INVESTIGADORES
KITZBERGER Thomas
congresos y reuniones científicas
Título:
Ontogenetic changes in tree insect herbivory and foliar traits in dry and wet southern beech Patagonian forests
Autor/es:
MAZ√ćA, C.N.; GARIBALDI, L.A.; CHANETON, E.J.; KITZBERGER, T.
Lugar:
Bariloche
Reunión:
Congreso; VI Southern Connection Congress; 2010
Institución organizadora:
Southern Connection
Resumen:
As plants pass through successive life stages, marked changes occur in apparency, structural complexity and nutritional quality, which can influence susceptibility to herbivory. Based on different assumptions different models make contrasting predictions about herbivore responses to changes in host traits among age-size classes. Yet, there have been few tests of the effect of ontogeny on herbivory, especially in forests. We examined folivory by different insect guilds on three age-size classes of Nothofagus pumilio trees, in dry and wet forests of northern Patagonia, Argentina. We sampled the canopy of saplings (< 1m tall), juveniles (3-4 m) and adult trees (>10 m), and measured physical and chemical leaf traits for each plant (n = 14). Early in the growing season, leaf damage was higher in saplings and juveniles than in adult trees in both forests, and remained so later in the season in the wet forest. In contrast, in the dry forest, insect damage markedly increased at the end of the season on adult trees, which blurred earlier differences among age classes. There were significant, habitat-specific differences in foliar traits among tree classes, but these could not account for herbivory patterns in either forest. Overall, we found partial support for the hypothesis that insect herbivory declines as trees grow from a deep understorey layer into the upper forest canopy. However, ontogenetic changes in folivory appeared to depend on the forest habitat.