A multicriteria protocol for the set-up and long-term monitoring of a pilot project for the restoration of alpine vegetation threatened by climate change

Climate change triggers changes of vegetation floristic composition, physiognomy and even the onset of new successional pathways, requiring adequate, robust and replicable methodological approaches to properly track these changes. In tundra ecosystems woody plants are encroaching into grasslands and snowbeds, inducing their gradual regression. “Back from the Future” is a pilot project performing selective shrub removal from grasslands and snowbeds in the Italian Central Alps to contrast climate-driven shrub encroachment and promote the recovery and active conservation of vegetation communities. Here we propose a multi-criteria research protocol providing a quantitative tool for: a) the set-up of the manipulation experiment; b) the assessment of the full comparability of manipulation and control areas; c) the long-term monitoring of the efficiency of the manipulation experiment. The experiment was carried out in three study sites (Braulio, Cedec, Sforzellina) across an elevation gradient from the subalpine to the nival belts in the Italian Central Alps. At each study site we identified a control and a manipulation zone to assess the efficiency of the manipulation experiment compared to the natural ecosystem dynamics. The multi-criteria research protocol integrates different sampling approaches: mapping and morphological characterization of trees and shrubs; phytosociological survey of permanent plots; grid-point intercept survey of permanent plots; line-intercept survey along transects; allometric shrub measurements along transects. Our data show that this protocol is applicable to different vegetation types, across different elevation belts, and is suitable to match different targets and/or bioindicators of change. Indeed, the limitations of each selected method when individually applied can be overcome by their combination. Our data demonstrate the full comparability of the control and manipulation zone at each of the three study sites in terms of species richness, floristic composition, species coverage, shrub characteristics and volume. Our results supported the feasibility of this protocol as tool for the set-up of the experiment, to assess the full comparability of control and manipulation zones, and perform a detailed monitoring of the effects and the feasibility of the restoration action and the success and efficiency of this pilot project. The protocol elaborated in the frame of this pilot project could be exported beyond the local context and applied to similar mountain regions, especially in the European Alps, for the planning, set up and monitoring of good land management practices aiming to climate change mitigation.