A method to assess the fragility of a terraced system as an example of landscape agronomic analysis
Résumé
In this chapter, we develop a spatially explicit method to assess the fragility of a terraced system. The fragility concept combines into a single term analysis of degradation risk or vulnerability and the localised need for and prioritisation of land-management actions. We applied it to a terraced system as an example of agricultural landscapes characterised by intense anthropic reshaping that require continuous management to preserve functional stability. The aim was to zone the terraced system according to its fragility, assessed as the distance of terrace elements and their network from expected functional performances. The method was a GIS-based multi-attribute decision analysis, which was applied to Monte Pisano (Tuscany, Italy), illustrative of Mediterranean terraced systems. The decision-making problem was to identify priority zones for management (i.e. the most fragile) to ensure functional stability of the overall system. It was addressed in five steps: selecting and processing a set of attributes, combing them to define homogeneous management zones, then classifying and testing the reliability of the results using metrics based on a confusion matrix. Each step was co-conceived with the active participation of local decision-makers to enhance their understanding of the terraced system and ensure that they understood the analytical process.