Soil and Water Bioengineering shallow landslide restoration project enhances biodiversity conditions: a study case in Tuscany (Italy)

The long-term biodiversity effects of ecological restoration projects are essential to understanding the dynamics of environmental processes induced by different applied techniques. Nature-based solutions (NBS) are defined as actions that use nature to protect, sustainably manage and restore natural or altered environments, providing benefits for both ecosystems and human well-being. Among NBS, Soil and Water Bioengineering (SWBE) techniques combine plants with timber and stone structures to restore riverbanks, combat soil erosion, and stabilise landslide areas, merging technical functionality with environmental restoration.

This study, conducted within the NBFC research centre, employs a multidisciplinary approach to monitoring biodiversity complexity (plants, soil microorganisms and insects) in ecological restoration projects using SWBE techniques. The research aims to quantify the multi-taxonomic diversity in a shallow landslide restored with SWBE methods in the Apuan Alps, Tuscany (Italy), and analyse the effects of ecological succession on biodiversity complexity.

The study area includes three shallow landslides triggered during an extreme weather event in 1996. During the 2024 vegetative season, field surveys were conducted in (1) a SWBE-restored landslide, (2) a naturally evolved landslide, and (3) a controlled landslide with minimal anthropic disturbance. All sites share comparable characteristics (e.g., slope, exposure, surrounding vegetation, and soil type).

Results show that slope stability in the SWBE restored landslide enables better development of tree vegetation, with a more structured canopy compared to the other two sites. Herbaceous species biodiversity indices indicate significant differences among sites, with the restored landslide achieving the highest alpha diversity, as evidenced by alpha-diversity index values. For soil microorganisms and insects, data elaborations show us differences in community composition according to beta-diversity analyses (Bray-Curtis parameters).

These findings underscore the importance of SWBE techniques in enhancing biodiversity and restoring ecological stability in degraded landscapes. An interdisciplinary approach is crucial to better understanding the long-term effects of nature-based solutions on slope stability and environmental restoration.