Degradation of litter quality and decline of soil nitrogen mineralization after moso bamboo (Phyllostachys pubscens) expansion to neighboring broadleaved forest in subtropical China

Aims Moso bamboo (Phyllostachys pubescens) is a typical native invasive plant imposing serious threats on ecosystem processes and functions. A primary concern is alterations of litter and soil N mineralization in evergreen broadleaved forests coupled with bamboo population expansion. Methods We conducted a field study to determine the litter production, quality, N resorption efficiency, and soil N mineralization rates in bamboo-dominated forest (BDF) and adjacent uninvaded evergreen broadleaved forest (EBF) in subtropical China. Results The mean annual litter production for BDF was 5.82 Mg ha(-1), 36.0 % lower than that for EBF (9.09 Mg ha(-1)). Litter N concentration was also lower, but C: N was higher after bamboo expansion, coupled with higher N resorption efficiency for Moso bamboo and lower litterfall, resulting in potential N return decreasing as much as 60.41 kg N ha(-1) yr(-1-1) to the soil. The soil N net nitrification and mineralization rates exhibited lower values in BDF than in EBF. In addition, annual soil N mineralization rate was positively correlated with litter production but negatively with C: N ratio of litter. Conclusions Expansion of bamboo into neighboring EBF decreased litter production and quality, reduced soil N mineralization rate, and ultimately retarded N cycling. These effects should be carefully considered in the design of restoration strategies for ecosystems impacted by bamboo species.