Badlands and the dynamics of human history, land use, and vegetation through centuries

In temperate climates, vegetation dynamics can dominate the fate of the badlands. In fact, in absence of disturbances such a grazing and burning, plant encroachment can condemn badlands to disappear. Thus, this type of badlands is either formed and developed under more arid conditions, or is due to some sort of mismanagement and misuse. This study provides an update on the denudation rate on this type of badlands (for a biancana badland in Central Italy, close to the ancient town of Siena). The result show a denudation rate of 2 cm a-1. Hence, the biancana site resulted to have been formed starting from the XIV century. The climatic conditions were similar to the present one, even if cooler and wetter. Hence, plants could have easily colonized the erosion scars indicating that factors controlling the badland origin should be searched elsewhere. Anthropic action was explored with a deep insight into the medieval period. We found that (i) the plague depopulation (which kept peasant population very low for more than 50 years), (ii) the change of the social structure in charge of the countryside management, and (iii) the need for the Siena republic to attract peasants, concurred to the creations of favorable circumstances for the badlands formation from previous pastures and croplands. Similar factors can hold for many badlands, following local history.