FOLIVORY LEVELS OF SEEDLINGS AND CANOPY TREES IN TROPICAL AND SUBTROPICAL RAINFORESTS IN AUSTRALIA

Abstract

Folivory levels were measured for seedlings and canopy trees of seven rainforest tree species (five in subtropical rainforest and two in tropical rainforest) in Queensland, Australia. Leaf damage was found, on average, to be higher for the subtropical species than for their confamilial tropical counterparts. Higher levels of damage than those reported here occur in neotropical rainforests, which suggests that high productivity may not mask folivore pressures in those systems. The latitudinal pattern of folivory established in this study, may consequently be unique to Australia. Comparisons of damage levels between seedlings and canopy trees (of the same species) indicate that in most cases seedlings suffer higher levels of damage. This result is presumably due to the longer leaf lifetimes of seedlings and the accumulation of damage over long periods of time. For subtropical tree species, measurements of leaf damage levels were taken twice, once in spring (November 1995) and once in autumn (March 1996). Observational evidence indicates that changes in leaf damage levels were related to species-specific leaf phenological patterns. The production of new leaves generally led to a reduction in the recorded measurements of leaf area lost, because the samples consisted of greater numbers of young leaves that had little opportunity to accumulate damage.