Positive Effects of Reforestation on the Diversity and Abundance of Soil Fauna in a Landscape Degraded Red Soil Area in Subtropical China

Serious soil degradation due to human intervention in subtropical China has resulted in a series of ecological problems. Soil fauna is an important part of forest soil ecosystems and plays a vital role in the maintenance of soil quality and can sensitively reflect the soil disturbances caused by human activities. This study assessed the long-term effects of reforestation on the soil fauna community and underground food web. Soil fauna was sampled from plots in a 30-year reforestation positioning test site. Six reforestation models (the pure Schima superba (Ss) forest, pure Liquidambar formosana (Lf) forest, pure Pinus massoniana (Pm) forest, mixed forest of Lf & Ss, mixed forest of Pm & Ss, and the mixed forest of Lf & Pm) were chosen in Taihe County, southern China. The results found that the mixed vegetation restoration of Lf & Pm significantly improved the soil fauna abundance and biomass when compared with other reforestation models in the degraded red soil region. Acari and Collembola accounted for 65.8% and 23.3%, respectively, of the total soil fauna abundance in the region. The mixed forest of Lf & Pm had a positive effect on the abundance of secondary decomposers and micro predators in Acari. Moreover, a significant increase in the abundance of Collembola was found in the Lf & Pm stand type. The stand type with the highest soil faunal population also had a higher soil fauna biomass. Therefore, reforestation in a degraded red soil area had positive effects on the soil fauna community.