Modeling Decomposition: Beyond a Well-Mixed World

Carlos A Aguilar-Trigueros, William K Cornwell, Katherine Rocci, Baptiste Joseph Wijas, Amy E Zanne

Carbon cycle models overlook resource patchiness and networked foraging characterizing terrestrial carbon dynamics. They treat inputs as well mixed and decomposers as acting at local scales, making substrate stoichiometry, rather than spatial access, the primary constraint on decomposition. Using deadwood decomposition by cord-forming fungi and termites as examples, we illustrate how resource patchiness and networked foraging are large carbon cycle components departing from well-mixed expectations. Deadwood patchiness limits decomposition in organisms incapable of integrating distant substrates. Fungal and termite transport networks alleviate these constraints connecting substrates across space and time, altering deadwood decomposition, decomposer biomass and necromass turnover rates. We outline bottom-up and top-down approaches coupling network foraging and transport models to carbon models, moving the field beyond well-mixed paradigms.