Ants in Burned and Unburned Areas in Campos Rupestres Ecosystem

Abstract

Ground-dwelling ants have shown consistent resilience to fire in savanna environments. We carried out a study to investigate how ant community structure responds to fire in a harsh and fragile Cerrado ecosystem, the campos rupestres. We studied the change in the ant communities on a local scale subjected to fire in two rocky outcrop habitats at two different elevations (800m above sea level and 1300m a.s.l.). Pitfall trap samples were set at three different periods after a fire event: one, four, and ten months later. Overall, one hundred and fifteen ant species were collected. On a local scale, at the altitude of 800 m asl, no difference in richness and composition of the ant community was found between burned and control plots, whereas at 1300 m asl the burned areas showed higher richness and different ant composition in comparison to control areas. Differences were clear in the rainy period, four months after the fire. Ten months later, no difference between the richness of ant species in burned and unburned plots was found at higher altitudes, even though the plots showed distinct species composition. These data support the hypothesis that fire must be a structuring disturbance factor for some groups in the ant assemblages and indicate that ant community structure at higher elevations is somehow influenced by the recover of the campos rupestre vegetation.

Monitoring Effect of Fire on Ant Assemblages in Brazilian Rupestrian Grasslands: Contrasting Effects on Ground and Arboreal Fauna

“…Second, the change in relative abundances of the four most frequent species on the ground was much greater in the burnt than unburnt area ( Pheidole reflexans — (mean ± SD) burnt: 17.20 ± 31.56, unburnt: 7.66 ± 10.52; Camponotus crassus —burnt: 5.30 ± 8.40, unburnt: 2.00 ± 1.10; Camponotus rufipes —burnt: 8.23 ± 15.69, unburnt: 3.60 ± 2.52; Pheidole sp2—burnt: 10.65 ± 16.39, unburnt: 1.66 ± 0.81). Strong effects of fire on ant composition (i.e., changes over time) were also reported in two other studies of fire ants in rupestrian grasslands [ 15 , 16 ].…”

“…The absence of fire effects on cumulative species richness can be explained by several factors. First, based on the long geological time that ants have inhabited fire-prone environments such as the Brazilian savanna [ 12 , 14 , 36 ] and rupestrian grasslands [ 15 , 16 ], we expect these insects to be highly resistant and resilient to fire. Areas with shorter vegetation stature (e.g., rupestrian grasslands) are dominated by ants that nest in the soil, protected from direct effects of fire.…”

“…This fact may partially explain the higher mean species richness and abundance of ants in the burnt area in the second year of the study ( Figure 3 A and Figure 4 A). In another study of rupestrian grasslands in southeastern Brazil, mean species richness and abundance of ground ants increased four months after a fire event [ 16 ].…”

“…With respect to the impacts of fire, ants are one of the best-studied animal taxa [ 12 , 13 , 14 , 15 , 16 ]. In fire-prone habitats—such as the tropical savannas of Australia, Africa, and South America—the natural regime (higher frequency and lower intensity) can increase the structural diversity of vegetation, generating long-term positive effects on ant diversity [ 14 , 17 , 18 ].…”

“…On the other hand, forest studies have shown strong and negative consequences of fire (e.g., fire from human activities) on ant diversity at all spatial and temporal scales [ 19 , 20 , 21 ]. With regards to the rupestrian grasslands, there is little information about effects of fire on ant communities (but see [ 15 , 16 ]). Our expectation is that ant community responses to fire are likely more similar to those typical of savanna than to forest habitats [ 16 ], as rupestrian grasslands possess floristic and landscape features that are more similar to Brazilian savanna than Atlantic forest [ 3 ].…”