Low methane emissions following experimental bog rewetting

Peatlands cover only 3–4% of the world’s land surface, but store one-third of global soil carbon. Undisturbed peatlands act as long-term net carbon sinks, but draining peatlands can convert them into net sources of greenhouse gases. Rewetting drained peatlands can improve CO 2 sequestration; however, there is concern that rewetting produces additional CH 4 . Our experimental bog restoration project found that rewetting drained peat resulted in only a modest increase in CH 4 emissions, which was still lower than undrained natural peat at similar water table levels. We also saw an increase in CO 2 uptake. We hypothesize that peat chemistry is limiting CH 4 emissions after rewetting, with strong differences between the peat’s physical and chemical characteristics in the rewetted vs. reference treatments. Our results, and others, indicate that rewetting drained peatlands will likely increase CH 4 efflux, but post-restoration emissions typically remain below those of naturally occurring peatlands, suggesting that CH 4 concerns are not necessarily a barrier to restoration if done correctly.