The plant economics spectrum of litter decomposition Grégoire

SUMMARY (1) Recent evidence indicates tight control of plant resource economics over interspecific trait variation among species, both within and across organs. Here we demonstrate that this 'Plant economics spectrum' has important afterlife effects on carbon turnover by driving coordinated decomposition rates of different organs across species. (2) To that end, we conducted a common-garden decomposition experiment bringing together leaves, fine stems, coarse stems, fine roots and reproductive parts from a wide range of subarctic plant types, clades and environments and measured all plant parts for the same (green and litter) plant economics traits. (3) All organ decomposabilities were consistently controlled by the same structure-related traits (lignin, C and dry matter content) while nutrient-related traits (N, P, pH, phenols) had more variable influence, likely due to their contrasting functions across organs. Consistent shifts in elevation of parallel trait-decomposition relationships between organs indicate that other traits relating to organ dimensions, configuration or chemical contents co-determine litter decomposition rates. (4) While the coordinated litter decomposabilities across species organs imply a coordinated impact of plant aboveground and belowground litters on plant-soil feedbacks, the contrasting decomposabilities between plant parts suggest a major role for the relative inputs of organ litter as driver of soil properties and ecosystem biogeochemistry.