Fern cover and the importance of plant traits in reducing erosion on steep soil slopes

•Erosion-reducing potential of ferns on steep slope conditions was assessed.•Fern cover and plant traits had significant effects on erosion control.•80% fern cover could significantly reduce runoff and sediment loss.•Capabilities of ferns in erosion control were correlated with several plant traits.

Soil slopes constructed in southern China are susceptible to serious erosion due to substrate characteristics and high precipitation, which is commonly mitigated by revegetation. Ferns are potentially useful for erosion control due to their dense plant cover and adaptation to slopes. However, information regarding the effectiveness of ferns in erosion control is scarce. This study assessed the erosion-reducing potential of recently planted ferns on slopes. Five native fern species of southern China, namely, Blechnum orientale, Cyclosorus parasiticus, Dicranopteris pedata, Nephrolepis auriculata and Pteris vittata, were chosen for the assessment. Each fern species was grown to reach two levels of cover (40% and 80%) in 1.0 × 0.5 m2 soil boxes tilted to 50°, and boxes with bare soil acted as the control. The erosion control performance was tested using a rainfall simulator, which provided a rainfall intensity of 100 mm h− 1 to reflect a heavy rainstorm event. Various plant traits were examined to explore their roles in reducing erosion. The results demonstrated that both cover and plant traits have significant effects on the erosion-reducing potential of ferns. The high cover of ferns (80%) could reduce the runoff volume by 65.0% and sediment loss by 96.1% compared with the control. The leaf area index (LAI), root area ratio (RAR) and root density (RD) were highly correlated with erosion-reducing potential. Among species, N. auriculata outperformed the other species by having stronger performance of these plant traits. To confirm the results further, more field experimentation and comparisons of ferns and grasses in mitigating runoff and sediment loss on soil slopes are necessary to evaluate the effectiveness of ferns in erosion control under in situ conditions.