Londoño (2008) highlighted the effect of abandonment on the Inca agricultural terraces since ∼1532 A.D., represented by the development of rills and channels on terraces where the vegetation is absent. Lesschen et al. (2008) underlined the fact that that terracing, although intended as a conservation practice, enhances erosion (gully erosion through the terrace walls), especially after abandonment. These authors carried out a study in the Carcavo basin, a semi-arid area in southeastern Spain. More

than half of the abandoned fields in the catchment area are subject to moderate and severe erosion. According to these studies, the land abandonment, the steeper terrace slope, the loam texture of the soils, the valley bottom position, and the presence of shrubs on the terrace walls are all factors that increase the risk of terrace failure. Construction of new terraces should therefore be carefully planned AZD5363 research buy and be built according to sustainable design criteria (Lesschen et al., 2008). Lesschen et al. (2008) provided guidelines to avoid the land erosion due to abandonment. They suggested the maintenance of terrace walls in combination with an increase in vegetation cover on the terrace, and the re-vegetation of indigenous grass species on zones with concentrated flow to prevent gully erosion. Lesschen et al. (2009) simulated the runoff

and sediment yield of a landscape scenario without agricultural terraces. They found values higher by Cell press factors of four and nine, respectively, when compared to areas with terraces. Meerkerk et al. (2009) examined find more the effect of terrace removal and failure on hydrological connectivity and peak discharge in a study area of 475 ha in southeastern Spain. They considered three scenarios: 1956 (with terraces), 2006 (with abandoned terraces), and S2 (without terraces). The analysis

was carried out with a storm return interval of 8.2 years. The results show that the decrease in intact terraces is related to a significant increase in connectivity and discharge. Conversely, catchments with terraces have a lower connectivity, contributing area of concentrated flow, and peak discharge. Bellin et al. (2009) presented a case study from southeastern Spain on the abandonment of soil and water conservation structures in Mediterranean ecosystems. Extensive and increasing mechanization of rainfed agriculture in marginal areas has led to a change in cropping systems. They observed that step terraces have decreased significantly during the last 40 years. Many terraces have not been maintained, and flow traces indicate that they no longer retain water. Furthermore, the distance between the step terraces has increased over time, making them vulnerable to erosion. Petanidou et al. (2008) presented a case study of the abandonment of cultivation terraces on Nisyros Island (Greece).