Decomposition of 51 semidesert species from wide-ranging phylogeny is faster in standing and sand-buried than in surface leaf litters: implications for carbon and nutrient dynamics

Higher than expected litter decomposition rates have been observed in dry, sunny environments due to photochemical or physical degradation. However, our understanding of carbon and nutrient fluxes of standing and buried litters compared to surface litter in such areas is still scarce. We sampled leaf litters from 51 species in a semiarid dune ecosystem and incubated them in three positions: surface, sand-buried and simulated standing. Decomposition was much faster in buried litter and somewhat faster in simulated standing litter than in surface litter. This pattern was independent of the incubation period, phylogenetic group or growth form. Litter position and incubation period significantly impacted litter nutrient dynamics. The nitrogen (N) and phosphorus (P) losses were faster in buried and simulated standing litters than in surface litter. The N loss was slower than P loss in 6-month decomposed litter but the former was relatively faster than the latter in the second phase up to 12 months of incubation. Our study shows that substantial mass and nutrient losses in simulated standing and buried litters can be a candidate explanation why drylands have higher carbon and nutrient fluxes than expected based on surface litter decomposition data alone