Restored lowland heathlands store substantially less carbon than undisturbed lowland heath

The conversion of lowland heathland to agricultural land in Europe significantly depleted soil carbon stocks. Restoring heathlands has been proposed as a mechanism to sequester soil carbon. Here we compared soil carbon in (i) agricultural pasture; (ii) native heathland and (iii) restored heathland through acidification with elemental sulfur (sulphur). After 18 years of soil acidification, soil chemical properties (pH, extractable nutrients etc.), fauna and vegetation assemblage resembled that of native heathlands. However, native heathland was found to contain more than double the soil carbon stock of restored heath, with significantly higher contents of stable soil organic matter, and restored heath soil carbon was not significantly different to the control pasture. This result, combined with supporting findings of a comprehensive literature review, has ramifications for carbon-sequestration proposals, given the urgency required for climate mitigation tools.