Quantifying invertebrate-mediated herbivory across an anthropogenic disturbance gradient in amazonian forests

Abstract

Disturbance is a generalized threat to biodiversity, indirectly impacting ecological interactions with possible far-reaching consequences for tropical forests. Herbivory is a key ecological interaction being an interesting field to explore specially in human-altered tropical rainforests, with the potential to unravel critical consequences for both herbivores and forest ecosystems. We demonstrated in a large-scale study that, despite current rates of disturbance and negative effects on diversity, these impacts not necessarily extend to ecological interactions. We found these Amazonian forests herbivory levels to be dominated by chewing and the other two forms of invertebrate–mediated herbivory surveyed (mining and galling) followed both with relatively very low incidence dominated herbivory levels. No overall changes in herbivory levels along disturbance in Amazonian forests surveyed, with a weak link between herbivory and environmental disturbance variables. Tropical forest landscapes are suffering unprecedented rates of disturbance and we found evidences slight effect of light pressures of disturbance, we claim implications for conservation policies to focus on maintenance of functionality of ecological processes outcomes such as herbivory and encouraging monitoring of these. Herbivory not only seem to be functionally resistant to disturbance, but also play critical role on forest regeneration, contributing in several ways to forest resilience as a whole. Our results bring insights for tropical forest functioning since drivers of environmental change that affect biodiversity are likely to result on long-term ecosystem impacts.