Differences in the soil microbial community and carbon use efficiency following development of Vochysia guatemalensi s tree plantations in unproductive pastures in Costa Rica

This study shows that Vochysia guatemalensis tree plantations were associated with enhanced soil biotic and abiotic characteristics in previously cleared forests in the northern zone of Costa Rica, suggesting the possible use of this practice as a restoration strategy for local land owners. Soil samples from a primary forest, secondary forest, and a 13-year-old plantation of V. guatemalensis had greater relative abundances of DNA sequences of microbial genera critical for carbon-use (C-use) efficiency (i.e. the saprobe, complex C and wood rot/lignin decomposer fungi, and bacterial lignin and other complex C degraders), and greater levels of total organic carbon, C-biomass, and microbial quotients as indicators of enhanced C-use efficiency, than found in soils of adjacent 5-year-old V. guatemalensis plantations and abandoned non-productive pasture/grasslands (GRs). The major research conclusions were that (1) conversion of forested land into abandoned pasture/GRs decreased the C-use efficiency in the soils and the microbial groups associated with C-use efficiency; (2) soils in plantations of V. guatemalensis were associated with increased abundances of the DNA of these same microbial groups and enhanced C-use efficiency; (3) DNA-based taxonomic analysis of microbes and analysis of the microbial quotient values can be used to monitor soil ecosystems for assessment of the efficacy of restoration activities. Thus, planting V. guatemalensis on damaged lands in the Maquenque National Wildlife Refuge should be encouraged to provide a sustainable forestry crop that can be harvested rotationally, while improving soil ecosystem health and reducing the pressure to harvest other forest sites.