ncreasing Ages of Inga punctata Tree Soils Facilitate Greater Fungal Community Abundance and Successional Development, and Efficiency of Microbial Organic Carbon Utilization

Leguminous Inga trees are thought to enhance soil carbon (C) accumulation following reforestation through mostly unknown mechanisms. This study amplified soil DNA using the ITS1F and ITS4 primers for PCR and Illumina MiSeq methods to identify fungal taxa, and traditional C analysis methods to evaluate how planted 4, 8, 11-year-old, Inga punctata trees affected soil fungal community compositions and C utilization patterns compared to old growth I. punctata trees and adjacent unplanted pasture within the same reforestation zone in Monteverde, Costa Rica. Along the tree age gradient the planted I. punctata trees enhanced the tree soil C-capture capacity as indicated by increased levels of soil Biomass-C, Respiration, and efficiency of organic C use (as lower qCO2 values), and development of increasingly more abundant, stable and successionally developed fungal communities, including those associated with decomposition of complex organic C compounds. The level and strength of differences coincided with differences in time of separation between the pasture and tree age or between the different tree ages. Fungal taxa were also identified as potential indicators of early and late stages of soil recovery. Thus, planting I. punctata should be part of future reforestation strategies used in this region of Costa Rica.