Acacia mangium increases the mesofauna density and diversity in the litter layer in Eucalyptus grandis plantations

摘要

The introduction of Acacia mangium in Eucalyptus grandis plantations improves the ecosystem services performed by microorganisms. However, the influence of these mixed plantations on epigeic mesofauna remains poorly understood. We hypothesized that the intercropping between E. grandis and A. mangium increases the epigeic mesofauna density and diversity. Our aim was to evaluate the mesofaunal density and diversity in the litter in order to establish correlations between mesofaunal, chemical attributes and seasonality in Acacia mangium (AC), Eucalyptus grandis (EU), and intercropping between E. grandis and A. mangium (M). We selected three plots of each system and collected five litter and five soil samples in two periods, October 2015 and March 2016, considered respectively as beginning of the rainy and of the dry season. In general, the mesofaunal orders correlated positively with AC, and negatively with EU. In March 2016, we sampled 12 times more invertebrates in litter than in October, possibly due to the differences in climatic conditions, since the litter moisture was higher in March than in October. We also found a higher C/N ratio and Mn content in the EU and a higher N content in AC. Thus, these chemical litter attributes seem to strongly affect the litter mesofauna community, since in March we found lower mesofaunal density and diversity in EU and higher mesofaunal density and diversity in AC. Therefore, we recommend the intercropping between E. grandis and A. mangium because it allows for the development of orders exclusive to AC plantations such as Symphyla, Protura and Pseudoscorpionida.