Constant isometric scaling of soil carbon to nitrogen in Moso bamboo-invaded evergreen broadleaf forests in subtropical China

Elemental stoichiometry is crucial for the functioning of biogeochemical cycles. However, it is unclear how the invasion of Moso bamboo (Phyllostachys edulis) into evergreen broadleaf forests influences soil C and N stoichiometry. In the present study, we aimed to investigate how bamboo invasion affects soil C and N content, C:N ratio, and their scaling relationship at a large scale.

We collected 1,098 soil samples from 90 invasive transects using pairwise sampling across three forest types (bamboo, mixed bamboo and broadleaf, and evergreen broadleaf forests) at 30 sites in China's major bamboo distribution areas.

Bamboo invasion significantly decreased the topsoil C content and C:N ratio in the 0–20-cm layer but increased the subsoil C and N content at the 30–70-cm depth. Soil C content scaled approximately isometrically (scaling exponent ≈ 1) with N content in all soil layers across all invasion stages.

These findings highlight the general patterns of bamboo invasion-induced changes in soil stoichiometry and provide new insights into the events in forest ecosystems caused by bamboo invasion.