congresos y reuniones científicas
Patterns of cone production, seed predation and seedling establishment in the large-seeded Araucaria araucana
SANGUINETTI, J.; KITZBERGER, T.
Congreso; VI Southern Connection Congress; 2010
Spatio-temporal patterns of cone production, seed predation and seedling establishment were studied in Araucaria araucana. With cone production and seed gathering data we covered up to 18 years from 12 sites in an area of more than 7600 km2 in Neuquén Province (Argentina). Predation, seed survival and seedling establishment were measured during 2004-2008 at different microsites from 11 isolated trees in A. araucana and Nothofagus pumilio or N. antarctica mixed forest, where native rodents and exotic wild boar are abundant. Long term regeneration was also studied. A. araucana showed an environmentally triggered, intermittent, moderately fluctuating and highly regional synchronous masting. Wild boars ate up to 45 % of available seeds on a 13-day period vs. 30 to 60% eaten by rodents, and seem to affect the individual fitness of mother trees. Rodent predation was high at dense vegetation, while wild boar predation was moderate at poorly vegetated microsites. A. araucana showed a pulse of seedling establishment, synchronized among trees and associated with masting where a 5 fold increase on seed survivorship occurred. Under Chusquea bamboo cover seedling regeneration was strongly inhibited by granivory. We conclude that A. araucana regeneration seems to be mainly controlled by seed production, but granivory modulate the intensity of seedling establishment. Pollination efficiency and predator satiation may have shaped the reproductive strategy of this unique tree.