CO2 emission from subterranean nests of ants and termites in a tropical rain forest in Sarawak, Malaysia

- Nest CO2 emission was higher than those from surrounding bulk soil.
- Soil moisture content was lower in ant nests than in control soil.
- Impact of soil temperature and moisture content on nest CO2 emission was unclear.
- Nest CO2 emission was different among ant and termite species.

Ants and termites are highly abundant in tropical forest soil, but their role in soil CO2 emission is poorly understood. Our goal in this study was to determine the CO2 emission from nests of ants and termites in a tropical rainforest in Sarawak (Borneo), Malaysia. The study was conducted in Lambir Hills National Park, Miri. We located nests of ants and termites and measured CO2 emission from the nests and from the surrounding control soils. Soil temperature and moisture content were also recorded at the nests and control soil locations. The ants and termites were identified to genera (and to species in many cases) and their body mass was determined. In total, we found 113 nests of 36 ant species and 20 nests of 10 termite species. CO2 emission from ant and termite nests was significantly higher than that from the surrounding soils, suggesting ant and termite nests are hot spots of CO2 emission from the soil. Because of nesting activities, soil moisture content was significantly lower in ant nests compared to that of the control soils. The effect of soil temperature and moisture content on nest CO2 emission was less clear when compared to emission from the surrounding control soils. Significant differences in nest CO2 emission were observed between different ant species, which could be partly attributable to differences in body mass.