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In order to explain the difference of survival response of plants at different levels in evergreen broad-leaved forest to the Phyllostachys edulis expansion from the perspective of ecological stoichiometry homeostasis, this study used the method of space-time substitution, a typical P. edulis evergreen broad-leaved forest interface including P. edulis forest, P. edulis broad-leaved mixed forest and evergreen broad-leaved forest was selected in Jinggangshan National Nature Reserve, Jiangxi Province. The N and P contents of soil and leaves of P. edulis, broad-leaved trees, shrubs and herbaceous layer plants in each forest were compared and analyzed. The results were as follows: (1) From bamboo forest to evergreen broad-leaved forest, the soil N content and N∶P increased, while soil P content decreased; the leaf P contents of tree species (Machilus thunbergii, Alniphyllum fortunei and Daphniphyllum macropodum) decreased and the N∶P increased. Unlike the trees, the leaf N and P stoichiometric characteristics of plants both in shrub and herbaceous layers showed no significant change, except the shrub tree Lindera erythrocarpa. (2) The soil N∶P was positively correlated with the leaf N∶P of trees, negatively correlated with that of shrubs and had no correlation with that of herbaceous plants, respectively. (3) The leaf N and P contents and N∶P for P. edulis remained stable. In conclusion, P. edulis expansion changes plant leaf N and P stoichiometric characteristics by altering the soil N and P stoichiometric characteristics. Shrubs and herbaceous plants are less affected, however, it causes the imbalance of plant N and P stoichiometric characteristics of tree layer plants, which may be an important reason for the survival of tree species in evergreen broad-leaved forest.

Generally, deciduous and evergreen trees coexist in subtropical forests, and both types of leaves are attacked by numerous insect herbivores. However, trees respond and defend themselves from herbivores in different ways, and these responses may vary between evergreen and deciduous species. We examined both the percentage of leaf area removed by herbivores as well as the percentage of leaves attacked by herbivores to evaluate leaf herbivore damage across 14 subtropical deciduous and evergreen tree species, and quantified plant defenses to varying intensities of herbivory. We found that there was no significant difference in mean percentage of leaf area removed between deciduous and evergreen species, yet a higher mean percentage of deciduous leaves were damaged compared to evergreen leaves (73.7% versus 60.2%). Although percent leaf area removed was mainly influenced by hemicellulose concentrations, there was some evidence that the ratio of non-structural carbohydrates:lignin and the concentration of tannins contribute to herbivory. We also highlight that leaf defenses to varying intensities of herbivory varied greatly among subtropical plant species and there was a stronger response for deciduous trees to leaf herbivore (e.g., increased nitrogen or lignin) attack than that of evergreen trees. This work elucidates how leaves respond to varying intensities of herbivory, and explores some of the underlying relationships between leaf traits and herbivore attack in subtropical forests.