Soil macrofauna and water-related functions in patches of regenerating Atlantic Forest in Brazil

The Atlantic Forest is the most threatened Brazilian biome, with less than 10% of its original surface cover remaining. Thus, several programs of payment for ecosystem services have been developed in this biome focusing on revegetation of degraded areas. Forest regeneration promotes the development of soil invertebrate communities that play an important role in soil processes, delivering a wide range of ecosystem services. We studied the changes in macrofauna communities in three forests under different regeneration stages and the relationship between these invertebrates and soil chemical and physical properties. Macrofauna and soil chemical and physical properties were sampled until 30 cm depth in three forest fragments of the Brazilian Atlantic Forest under different regeneration stages: young regenerating forest (similar to 8 years old), secondary forest in intermediate regeneration stage (similar to 20 years old) and native secondary forest fragment. No significant differences in saturated hydraulic conductivity (K-s) were observed among sites, however, the old native forest showed reduction in Ks in deeper layers compared to young regenerating forests. Several macrofauna taxa were positively correlated with Ks and soil carbon. The stage of regeneration modified the abundance and diversity of these invertebrates in general (except for earthworms), and the old native forest showed high abundance of most taxa. In conclusion, our study highlights the potential of macrofauna communities as robust indicators of soil functions re-establishment in regenerating forests within the Atlantic Forest biome. The observed positive correlations between macrofauna abundance and diversity with soil water infiltration and organic carbon content emphasize the key role of these invertebrates to essential ecosystem functions.