Geomorphology and pastoral-agricultural land use in Cotahuasi and Puica, southern Peruvian Andes

Abstract

In Cotahuasi and Puica, southern Peru, contrasting landforms of wide plateaus with glacigenic U-shaped valleys (4,800-5,000 m ASL) and deep canyons (1,500-2,800 m deep from plateaus) are developed. In this area, camelid (alpaca and Ilama) pastoralism and agriculture have been conducted on the plateaus and in the canyons, respectively, since at least Inca times. This paper describes meso- to micro-scale landforms comprising the plateaus and canyons, and discusses the factors controlling pastoral-agricultural land use of these specific landforms. On the plateaus, flood plains, fluvial terraces, alluvial fans, taluses, and landslide bodies, which are concentrated in the U-shaped valleys, are significant for alpaca pastoralism. These landforms provide relatively gentle slopes, and are covered by wet meadows for livestock if adequate water is supplied by channels or springs. In the canyons, landslide bodies, taluses, alluvial fans, and fluvial terraces are important for agriculture. These landforms also produce gentle places, and are used even if irrigation or channels are absent. The regional/ local climate would be the primary factor for the vertical separation between pastoralism and agriculture. Additionally, the physiographical setting, in particular the slope angle, is potentially important for the pastoral-agricultural land use of meso-to micro-scale landforms.