Fire affects galling insect communities through vegetation changes in a subtropical seasonally semiarid forest

Abstract

Fire is one of the main factors shaping vegetation characteristics around the world, with deep and complex effects on higher levels of the food web and ecosystem functioning. Specialist insects tend to be more vulnerable to fire than generalists due to their higher dependency on host plants; however, fire effects on specialist insects are still not clearly known. Our aim was to understand how fire-induced changes in plant richness and floristic composition modulate community features of galling insects under different fire scenarios. Specifically, we address the following questions: Are changes in galling insect richness and herbivory explained by the variation in plant richness and floristic composition under different fire scenarios? Are species composition of vegetation and galling insect communities coupled under different fire scenarios? Species richness of plant and galling insect communities was higher in burned than in unburned plots, but the highest species richness was observed under different fire scenarios in both communities. Galling insect richness was better predicted by floristic composition than plant richness. Herbivory was similar under different fire scenarios and weakly related to plant richness and composition. Species composition of vegetation and galling insect communities was strongly coupled across different fire scenarios. The characteristics of galling insect communities were strongly affected by fire through vegetation changes, and were better explained by floristic composition than by plant richness. Our results highlight the importance of selecting areas under different fire scenarios to maximise biodiversity conservation.