Assessing the impact of vegetation cover changes and post-fire effects through an enhanced sediment flow connectivity index (SfCI)

Abstract

Land cover plays a fundamental role in surface dynamics that involve sediment connectivity. Land cover types can physically mitigate, prevent or increase sediment production and mobility on the surface. Further, changes in land cover, particularly in vegetation classes, can directly affect these processes, especially if they occur over short time periods or even more rapidly after extreme events such as fires. This study analyses vegetation cover changes in the Lama Camaggi catchment (southern Italy) in relation to its sediment connectivity pattern, described by Sediment flow Connectivity Index (SfCI). The Normalized difference vegetation index (NDVI), derived from satellite data, is utilized to detect vegetation cover changes over 8-year interval and following fire events. The main objective is to evaluate how the NDVI improves the flexibility of SfCI in defining surface dynamics on both spatial and temporal scales. The findings indicate that (1) NDVI changes identify vegetation cover changes in a short period in many areas of the catchment, potentially affecting sediment connectivity, and (2) the implementation of NDVI in the SfCI helps detect post-fire effects on sediment mobility and connectivity. Integrating NDVI enhances the SfCI algorithm providing a more dynamic description of sediment patterns.