The Terraces of the Anti-Atlas: From Abandonment to the Risk of Degradation of a Landscape Heritage

Abstract

The Anti-Atlas is subject to an intense rural exodus. The agricultural terraces built for several centuries have been abandoned. They are gradually deteriorating. The risks of runoff and erosion are becoming significant. The objective was to study the effect of the abandonment of terraces on the risks of runoff and erosion in the territory of two villages, Tizerkine and Timzemzit. After the characterization of the soil surface conditions, the extent of erosion and the risk of runoff were qualified according to the age of abandonment. Erosion was assessed by estimating the “soil surface factor” (PAP/CAR method) and infiltration by the double ring method. The abandonment of the terraces has led to a reduction in the plant cover of the soil surface and its opening and to enhancing its compaction. The risk of runoff is high. A year of abandonment reduced the infiltration from 301.8 mm/h (SD: 105.8 mm/h) to 129.6 mm/h (SD: 28.9 mm/h). Furthermore, 5 years of abandonment reduced it to 62.9 mm/h (SD: 14.9 mm/h). The walls of the terraces are gradually being destroyed with an increasing age of abandonment. More than half (57%) of the terraced slope surface has suffered moderate to high water erosion. More than 11% of the surfaces are severely degraded after 20 years of abandonment. The heritage made up of these managed slopes is being lost. Particular attention must be paid to these landscapes in order to better rehabilitate and develop them.

Role of Agricultural Terraces in Flood and Soil Erosion Risks Control in the High Atlas Mountains of Morocco

“…Our findings highlighted dense forests, followed by cultivated terraces as being the most effective in promoting infiltration while reducing runoff, flood risks and sediment loss. This is in agreement with several studies including those by Cammeraat et al [32], Araya et al [33] and Sabir [25]. By fulfilling their soil and water conservation role, as highlighted in this study, cultivated terraces in the Ourika watershed can improve the livelihoods of the population.…”

“…This, together with land abandonment, could lead to increased risk of soil degradation [22,23], especially since Mediterranean soils are already considered as a fragile part of the regions' ecosystem [24]. Indeed, a reduction in vegetation cover and increased soil compaction have been observed, linked to the abandonment of terraces in the Anti-Atlas region, with reduction of infiltration up to 301.8 mm/h along with an increase of risk of runoff [25].…”

Terraced Landscapes and Hydrological-Geological Hazards: Innovative Approaches and Future Perspectives

“…The paper by Sabir [20] closes the Special Issue, showing how the effects of land abandonment in the terraces of Anti-Atlas (described by Boselli in [17]) lead to a reduction of infiltration in unmanaged terraced landscapes, even after few years. The author suggested immediate action to rehabilitate and restore the socio-ecological systems of terraced areas, to avoid consequent hydrological and hydrogeological hazards.…”

“…Such kinds of research efforts could be considered of particular interest, since, while most of the "historical" terraced landscapes were created a long time ago, they offer the possibility of analyzing the different parts of the terracing implementation, highlighting possible errors, their consequences, but also innovative design methodologies. Some of the case studies focused on issues related to terrace abandonment (Figure 3) [13,15,17,19,20], which represent an issue at the global scale [1,6,7], while others focused instead on new terrace system implementation [14,16]. Such kinds of research efforts could be considered of particular interest, since, while most of the "historical" terraced landscapes were created a long time ago, they offer the possibility of analyzing the different parts of the terracing implementation, highlighting possible errors, their consequences, but also innovative design methodologies.…”

“…Some of the papers presented in the Special Issue also highlighted the importance of advanced hydrological analyses at the terraced landscape scale [14,18,20]. Such approaches are not frontier research, but the papers submitted considered different and heterogeneous case studies (Moroccan Anti-Atlas, Ethiopian and Philippine rice terraces), which were understudied under this point of view, and which therefore could be further explored.…”