Abundance of epigaeic arthropods in a Brazilian savanna under different fire frequencies

Abstract

ABSTRACT. Fire is a major determinant of structure and dynamics in savannas, and the rapid increase of human activities inthis biome has changed the natural burning regime. The effects of fire on the fauna of the cerrado (Brazilian savanna) arestill poorly understood, and studies comparing sites frequently and infrequently burned are scarce. In this study, theabundance of epigaeic arthropod orders and trophic guilds was assessed in cerrado sites located in the Brazilian CentralPlateau that were subjected to three burning frequencies: frequent (HighFi), intermediary (MidFi), and infrequent (LowFi).In general, we found a positive relationship between the abundance of epigaeic arthropods and fire frequency. Whenarthropods were analyzed by orders, the abundance of Collembola and Orthoptera was lower in the LowFi site, while forHemiptera, it was higher in the MidFi site. No significant differences were found for Hymenoptera, Coleoptera, and Araneae.The abundance of detritivores and herbivores decreased from HighFi to LowFi, but did not change significantly for omni-vores and predators. These results indicate that some arthropod groups may not only be resilient to fire effects, but actuallymight benefit from fire effects in the cerrado. Characterizing arthropod responses to burning frequency at high taxonomicor functional levels is important for applied studies. Based on the results of the current study, springtails and ants seem tobe particularly appropriate focal groups for further exploratory studies on the effects of fire at the species level.KEY WORDS. Arachnida; burning; cerrado; Insecta; trophic guilds.