Silvopastoral systems in Patagonia, Argentina

PERI, PL; CABALLÉ, G; HANSEN, NE; BAHAMONDE, HA; LENCINAS, MV; VON MÜLLER, AR; ORMAECHEA, S; GARGAGLIONE, V; SOLER, R; SARASOLA, M; RUSCH, V; BORRELLI, L; FERNÁNDEZ, ME; GYENGE, J; TEJERA, LE; LLOYD, CE; MARTÍNEZ PASTUR, G

Temperate agroforestry systems

CABI

Año: 2018; p. 252 - 273

Patagonia region includes five provinces (Neuquén, Río Negro, Chubut, Santa Cruz and Tierra del Fuego) with an area of 197 million hectares and extends from latitudes 37 to 52º 30 S (Fig. 11.1). There are four main ecosystems within the region: the steppe (representing ~93% of total area), where extensive sheep production is the main activity; the Andes Mountains, where most of the native forests grow on a narrow 100 km wide strip of land (~1.8%); the ecotone defined as forest?steppe boundary (~3.7%); and the valleys (~1.5%) where agricultural production is animportant alternative (Peri, 2009a). In addition to native vegetation, exotic trees were planted to satisfy the demand for timber products in the region. Rainfall decreases from 4000 to 200 mm yr?1 from west to east across the Andes Mountains, which act as an orographic barrier to moist winds coming from the west. This distinct precipitation gradient, together with local edaphic and topographic variations, substantially influences patterns of vegetation distribution. In the late 1800s, agricultural activities in the ?Pampas? region near Buenos Aires expanded rapidly, and as a result, livestock production (mainly sheep) was pushed into marginal areas such as Patagonia (Table 11.1). The unknown carrying capacity of Patagonian rangelands resulted in severe overstocking,and this, coupled with the fragility of the environment, the mismanagement of natural resourcesand other socioeconomic aspects led to a major degradation of the natural resource base. There are more than 6.5 million hectares affected by desertification (del Valle etal., 1995), where annual pasture production does not exceed 40 kg DM ha?1. Furthermore, national and provincial governments began to promote the planting of fast-growing exotic forest species in Patagonia to solve the problem of timber demand and at the same time to diversify the regional production systems using grassland or shrub land sites with different levels of degradation.