Greenhouse gas emissions from termite mounds in a transition area between the Cerrado Savanna and the Atlantic Forest in Brazil

The contribution of termites to the global balance of greenhouse gases, which is aggravated by large seasonal variations in their emissions, remains unclear. The objectives of this study were to evaluate the influence of termite mounds on CH4, CO2 and N2O emissions and to analyze their diurnal variations over a 9-month (249-day) period in a transition area of the Cerrado Savanna and Atlantic Forest biomes in Brazil where the current land use was a non-managed pasture. We used transects to estimate greenhouse gas emissions across the study area. The results revealed that soils settled by termites emitted more CH4 than they consumed, exhibiting 113% higher CH4 emissions than soils without termites, which emitted an estimated 10.09 g of CH4 ha (-1) day(-1) on average. The wood-feeding Cornitermes sp., the most abundant species in the mounds area analyzed in the experiment, accounted for 83.12% and 83.09% of the CH4 and CO2 fluxes. Extrapolating our results to non-managed Brazilian pastures, CH4 emissions arising termite mounds could reach up to 6.25 Tg ha(-1) yr(-1). The results of this study reveal that tropical pastures in transition areas between Cerrado and Atlantic Forest biomes infested by termite mounds can greatly contribute to increased CH4 emissions and should be considered in the inventory of greenhouse gas emissions.