José Arnáez

Soil erosion and sediment redistribution in vineyards often exceed tolerable thresholds, but comparative field measurements across regions remain limited because studies use different methods and sampling designs. This study assesses soil redistribution in vineyards using a common field-based approach. Thirteen vineyard sites across Spain, covering contrasting climates, parent materials, soil types, management conditions, and vineyard ages (2–40 years), were surveyed using the Improved Stock Unearthing Method (ISUM). Soil surface changes were measured along systematic transects and combined with site-specific bulk density and vineyard age to estimate soil mobilization rates in t ha⁻¹ yr⁻¹. Measured surface changes ranged from −28 to +19 cm, while soil mobilization rates varied considerably among sites. The highest net soil losses were recorded in a young vineyard developed on limestone (−103.3 t ha⁻¹ yr⁻¹) and in a vineyard on marls (−87.7 t ha⁻¹ yr⁻¹). Other sites showed moderate net erosion (−3.9 to −15.4 t ha⁻¹ yr⁻¹), whereas positive balances (+7.2 to +17.9 t ha⁻¹ yr⁻¹) were observed in some older or more stable vineyards. Differences among sites suggest that vineyard age and parent material are relevant factors when interpreting erosion magnitude, while management conditions may contribute to the spatial variability of soil redistribution. Spatial maps based directly on ISUM measurements showed marked differences between erosion and deposition areas within individual vineyards, without the use of spatial interpolation. Applying the same ISUM protocol across contrasting vineyard conditions allowed soil redistribution patterns to be compared using a consistent field procedure. The results also showed the large variability that can occur among vineyard systems.

The Mediterranean region is facing severe hydrological challenges. Rising temperatures, remarkable fluctuations in precipitation, more frequent and intense droughts, and widespread revegetation in the headwaters due to farmland abandonment explain the observed decreases in river discharge across the region. Particularly, farmland abandonment in mountain areas favors woody encroachment, increasing water consumption by vegetation and rainfall interception. In contrast to the reduction of surface water resources, lowland areas are experiencing a growing water demand, primarily driven by increasing consumption in irrigated agriculture (which accounts for over 80% of total water use), tourism resorts, and urban and industrial areas. This contradictory trend between water resources generation and water demand is responsible for increasingly marked tensions, driving many regions toward environmental and social collapse. This includes inland and coastal wetlands (such as deltas and marshes), which are now under threat of extinction or face severe conflicts between wildlife, vegetation, and agricultural demands. In this review, we examine the conflicts between runoff generation in the highlands and water consumption in the lowlands of the Mediterranean region in order to improve land and water management and to ensure the survival of key ecosystems. The development of socio-hydrological scenarios and adaptive governance strategies will be critical for anticipating future conflicts and designing sustainable pathways for the management of scarce water resources.