Erosion monitoring with terrestrial laser scanning in representative biancane badlands of Central and Southern Italy

This study aims to assess erosion dynamics in two Italian biancane badland sites, by means of  Terrestrial Laser Scanner (TLS), with high spatial resolution multitemporal surveys. The study sites are located in Tuscany and in Basilicata regions and are representative of the Mediterranean badland landscape. The former is a biancana subhumid badland hillslope of the Upper Orcia Valley, while the latter is a semiarid biancana landscape located in the tectonically active area of Aliano. The multitemporal survey and the morphometric analysis of the derived high resolution digital elevation models allowed to quantify the short- to medium-term erosion rates (5-10 years) affecting these landforms and to identify the main denudation processes responsible of the morphoevolution.

The results showed a very high erosion rate at both biancane sites, where it reaches, on average, 1.4 cm y^-1 in Basilicata and 2.7 cm y^-1 in Tuscany. The differences could be attributed to the dissimilar climatic conditions of the two sites:  Radicofani is affected by higher annual average rainfall, mainly due to a second peak (in addition to the autumn one) that occurs in spring, that is also reflected in enhanced mass movement events that model the subhumid biancane together with water erosion;  Aliano site is characterized by lower annual rainfall, mainly concentrated in late autumn-early winter, followed by long dry periods that also affect the erosion processes.

TLS is the ideal method to quantify denudation and erosion dynamics in biancane badlands since it allows very precise and detailed morphology detection. Furthermore the obstacles due to time-consuming and labor-intensive surveys, together with the shadowing effects, can be easily overcome because biancane generally origin in gentle dipping slopes, thus effortlessly accessible areas, where vegetation is often sparse as a result of ancient anthropic deforestation practices or climatic conditions in more arid badlands.