Plant Selection Criterion for Nature-Based Landslide Risk Management

Nature-based landslide risk management (NBLRM) involves use of plants in mitigating slope instabilities. These interventions provide sustainable and cost-effective approaches for landslide disaster risk reduction. At present in Sri Lanka, attempts are made to incorporate beneficial services of plants species in implementing landslide risk mitigation measures. However, a guiding framework in selecting appropriate plant species for landslide prone sites had not been available. Effectiveness of plants for nature-based landslide risk management mainly depends on the root architecture and its mechanical properties. Ecological and socio-economic significance of plant species also play a major role in selection of plants, especially when the nature-based solutions are to be applied in disturbed landscape. After conducting a systematic literature review, four key factors were identified. Namely, Root strength characteristics, Hydrological significance, Ecological significance and Economic value. Performance of each species under respective factor was assigned a score, based on a scale of 4 depending on their suitability for stabilizing soil on slopes. A cumulative index greater than 2 and the compatibility with the eco-climatic region were considered when selecting plant species for landslide prone sites. The proposed plant selection criterion was used as a tool to rank 33 candidate plants collected from landslide prone areas in determining suitable species for NBLRM in Sri Lanka.