Marion Schmelz
Department of Palynology and Climate Dynamics, University of Göttingen, Alemania [marionschmelz@ewetel.net]
Late-Holocene Vegetation Dynamics of Batea Mahuida, northern Patagonia, Argentina
Knowledge about past vegetation dynamics is a useful tool in nature conservation. Araucaria araucana (Mol.) M. Koch is an endemic conifer of the Subantarctic forests of northern Patagonia. The species is symbolic for the region and of high cultural importance for the Mapuche. At present, it is declared an endangered species by the IUCN (International Union for Conservation of Nature) due to the limited distribution area and decreasing population densities. Little is known about the Holocene history of Araucaria araucana. Here, we reconstruct the late-Holocene development of the population of Araucaria araucana of the protected area Batea Mahuida, located in the Argentinean province of Neuquén. Fossil pollen, lithology and loss on ignition of a sediment core of Laguna Corazón (38°50’17.1 S, 71°05’41.6 W) were examined. The record was dated to represent the last 4000 years. Data indicate that during this time open steppe vegetation dominated in Batea Mahuida. Araucaria araucana has been associated with Nothofagus species, presumably Nothofagus pumilio and Nothofagus antarctica. The abundance of Araucaria araucana increases throughout the whole record, demonstrating its competitiveness in association with modern angiosperms. The relative abundance of Nothofagus forests in comparison to grassland decreases markedly under anthropogenic impact since the arrival of European settlers. Contrary to expectations, grazing and possible logging activities have no effect on population density of Araucaria araucana in Batea Mahuida discernible in the pollen record.