After the catastrophic Wenchuan earthquake in 2008, mountainous ecosystems in the Longmen Mountains were seriously destructed. This study aimed to investigate the relationships among rainfall, slope gradients, vegetation cover, and runoff as well as soil loss, through comparing forests and earthquake-induced landslides.

Micro-catchments were established on north-facing slopes with PVC material plots (50 cm 50 cm) from August to September 2010. The grading comparison method was adopted to compare soil erosion of different intensities. The result demonstrated significant difference between the amount of accumulated runoff of landslide sites and forests sites. There was less runoff and soil loss at forests sites than landslide sites due to complicated community structures and rainfall interception of forests.

There was more serious soil erosion at landslides sites with runoff increase per unit. Classification and gradation of soil erosion intensity indicated that the proportion of total soil loss exceeding S (severe) grade was the highest at landslides sites, while more than 80% soil erosion belonged to VL (very low) at forests sites. Even at VL grade, landslide sites produced 202.35 ton per km2, nearly 400 times more than that at forest sites of 0.52 ton per km2. There was more than 4.72 106 t soil loss produced from earthquake-induced landslides even two years later.

It is now still a great challenge for ecological restoration and rehabilitation of earthquake damaged areas due to the spatial and temporal difference of heavy rainfall, which always leads to serious landslides on a large scale.

Prof.WU Ning's team from Chengdu Institute of Biology, Chinese Academy of Sciences conducted this research.