La vegetación de las dunas marítimas de América Latina

Abstract

SUMMARY Dune and sand beach vegetation undergo stressing conditions of sand accumulation and removal caused by waves and wind. Thus, this vegetation is poor, more vulnerable, and uniform than that which grows in equilibrium with climate, soil and human influence. Moreover, along the coastal edge of Latin America climatic regions ranging from temperate to tropical and from perhumid to perarid are found. The history of Latin American flora, covers regions that are as far apart and different as the Atlantic and Pacific coasts. As a result, where the latitudinal direction prevails in the coastal line, vegetational units with little floristic variety are found. On the other hand, differences in coastal vegetation with meridional extension according to climatic zonations are notorious in the Atlantic as well as in the Pacific. The movile marine dunes of Latin America belong to the following classes of vegetational communities: Canavaletea maritimae: Atlantic beaches and dunes with tropical climate, from the Caribean to western Brazil; also found in the tropical Pacific coast of the Tehuantepec Gulf. Panicetea racemosi: Atlantic dunes with intense sand accumulation and removal, from the perhumid subtropical climate of western Brazil to the humid temperate coast of Argentina (Prov. of Buenos Aires-NE). Panico urvilleani-Sporoboletea rigentis: Dunes of the Atlantic coast with a temperate arid and subarid climate, from the south of the Prov. of Buenos Aires to the of Chubut. Ambrosietea chamissonis: From the Pacific beaches and dunes with temperate perhumid climate of the south in four associations of Polygonion sanguinariae to the arid subtropical small north of Chile; Ambrosion umbellatae to the of the tropical Pacific coast from Baja California to Vancouver. The need to create reservations to protect the biocenosis of the dunes, with no economical value but of great scientific interest, great beauty in their relief, flora and fauna is urgent.