How do patch burnings affect ant communities and seed removal in a subtropical grassland?

Abstract

Disturbances modify local abiotic properties, habitat structure and resource availability, shaping community assembly and ecological interactions. Open ecosystems have an evolutionary relationship with fire. We evaluated the effects of patch burnings on grassland ant communities and patterns of seed removal. We established 14 plots of 10 m2 in pairs in a disturbance-suppressed grassland in South Brazil. A random plot of each pair was burned, and another plot was the control. We accessed ant communities with pitfall-traps and sweeping net, and seed removal with seed traps in all plots prior the experimental fires, and then on three occasions following fires. We recorded 57 ant species belonging to 29 genera. Ant species composition did not significantly vary between treatments neither did ant body size. We detected significantly positive fire effects on ant richness after 1 month and 12 months, mediated by the increase in plant species richness in burned plots. Mean seed removal rates were increased in burned plots after 1 month. We showed that prescribed patch burnings in fire-prone grasslands promoted ant richness, and their foraging activity. Our study may serve as a basis for conservation decisions, showing the importance of maintenance of disturbances in grasslands.

Keywords

• Fire effect
• Resource removal
• Ant body size
• Disturbances
• Campos Sulinos