Secondary succession on landslides in submontane forests of central Taiwan: Environmental drivers and restoration strategies

Aims We aim (a) to investigate and describe the species composition of vegetation that has recolonized landslides and describe its relationship to environmental variables; and (b) to propose a set of plant species and restoration strategies applicable for speeding up the restoration process. Location Elevation between 240 and 1,350 m a.s.l. in central Taiwan, East Asia. Methods We delimited the boundaries of landslides using aerial photographs taken between 1975 and 2015. We sampled 52 plots from 48 selected landslides and measured 21 environmental variables to identify the significant factors related to species composition. Cluster analysis and transformation‐based redundancy analysis were used to determine the vegetation groups and corresponding environmental variables; the environmental differences between different vegetation types were evaluated by ANOVA. Results We classified the vegetation into four types and related each of them to a successional age, landslide position and soil pH, as well as Mn and Mg contents. Two early‐successional types (aged 5–10 years) mainly occurred in habitats in steep slip zones, which are dominated by pioneer woody species and have a high coverage of grasses, forbs, or ferns thickets. In contrast, the mid‐successional vegetation type (aged 16–40 years), growing on flat habitats, consists of pioneer woody species in the canopy layer and seedlings or saplings of shade‐tolerant species in the understorey. Conclusions We confirmed that the composition and recruitment of species can be well explained by environmental differences between landslide zones and successional age. Some framework species and some shade‐tolerant woody species can be applied to landslide scars with plant dispersal limitation problems and habitats suffering from poor local species pools, respectively. To overcome the problem of vegetation succession blocked by Miscanthus and ferns thickets, we suggest that pioneer woody species and herb species can be seeded on landslide scars at once for erosion control. As the ongoing climate change increases the intensity of extreme precipitation events followed by serious landslides, restoration of landslide‐affected habitats becomes ever more important. In our study from central Taiwan, we document spontaneous vegetation succession on landslide habitats and describe typical plant communities of different successional stages. We also suggest detailed and practical strategies to speed up the restoration effort.