing of native species has been successful in southern
Patagonia , forage productivity of native plant species under cultivation was
lower than that of introduced grasses and legumes (Mascó, 1995). Reseeding
trials on degraded land were conducted in the sixties by an INTA-FAO
Project (Molina Sanchez, 1968). Reseeding was biologically successful at many
sites, but productivity under low moisture regimes was considered limiting
for commercial application (Mascó and Montes, 1995), mostly because sheep
production was the only activity considered in the economic analyses.
These results constrained local seed production to limited areas, namely:
harvesting small stands of Elymus sabulosus and E. arenarius in western Santa
Cruz and south-central Chubut to obtain seed for sand dune fixation; setting
up two active gene banks in the region, which not only stored seed collections
from natural stands, but also multiplied some material in experimental plots
(Montes et al., 1996); and developing oil spill reclamation technology by scientists
at INTA’s Research Station in Trelew (Chubut), which included the setting
up of a nursery to multiply native shrub germplasm such as Atriplex lampa to
provide plantations at disturbed sites. There is currently no public or private
funding for seed production of native species nor for rehabilitation of desertified
areas with native plant species.
RECOMMENDATIONS AND LESSONS LEARNED
Most of the grazing management and ecology research in Patagonia has been
conducted by INTA and institutions such as CONICET and the University of
Buenos Aires. Beginning in the 1980s, pasture condition guides were proposed
for evaluating different vegetation types . Initially, grazing treatments were recommended
based on range management literature. The lack of understanding
of soil-plant-animal relations thwarted further progress. Soil and vegetation
responses to different grazing treatments were unknown. The nutritional and
behavioural aspects of the grazing process were ignored. Realizing this, two longterm
grazing trials were designed and conducted by INTA, one in SW Chubut
(Siffredi et al., 1995) and one in southern Santa Cruz (Oliva et al., 1998).
Many rangeland evaluation techniques and recommended grazing strategies
were thereafter based on the findings of INTA grazing trials. Short-grass biomass
and key species height were used to assess carrying capacity and grazing
intensity, respectively, in grass-dominated rangelands of Southern Patagonia
(Borrelli and Oliva, 1999; Cibils, 1993). Pastoral Value (Daget and Poisonnet,
1971), a method based on step-point cover data, was proposed for shrubland
steppes in northern Patagonia (Elizalde, Escobar and Nakamatsu, 1991; Ayesa
and Becker, 1991)