Increasing phosphorus limitation along three successional forests in southern China

Background and Aims Phosphorus (P) is commonly one of most limiting nutrients in tropical and subtropical forests, but whether P limitation would be exacerbated during forest succession remains unclear. Methods Soil phosphatase activity is often used as an indicator of P limitation. Here we examined soil acid phosphatase activity (APA) underneath tree species in pine forest (PF), mixed pine and broadleaf forest (MF) and monsoon evergreen broadleaf forest (MEBF) which represented the early, middle and late successional stages of subtropical forests in China, respectively. We also analyzed other indicators of P status (soil available P and N and P stoichiometry of the tree species). Results APA or APA per unit soil organic carbon under tree species was relatively low in the early successional forest. Different from PF and MF, soil available P beneath the tree species was lower than in the bulk soils in MEBF. Soil APA was closely related to N:P ratios of tree species across all three forests. Conclusions Our results imply that P limitation increases during forest succession at our site. The dominant tree species with low soil APAs in MEBF are likely more P-limited than other tree species.