Urbanization degree rather than methanotrophic abundance decreases soil CH₄ uptake

Urbanization has been increasing worldwide, which can greatly influence ecosystem functions such as soil methane (CH₄) uptake. However, little information is available for quantifying the effects of urbanization on soil CH₄ uptake and the underlying microbial mechanisms. By conducting a meta-analysis of soil CH₄ uptake under urbanization worldwide in combination with measurements of potential soil CH₄ uptake from 134 samples along an urbanization gradient across Shanghai, China, we found that urbanization significantly decreased soil CH₄ uptake with greater inhibition under higher urbanization levels. Urbanization degree, index of urbanization levels, explained large variations of soil CH₄ uptake, and urbanization decoupled the relationships between methanotrophic abundance and soil CH₄ uptake, which was often neglected in previous research. To our knowledge, this is the first study to quantify the effects of urbanization degree on soil CH₄ uptake, which need to be incorporated into Earth system models for estimating the global CH₄ budget more accurately.