Boreal wetlands play an important role in global carbon balance but their ecosystem function is threatened by direct and regional anthropogenic disturbance and climate change. Oil sands mining in boreal Canada leaves large areas in need of reclamation and generates considerable quantities of extraction‐process‐affected materials. It is important to know whether reclaimed wetlands are restored to equivalent ecosystem function. We approached this by assessing carbon flows and food web structure in oil‐sands‐affected wetlands to evaluate whether a prescribed reclamation strategy, topsoil amendment, accelerates reclaimed wetland development leading to self‐sustaining peatlands. We determined carbon fluxes and measured compartment standing stocks for residual hydrocarbons, organic substrate, bacterioplankton, phytoplankton, biofilm, macrophytes, detritus, zoobenthos and aquatic‐terrestrial exports (i.e. aquatic insect emergence). Most biotic compartments differed between oil‐sands‐affected and reference wetlands. This difference declined with age since construction but was still detectable in older (15‐20 y) wetlands. Macroinvertebrate trophic diversity was lower in oil‐sands‐affected wetlands. Peat amendment appeared to speed convergence for some compartments but not others. We discuss results in the context of restoration of ecosystem function and optimization of reclamation strategies.