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

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Grasslands of the world
the genera Atriplex , Grindelia and Tamarix are being used in many current
restoration projects, with establishment rates of almost 70 percent (Ciano et
al., 2001).
Most land reclamation activities are currently in a region with some of the
oldest oil fields of southern Patagonia (northern Santa Cruz and southern
Chubut), and lie mostly within the shrub-grass steppes and semi -desert biozones
. Recently, there has been a rapid growth in the demand for further land
reclamation technology by a number of large mining projects in the southern
semi-desert biozone (Province of Santa Cruz), a need that is currently being
met by local Universities. Mine reclamation will possibly be one of the fastest
growing applications of restoration in certain areas of Patagonia during the
decades to come.
BIODIVERSITY MAINTENANCE
There are 1 378 recorded vascular plant species in arid and semi -arid Patagonia
(Correa, 1971), almost all of which are angiosperms and close to 30 percent of
which are endemic species. Of all species recorded in the Flora of Patagonia,
there are about 340 exotic plants that are restricted to areas surrounding
houses, pens and roads, but they are, in all cases, unable to become part of the
native steppe plant communities (Soriano, Nogués Loza and Burkart, 1995).
Due to its relatively high level of endemism, Patagonia has been recently
included as a “Centre of Plant Diversity ” (CPD Site A46) in a worldwide
diversity conservation project under the auspices of the Museum of Natural
History of the Smithsonian Institution (USA ), IUCN and WWF (Smithsonian
Institution, 1997).
Sheep grazing has been shown to reduce vascular plant diversity in several
Patagonian ecosystems , both by promoting local extinction of preferred forage
plants and by altering the relative abundance of species in the grazed plant
communities (Schlichter et al., 1978; Perelman, León and Bussacca, 1997; Oliva
et al., 1998; Cibils et al., 2000; Cesa and Paruelo, 2001). Soriano, Nogués Loza
and Burkart (1995) assembled a list of 76 endangered species in Patagonia ,
of which a quarter are grasses, on the basis of the plant species replacement
patterns under grazing described by several authors in Paruelo et al. (1993).
Although the severity of extinction risk is not equal for all species listed by
Soriano, Nogués Loza and Burkart (1995), this list would clearly be a good
starting point to guide conservation efforts. Current efforts to prevent overgrazing
may contribute to slowing down the rate of loss of endemic species,
although these programmes do not address the biodiversity issue explicitly.
Unfortunately there are few nature reserves in arid and semi -arid Patagonia,
although many of the National Parks along the Patagonian Andes include
areas of steppe-forest ecotone (Villamil, 1997). There are currently only two
reserves well within arid and semi-arid Patagonia, which account for less than
0.1 percent of the region, namely Laguna Blanca National Park (about 110 km 2