A proposal for assessing the success of soil bioengineering work by analysing vegetation : results of two case studies in the Italian Alps

The evaluation of the success of soil bioengi- neering work is an issue still poorly addressed by the sci- entific community. Nevertheless, soil bioengineering techniques are increasingly used worldwide when miti- gating the impact on the environment and the landscape is one, but not the only, goal of intervention. A tool to measure the success of soil bioengineering work, with reference to landslide stabilization, is presented in this paper: the index of ecological success (IES). The IES is based on the phytosociological analysis of vegetation and widens the potential applications of the ecological index of maturity (EIM), recently formulated by Giupponi et al. (Restor Ecol 23:635–644, 2015) to assess the degree of disturbance affecting a plant community. The IES com- pares the EIM values of the vegetation of an area affected by soil stabilization work with those of the expected veg- etation at a precise time after completion of soil stabi- lization work, providing values ranging between 0 (maximum failure) and 1 (complete success). The IES was applied in two study areas located on two mountain slopes of the Southern Alps (Italy) which, as a result of landslides, were subject to soil bioengineering work aimed at slope