Above- and below-ground termite biomass and abundance in the Caatinga dry forest region

Termites are key decomposers and ecosystem engineers, strongly influencing nutrient cycling and soil structure in dry tropical ecosystems. However, their vertical distribution and the relative contribution of above- and below-ground compartments to total biomass and abundance remain poorly understood in semiarid environments. Here, we quantified termite biomass and abundance across seven Caatinga sites in northeastern Brazil using four complementary sampling methods: wood sampling, litter collection, nest excavation, and soil monoliths (0–30 cm). In total, 38.450 individuals were collected, representing 43 species across three families. Mean biomass reached 0.189 ± 0.042 g·m⁻² above ground and 1.352 ± 0.328 g·m⁻² below ground, while corresponding abundance were 272.5 ± 56.1 ind·m⁻² and 538.4 ± 121.1 ind·m⁻², respectively. Both biomass and abundance differed significantly between dry and wet seasons, with the upper soil layer (0–10 cm) concentrating nearly half of all individuals. Below-ground compartments accounted for termite biomass values approximately 7.1 times higher than those recorded above ground, indicating that the soil is the main reservoir of termite activity and carbon turnover in the Caatinga. Our findings demonstrate strong spatial and seasonal structuring of termite communities and emphasize the importance of incorporating vertical habitat heterogeneity in biomass assessments. By linking abundance, biomass, and soil depth, this study provides one of the most detailed quantitative assessments of termite assemblages in tropical dry forests, highlighting their key role in below-ground ecosystem functioning. • We estimated termite biomass and abundance across four microhabitats • Mean termite biomass was 1.541 ± 0.370 g m⁻² and varied seasonally • Mean termite abundance reached 810.9 ± 177.3 individuals m⁻² • Termite quantitative data were sensitive to both season and microhabitats • Below-ground compartments represented the largest biomass reservoir