Modelling the effects of litter decomposition on tree diversity patterns

Current theories may not fully explain why latitudinal patterns of plant diversity differ between terrestrial and flooded ecosystems. Moreover, the co-occurrence of hyper diverse stands in lowland tierra firma (not inundated) forests and almost monospecific stands in mangroves and gallery riparian vegetation within the tropics remains enigmatic. Building on evidence from ecology and agriculture, we present a new model investigating the hypothesis that, besides the general positive feedback of plant growth by nutrients release, litter decomposition builds up an intra-specific negative feedback functionally linked with tree diversity. The model results were compared with extensive published data sets both across and within latitudinal zones. The model predicts correctly the biomass production and decomposition process, as well as the number of tree species, their relative abundance in all environmental conditions providing a novel, putative explanation also for the diversity variations observed within the tropics. The model demonstrates a possible mechanistic link between the carbon cycle and biodiversity patterns, which is interesting in the debate about advancing in the direction of a unifying ecosystem theory.