Rainfall interception and plant community in young forest restorations

The conversion of tropical forests to human land-use threatens biodiversity conservation and the delivery of many ecosystem services, especially water-related ecosystem services. In these landscapes, many investments have been made to restore native forests and recover hydrological processes lost by deforestation. Rainfall interception is a key hydrological process for water-related ecosystem services' maintenance, which plays an important role in runoff, infiltration, erosion control, and flood regulation. We evaluated rainfall interception over a 1-year period in eight restoration sites within the Brazilian Atlantic Forest. We used the interception function as an indicator of water dynamics recovery in actively restored forests. Monthly rainfall interception was measured by 80 interceptometers distributed within the sites (10/site), and 24 pluviometers were installed in open fields (3/site) close to the restoration sites to collect total precipitation (P) incidents over the sites. We also measured plant community attributes involved in the interception process (density, basal area, tree species richness, and the ratio of deciduous plants). The average rainfall interception reached 21.4 +/- 3.9%, but a significant variability was observed among sites. Results showed that 65% of the monthly interception collected is below 30 mm.month(-1). Basal area and species richness were forest attributes positively correlated to each other and the most important in the interception process. The results show that actively restored forests can reestablish rainfall interception rates similar to those of mature tropical forests in the short term (10 years). In addition, more time or complementary interventions are needed for plant communities to reach expected attributes' values. Self-organized maps analysis showed a negative relationship between interception and the proportion of deciduous plant individuals. We present information to support land-use policy decisions, as the results revealed insights regarding the effects on the water cycle that may result from increasing forest cover. We argue that restoring ecosystem services should be the main goal of restoration programs and determining if hydrological processes are being effectively recovered by restoration actions is crucial for achieving water sustainability.