Fire‐driven forest degradation enhances termite activity and accelerates litter decomposition in the Amazonia rainforest

Abstract Recurrent fires, combined with other disturbances, can severely degrade tropical rainforests. These disturbances alter abiotic conditions such as temperature, moisture and soil organic matter, which may affect termite communities and ecosystem processes. We investigated whether the indirect effects of fire in forests influence termite communities and organic matter decomposition and explored the mechanisms involved. We quantified ecological processes across undisturbed and degraded forests: (1) the relative contributions of invertebrates—particularly termites—and microorganisms to litter decomposition; (2) the relationship between termite abundance and litter decomposition; and (3) the top‐down regulatory effects of ants on termite communities. We took advantage of a long‐term fire experiment in southeastern Amazonia, comprising annually burned, triennially burned and an unburned forest recovering over a decade. Litter decomposition in burned forests was approximately 1.7 times higher than in unburned forest. In burned forests, decomposition was twice as high under invertebrate‐access treatments compared to microbes‐only treatments. In contrast, no difference was observed between invertebrate‐ and microbe‐driven decomposition in unburned forests. These results suggest a more significant role of invertebrates—especially termites—in litter decomposition in degraded forests than in undisturbed ones, while microbial decomposers appear able to compensate for the absence of termites only under undisturbed conditions. Higher litter decomposition was associated with increased termite abundance and reduced ant predation in annually burned plots. These findings suggest that forest degradation is associated with increased termite abundance and activity, potentially accelerating organic matter decomposition and improving soil conditions. Such changes may facilitate forest recovery through cascading effects on nutrient cycling and seedling establishment.