Abstract:
Herbivores play a key role for ecosystem functioning, but the current destruction of late-successional primary forests might negatively affect herbivore-mediated ecosystem processes. Understanding herbivore patterns between different succession stages is crucial for setting conservation priorities. Here we examined insect herbivore biomass and functional community
composition along a successional gradient in a tropical montane rainforest in southern Ecuador. The insects were sampled off
42 tree individuals via canopy fogging. The trees comprised three succession stages (9 early, 25 intermediate, 18 late) and 16 species. Insect herbivores were identified on order level and assigned to one of three feeding guilds (leaf chewers, rostrum chewers, sapsuckers). Overall, we collected almost 16 000 herbivore individuals. Herbivore dry mass was not significantly affected by tree succession stage for almost all groups surveyed, except for caterpillars which weighed less on late- than on early-successional tree species. Furthermore, herbivore community composition was neither explained by tree succession stage nor by tree phylogeny. We conclude that solely conserving forests of late succession is not always expedient and that factors need to be identified which predict herbivory and herbivore community composition in tropical montane rainforests.
