Plant-Best: A novel plant selection tool for slope protection

Abstract

Plant-Best is a novel tool for the selection of the most suitable plant cover against rainfall-induced shallow landslides. It explores the plant-derived likelihood of slope failure reduction under wetting and drying events, respectively. Plant-Best comprises five comprehensive open-source modules built in the freeware R. The modules’ objectives range from the spatial detection of landslide-prone zones to the integrated evaluation of plant-derived hydro-mechanical effects on sloped terrain; from the selection of the best performing plant species to the identification of sensitive plant traits. In this paper, we provide a detailed description of the Plant-Best modules and we show how this holistic tool can be effectively employed for plant cover selection in a shallow landslide context. To do so, we demonstrate the application of Plant-Best on a site with a history of slope failures in Northeast Scotland, where the tool is implemented using seven native plant species including both woody and herbaceous vegetation. The results reveal that different plant species were suitable for protection depending on the hydrological conditions – i.e. wetting or drying. Plant effects were limited to the topmost soil and, in general, underweight plants with dense root systems and broad thick canopies offered the best resistance to failure. This suggested that botanically diverse slopes with different plant functional groups are desirable for a more effective slope protection. Plant-Best proved to be a relatively simple but robust tool for the detection of landslide-prone zones, the selection and evaluation of plant covers, and the identification of relevant plant traits related to shallow landslides mitigation. The open-source nature of the tool confers a great versatility and applicability to the tool which can be deployed as a multi-disciplinary aid to the decision making process.