Magnitude and drivers of greenhouse gas emission from ant nests

Abstract

Greenhouse gas (GHG) emission is a worldwide concern, making the identification of emission sources and their magnitude an urgent issue. Ants release large amounts of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from their nests. Beyond the already known anthropogenic sources of CO2 emissions, such as fossil fuel combustion in the power generation, industrial, residential, and transport sectors, the evaluation of GHG emissions from ant nests is a current research target. However, there are still gaps regarding the real impact of ant nests on GHG emission, primarily because most surveys were conducted excluding anthropogenic areas. In the present study, we aimed to fill part of these gaps by evaluating the magnitude and drivers of GHG emission from ant nests. Our results were organized over three chapters. First, chapter I discussed the current scenario and highlighted the methodological issues of the studies on GHG emissions from ant nests using a systematic review as methodology. We present a scientometry of available publications, which revealed the lack of investigations of ant nests emission in anthropogenic areas and on countries that are higher sources of anthropogenic GHG. Second, in Chapter II, we’ve made a methodology test related to the closed chamber method, guided by some warnings which stood out in the systematic review. Results revealed a dilution effect of the soil surface over the CO2 measurements when using chambers whose diameters are significantly larger than the nest hole. Finally, in Chapter III, we’ve made field measurements of CO2 emissions from Acromyrmex subterraneus nests in urban areas, considering the effect of features of the nest. This investigation revealed an association of CO2 flux with the function of the nest hole, a component of ant nests not yet investigated. Obtained results also showed that ant nests are on a par with recognized anthropogenic CO2 sources, adding one more point to consider in the context of climate change, considering the facility of installation of some ant species in urban and disturbed areas. We hope that these results contribute to expanding knowledge regarding the role of ant nests in CO2 emissions and could even guide the next steps for future investigations.