Plant Diversity Mitigates the Effects of Urbanization on Soil Organic Carbon Stocks

Urbanization is increasing worldwide, which have considerable consequences on ecosystem functions such as soil carbon (C) sequestration, however, the underlying microbial mechanisms regulated by plant diversity of urbanization on forest soil organic C stocks (SOCs) is still unclear. In this study, plant diversity along an urban-suburban-rural gradient and its relationships with the activities of micro-enzymes and the SOCs were quantified. We found that urbanization significantly reduced SOCs in surface soils via changing temperature, soil C: P ratios, and the relative abundance of key enzymes for C sequestration and degradation. Plant diversity showed significant and positive effects on SOCs via affecting soil C: P ratios and microorganisms. The greater effects of plant diversity than those of urbanization on SOCs imply that plant diversity can mitigate the negative effects on soil C sequestration in the context of global warming, which provides a sound theoretical basis for effectively improving forest quality and ecological functions.