Pampas

Pampas (Span. La Pampa, from a Quichua word signifying a level open space or terrace), an extensive plain of Argentina, extending from the Rio Colorado north to the Gran Chaco, and from the foothills of the Andes east to the Parana and Atlantic coast.' It consists of a great calcareo-argillaceous sheet, once 1 There are other pampas in South America, such as the Pampas de Aullagas, in Bolivia, the Pampas del Sacramento between the Huallaga and Ucayali rivers in eastern Peru, and others less well known, but when the word Pampas is used alone the great Argentine plain is meant.

the bed of an ancient sea, covered on the west by shingle and sand, and on the east by deposits of estuaiy silt of irregular thickness brought down from the northern highlands. Its western and northern limits, formed by the foothills and talus slopes of the Andes, and by the south of the great forested depression of the Gran Chaco, cannot be accurately defined, but its area is estimated at 200,000 to 300,000 sq. m. Its greatest breadth is across the south, between the 36th and 37th parallels, and its least in the north, where the eastern ranges of the Andes project deeply into its north-western angle. Its surface is broken in the north-west by the sierras of Tucuman, Catamarca, San Luis and Cordoba, the latter rising from the midst of the plain, and by some small isolated sierras and hills on the south. It has a gradual slope from north-west to south-east, from an elevation above sea-level of 2320 ft. at Mendoza to 20 ft. at Buenos Aires on the La Plata - the distance across (between Mendoza and Buenos Aires) being about 635 m. There are other slight irregularities in its surface, such as the longitudinal depression on the west, the saline, arid depression west of the Cordoba sierras, the Mar de Chiquita depression N.E. of Cordoba, and some smaller areas elsewhere. Apart from these the plain appears perfectly level. The east, which is humid, fertile and grassy, has no natural arboreal growth, except in the vicinity of Cordoba and in the north, where algarrobas and some of the Chaco species are to be found. In the extreme south some species of low, thorny bushes cover considerable areas in the vicinity of the hill-ranges, otherwise the plain is destitute of native trees. Since the arrival of Europeans several species have been introduced successfully, such as the eucalyptus, poplar, paraiso (Melia Azedarach), peach, willow, ombu (Pircunia) and others.

The distinctive vegetation of the grassy pampas is the tall, coarse-leaved "pampas grass" (Gynerium argenteum) whose feathery spikes often reach a height of eight or nine feet. It covers large areas to the exclusion of all other species except the trefoils and herbs that grow between its tussocks. The natural grasses of the pampas are popularly divided into pasta dura  (hard pasturage), which includes the large, tussock-forming species, and pasta molle (soft pasturage), the tender undergrowth. Since the advent of Europeans other forage plants have been introduced, the most successful and profitable being alfalfa or lucerne (Medicago sativa), which is widely cultivated both for hay and for green pasturage for the fattening of market stock.

West of this region is a dry, sandy, semi-barren plain, called the "sterile pampas." It has large saline areas, brackish streams and lakes, and immense sandy deserts, and in singular contrast to the fertile, treeless region of the east it supports large areas of stunted trees and thorny bushes. Most prominent in this hardy but u?lattractive growth is the "chanar" (Gurliaca  or Gourliaca decorticans), which is characteristic of the whole area, and led Professor Griesbach to suggest the substitution of "formacion del chanar" for "formacion del monte," the designation adopted by botanists for this particular region. The chanar is thorny and of low, irregular growth, and furnishes a strong durable wood and a sweet fruit.

The grassy plains are well watered by streams flowing to the Para* La Plata and coast, though some of these are brackish. There are large saline areas in northern Santa Fe, Santiago del Estero and Cordoba provinces, and throughout the greater part of the pampean plain wells cannot be sunk lower than 18 or 20 ft. without encountering brackish water. On the sterile pampas these conditions are still more common, the drainage southward through the Desaguadero and Salado being charged with saline matter. There are many saline lakes scattered over the pampas, the largest being the Mar de Chiquita, and Lake Porongos in Cordoba, the great swamps and lagoon on the lower Salado in Mendoza, and Lake Bebedero in San Juan.

The fauna of the pampas is limited to comparatively few species, all of which are found beyond its limits, also. These include the vizcacha (Lagostomus trichodactylus), Patagonian hare (Dolichotis patagonica), coypu (Myopotamus coypu), cui (Cavia australis), tucotuco (Ctenomys magellanica), jaguar (Felis onca), puma (Felis concolor), grass-cat (resembling Felis catus), wood-cat (Felis geoffroyi), a fox-like dog (Felis pajeros, Azara), aguar5. ('akin to  skunk, weasel (Galictis barbara), deer (Cervus campestris), four species of armadillo, and two of the opossum. Hudson considers the burrowing vizcacha, or biscacha, the most characteristic denizen of the pampas, though the large yellow opossum (Didelphys crassi. caudata) seems to be singularly adapted to life on the level grassy plain. The avifauna is apparently richer, owing to migration. Hudson enumerates 18 species of storks, ibises, herons, spoon-bills and flamingoes, 20 species of ducks, geese and swans, 10 or 12 of the rallines, including the graceful ypicaha or dancing bird, and 25 of the Limicolae (13 of which are visitors from North America). Land birds are not numerous. Vultures and hawks are common, and there are a few owls, the best known of which is the "minera" (Geositta cunicularia), which inhabits the burrow of the vizcacha. Among other species of land birds, some 40 in number, are the military starling (Sturnella), whose red breast makes it a conspicuous object on the pampas, the white-banded mocking-bird, the chakar or "crested screamer" (Chauna chavarria), the tinamou, and the rhea, or South American ostrich. There are two species of the tinamou - the rufous and spotted - which are called partridges and are often hunted with snares by horsemen. The rhea, once very numerous, is now found farther inland than formerly, and is steadily diminishing in number.

Civilized occupation is working many changes in the character and appearance of the pampas. The first change was in the introduction of cattle and horses. Cattle were pastured on the open pampas and were guarded by men called gauchos or mestizos, who became celebrated for their horsemanship, their hardihood and their lawlessness. Attention was then turned to sheep-breeding, which developed, another and better type of plainsmen - the Irish and Scotch shepherds. Then followed the extensive cultivation of cereals, forage crops, &c., which led to the general use of fences, the employment of immigrant labourers, largely Italian and Spanish, the building of railways and the growth of "camp" towns. The picturesque gaucho is slowly disappearing in the eastern provinces, and the herds and flocks are being driven farther inland. The rural population of the pampas is still sparse and the estancias are very large.

See W. H. Hudson, The Naturalist La Plata (London, 1895); Charles Darwin, Voyage of the Beagle (London, 1839 and 1889); and Richardo Napp, La republica argentina (Buenos Aires, 1876; also in German).