Use of a logging road in a Costa Rican forest changes the composition and stability of soil microbial decomposer communities, and the conversion of organic carbon into biomass.

This article examines the impact of a logging road constructed after Hurricane Otto on soil carbon (C), nitrogen (N), and the compositions of three key microbial decomposer communities—Actinobacteria, Acidobacteria, and wood rot/lignin-degrading (WRT/LD) fungi—in a Costa Rican old growth tropical forest. Using soil samples collected before and up to four years after road abandonment, the study found that the logging road significantly reduced soil total organic C, respiration, biomass C, and total N, while altering microbial communities from stable copiotrophic taxa in forest soils to oligotrophic taxa in disturbed soils. The Actinobacterial and Acidobacterial communities showed signs of taxonomic stabilization over time, indicating adaptation to altered soil conditions, whereas the WRT/LD fungal community exhibited ongoing taxonomic divergence and decreased stability, suggesting a prolonged decline. These microbial shifts correlated with changes in soil C and N metrics, highlighting their potential as indicators for assessing soil ecosystem damage and recovery in tropical forest management.