Abiotic drivers of heterotrophic soil respiration 1 Short-and long-term influence of litter quality and quantity on simulated heterotrophic 2 soil respiration in a lowland tropical forest 3 4 5

10 11 1) Heterotrophic soil respiration (SRH) alone can contribute up to 50% of total ecosystem 12 respiration in tropical forests. Whereas the abiotic controls of SRH have been extensively 13 studied, the influence of plant traits is less well characterised. 14 2) We used field experiments and a modelling approach to test the relative influence of 15 plant traits on SRH in lowland tropical forest in French Guiana. We measured leafand root 16 litter traits for five common tree species and conducted a root decomposition experiment to 17 evaluate the influence of root chemistry on decay rates. We measured SRH in trenched plots 18 and used our field measurements to parameterize and test the Century model of soil C 19 dynamics. 20 3) Overall, the Century model performed well in simulating SRH and species-specific 21 root decomposition in Century corresponded well to decomposition rates measured in situ. 22