Terracing: From Agriculture to Multiple Ecosystem Services

Agricultural terraces are widely spread all over the world and are among the most evident landscape signatures of the human fingerprint, in many cases dating back to several centuries. Agricultural terraces create complex anthropogenic landscapes traditionally built to obtain land for cultivation in steep terrains, typically prone to runoff production and soil erosion, and thus hardly suitable for rain-fed farming practices. In addition to acquiring new land for cultivation, terracing can provide a wide array of ecosystem services, including runoff reduction, water conservation, erosion control, soil conservation and increase of soil quality, carbon sequestration, enhancement of biodiversity, enhancement of soil fertility and land productivity, increase of crop yield and food security, development of aesthetic landscapes and recreational options. Moreover, some terraced areas in the world can be considered as a cultural and historical heritage that increases the asset of the local landscape. Terraced slopes may be prone to failure and degradation issues, such as localized erosion, wall or riser collapse, piping, and landsliding, mainly related to runoff concentration processes. Degradation phenomena, which are exacerbated by progressive land abandonment, reduce the efficiency of benefits provided by terraces. Therefore, understanding the physical processes occurring in terraced slopes is essential to find the most effective maintenance criteria necessary to accurately and adequately preserve agricultural terraces worldwide.