Agricultural terraces as a proxy to landscape history on Madeira island, Portugal

Since the early fifteenth century, huge parts of the Portuguese island of Madeira have been transformed from a natural into a cultural landscape. The most eminent feature of this anthropogenic landscape change is agricultural terraces, which are extremely solid in structure and thus resilient to erosion and collapse. This makes them ideal proxies for studying landscape dynamics. The analysis of eight soil profiles delivered answers to questions regarding (1) the age of terraces at different altitudes, (2) the stability of the soil, (3) the organic matter content of the soil, (4) the traditional practices for maintaining soil fertility and (5) the characteristics of local terrace architecture. The analysis proves an excellent adaptation of the terrace structures to local topography. The supporting walls are made of materials ranging from hewn basalt stones to soil blocks. Soil quality, regarding organic matter and structure, has been maintained by the applied traditional practices.