PALEOECOLOGY OF A DONATIA-ASTELIA CUSHION BOG, MAGELLANIC MOORLAND-SUB-ANTARCTIC EVERGREEN FOREST TRANSITION, SOUTHERN TIERRA-DEL-FUEGO, ARGENTINA

Cushion bogs are an integral feature of Magellanic Moorland of subanta rctic, southernmost Chile (48-56 degrees S). The palaeoecology of an o utlying cushion-type bog at Bahia Moat, located in moorland-forest veg etation on the southeastern coast of Argentine Tierra del Fuego, trace s the 7000 yr development of the site, local and surrounding vegetatio nal history, and palaeoclimate. Pollen and spore stratigraphy indicate s that cushion plants, Donatia and Astelia, characterized the bog over the past 2600 yr. Regional vegetation became forest-dominated after 4 750 yr BP, following displacement of open communities of Gramineae and Compositae by the evergreens Nothofagus betuloides and Drimys winteri . Increased precipitation/evaporation ratios in effect during the late Holocene were coupled with lower temperatures, contrasting less humid , moderated conditions with high fire incidence prevailing early in th e bog record.