Responses of soil cellulolytic fungal communities to elevated atmospheric CO2 are complex and variable across five ecosystems

Summary Elevated atmospheric CO2 generally increases plant productivity and subsequently increases the availability of cellulose in soil to microbial decomposers. As key cellulose degraders, soil fungi are likely to be one of the most impacted and responsive microbial groups to elevated atmospheric CO2. To investigate the impacts of ecosystem type and elevated atmospheric CO2 on cellulolytic fungal communities, we sequenced 10 677 cbhI gene fragments encoding the catalytic subunit of cellobiohydrolase I, across five distinct terrestrial ecosystem experiments after a decade of exposure to elevated CO2. The cbhI composition of each ecosystem was distinct, as supported by weighted Unifrac analyses (all P‐values;