Root-derived CO2 flux from a tropical peatland

Tropical peatlands release significant quantities of greenhouse gases to the atmosphere, yet the relative contributions of heterotrophic and autotrophic respiration to net CO2 fluxes remains sparsely quantified. We used a combination of in situ trenching and vegetation removal in ex situ pots to quantify root-derived CO2 under two plant functional types within a mixed species forest. Trenching significantly reduced surface CO2 flux, indicating that approximately two-thirds of the released CO2 was derived from roots. In contrast, ex situ vegetation removal in pots indicated that root-derived CO2 accounted for 27% of the total CO2 flux for Campnosperma panamensis, a broadleaved evergreen tree, and 49% for Raphia taedigera, a canopy palm. The results show that root-derived CO2 is a major contribution to net CO2 emissions in tropical peatlands, and that the magnitude of the emissions is affected by plant species composition. This is important in the context of land use change driving alterations in vegetation cover.