Shrubification of peatlands

Biogeography Soil is a key player in the global carbon cycle. Peatlands are important because they contain more than half of global soil carbon, much of which is sequestered in slow-decaying Sphagnum moss. Hence, there is a need to understand how peatlands will respond to the rapidly changing climate. Malhotra et al. assessed the response of plant roots to experimental warming in a peatbog ecosystem in the state of Minnesota, United States. The growth of fine roots of shrubs and trees over two growing seasons rapidly increased by 130% for each 1°C temperature increase, mainly because of the drying of the soil and the increase in the duration of the growing season. The authors suggest that over the longer term, drying will allow replacement of Sphagnum moss by other plants and hasten the loss of soil carbon. Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.2003361117 (2020).