A critical view of the desertification debate in southeastern Spain

Abstract

In Spain, desertification has been-and is still-mainly associated with soil erosion, particularly in natural and semi-natural systems. Such association cannot be supported either from the scientific or the socio-economic point of view. Most average values of erosion rates in Spain have been overestimated, especially in the case of natural systems. High rates of soil erosion in natural systems are usually restricted to spatially limited areas like badlands, most of them generated through active natural geomorphologic processes. The main erosion problems are not found in natural environments but in agricultural systems, especially in marginal agricultural areas on steep slopes and with bad agricultural practices and also in intensively irrigated lands, especially greenhouses. The association of arid zones with the ancient destruction of vegetation is rooted in simplistic ideas considering areas with scarce vegetation, little biomass or limited height to be generated by negative human interventions. However, in arid and semiarid systems this is not always true. The simplistic ideas linking scarce vegetation with desertification is also deeply negative for the conservation of the outstanding biodiversity of arid systems, most of them included in the European Habitat Directive. The main desertification problem in Spain is generated by unsustainable water management. The current expansion of irrigated lands outside the areas suited for agriculture is increasing the intensity of aquifer exploitation, already causing serious problems of salinization, the loss of springs and wetlands and associated biodiversity and the exhaustion of non-renewable groundwater resources.

Climate‐driven decrease in erosion in extant Mediterranean badlands

“…Scenarios of anthropogenically-forced climate change for the Mediterranean appear to refl ect the impacts of a northward movement of subtropical high pressure in summer and a predominantly positive NAOi in winter. Under these conditions more of the Mediterranean badlands are likely to become increasingly stable, thus potentially severing the remaining contested links between erosion and desertifi cation (Martínez-Fernández and Esteve, 2005).…”

Farming practices and policy measures for agricultural soil conservation in semi‐arid Mediterranean areas: The case of the Guadalentín basin in southeast Spain

“…(2) The widespread conversion of land into irrigated agriculture over the last 40 years has resulted in a severe transformation of the landscape, including a heavy alteration of topography and even the elimination of the soil layer. Most of the greenhouse agriculture in the area is based on heavy terracing on moderate slopes and/ or eliminating soils and planting directly on bedrock (Barberá et al, 1997;Martínez-Fernández and Esteve, 2005). (3) In the last decade, there has been an expansive process of urbanisation for residential tourism that competes with agriculture for soil and water resources.…”

“…This risk increases in a semi-arid climate, where there is a severe water deficit. The main soil degradation phenomena in southeast Spain are located in cultivated areas, especially marginal and steep rainfed agricultural areas where almond, vineyards and olive are cultivated (Martínez-Fernández and Esteve, 2005). However, these problems are not exclusive to rainfed agriculture.…”

Territorial transformation and water utilization: hydrological planning scenarios in the Segura river basin

“…The main territorial characteristic of the peninsular region of Southeast Spain, where the Segura river basin is situated, is aridness [3,4], with important problems of erosion and desertification [5], associated in turn with an inadequate and unsustainable treatment of water and soil in the agricultural terrains [6]. The benign climate, with high solar radiation and luminosity, together with the good agronomic quality of the soil, have made this zone a traditionally very productive one, affording high economic yields in agricultural [1].…”

“…Likewise, in this territory a sustainable water management has been considered as the principal means of fighting desertification, through the reduction of water demands, the control of expansion of irrigated areas, the sustainable management of the aquifers, etc. [6].…”