Response of methanotrophic communities to afforestation and reforestation in New Zealand

Methanotrophs use methane (CH 4) as a carbon source. They are particularly active in temperate forest soils. However, the rate of change of CH 4 oxidation in soil with afforestation or reforestation is poorly understood. Here, soil CH 4 oxidation was examined in New Zealand volcanic soils under regenerating native forests following burning, and in a mature native forest. Results were compared with data for pasture to pine land-use change at nearby sites. We show that following soil disturbance, as little as 47 years may be needed for development of a stable methanotrophic community similar to that in the undisturbed native forest soil. Corresponding soil CH 4-oxidation rates in the regenerating forest soil have the potential to reach those of the mature forest, but climo-edaphic fators appear limiting. The observed changes in CH 4-oxidation rate were directly linked to a prior shift in methanotrophic communities, which suggests microbial control of the terrestrial CH 4 flux and identifies the need to account for this response to afforestation and reforestation in global prediction of CH 4 emission.