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22 páginas, 11 figuras, 3 tablas.-- El PDF del artículo es la versión manbscrita del autor. ; Farmland abandonment is a major problem in parts of Europe, particularly in mountain areas and semiarid environments. In such places, farmland abandonment represents a significant land use change from cropping to a complex of plant successions. The present study assesses the hydromorphological effects of land abandonment in Europe, and the consequences thereof with respect to water resource availability and soil erosion. The evolution of abandoned fields depends on (i) the time of abandonment; (ii) climatic conditions in the abandoned area; (iii) particular characteristics of the fields; (iv) the land management regimen following abandonment; and, (v) the role played by government policy. Throughout most of Europe, vegetation on abandoned farmland has evolved into dense forest or shrub. The expansion of vegetation explains, in part, the perceived decline in water resources, reductions in soil loss and sediment delivery, and the progressive improvement of soil characteristics. Such evolution has resulted in changing stream morphology, featuring narrowing and incision, and a decline in sedimentation level in Mediterranean reservoirs. The abandonment of bench terrace fields coincided with an increase in the occurrence of small landslides in the steps between terraces, as well as changes in the spatial organization of saturated areas. Plant colonization is slower in semiarid areas, increasing the development of soil crusts that reduce infiltration and increase overland flow. Land policies with detailed capability are necessary to remediate the consequences of farmland abandonment in various European environments. ; Support for this research was provided by the projects PROBASE (grant no. CGL2006-11619/HID; Consolider), financed by the Spanish Commission of Science and Technology; ACQWA (grant no. FP7-ENV-2007-1), financed by the European Commission; and PI032/08, financed by the Aragón Regional Government. The authors also acknowledge support from the Program of Research Groups of the Aragón Regional Government, and from RESEL (the Spanish Ministry of the Environment). N. Lana-Renault was the recipient of a research contract (under the I+D+I 2008–2011 National Program) funded by the Spanish Ministry of Sciences and Innovation. ; Peer reviewed

7 Pag., 6 Fig., 2 Tabl. ; Shifting agriculture has been practiced over large areas in middle-latitude mountains in the Mediterranean basin during periods of strong demographic pressure. On average, such land accounted for about 22.8% of the total cultivated area in the Central Spanish Pyrenees at the beginning of the 20th century. The use of experimental plots between 1992 and 2003 demonstrated that shifting agriculture increased overland flow, suspended sediment, and solute concentration. Total soil loss was about 14 times higher on plots under shifting agriculture than on plots under dense shrub cover, and almost 3 times higher than on permanent sloping fields. Erosion rates ranged between 0.1 and 1.4 t/ha/yr. The abandonment of shifting agriculture practices resulted in rapid plant recolonization and a decrease in runoff and soil erosion. Nevertheless, severe geomorphic processes were found to be still active several decades after abandonment, explaining landscape degradation and the occurrence of shallow landslides. ; Support for this research was provided by the following projects: PIRIHEROS (REN2003-08678/HID), CANOA (CGL2004-04919-C02-01) and EROFUEGO (REN2002-00133GLO), funded by CICYT, the Spanish Ministry of Science and Technology, and by RESEL (the Spanish Ministry of the Environment). Personal support for Santiago Beguería was provided by the Spanish Government Secretary for Education and Universities and the European Social Fund. ; Peer reviewed

Fernández-Fernández, José M. et. al.- 18 páginas.- Ilustraciones.- © 2017 Elsevier Ltd. All rights reserved. ; In this study, fossil debris-covered glaciers are investigated and dated in the Sierra de la Demanda, northern Spain. They are located in glacial valleys of approximately 1 km in length, where several moraines represent distinct phases of the deglaciation period. Several boulders in the moraines and fossil debris-covered glaciers were selected for analysis of Be-10 surface exposure dating. A minimum age of 17.8 +/- 2.2 ka was obtained for the outermost moraine in the San Lorenzo cirque, and was attributed to the global Last Glacial Maximum (LGM) or earlier glacial stages, based on deglaciation dates determined in other mountain areas of northern Spain. The youngest moraines were dated to approximately 16.7 +/- 1.4 ka, and hence correspond to the GS-2a stadial (Oldest Dryas). Given that the debris-covered glaciers fossilize intermediate moraines, it was deduced that they developed between the LGM and the Oldest Dryas, coinciding with a period of extensive deglaciation. During this deglaciation phase, the cirque headwalls likely discharged large quantities of boulders and blocks that covered the residual ice masses. The resulting debris-covered glaciers evolved slowly because the debris mantle preserved the ice core from rapid ablation, and consequently they remained active until the end of the Late Glacial or the beginning of the Holocene (for the San Lorenzo cirque) and the Holocene Thermal Maximum (for the Mencilla cirque). The north-facing part of the Mencilla cirque ensured longer preservation of the ice core. (C) 2017 Elsevier Ltd. All rights reserved. ; Support for this research was provided by the projects ESPAS (CGL2015-65569-R) (MINECO/FEDER), MOUNTAIN WARMING (CGL2015-65813-R) (Spanish Ministry of Economy and Competitiveness). The study was assisted by the High Mountain Physical Geography research group (Complutense University of Madrid) and the research group on Geomorphology and Global Change, which is supported by the Aragon Government and the European Social Fund. The 10Be measurements were performed at the ASTER AMS national facility (CEREGE, Aix en Provence, France), which is supported by the INSU, CNRS and the ANR through the "Projets thematiques d'excellence" program for the "Equipements d'excellence" ASTER-CEREGE action and IRD. Jose M. Fernandez-Fernandez received a grant from the FPU programme (FPU14/0650) (Spanish Ministry of Education, Culture and Sport). ; Peer reviewed

27 Pag., 2 Tabl., 5 Fig. The definitive version is available at: http://www.informaworld.com/smpp/title~content=t911751996 ; This paper analyses the evolution of high flows in the central Spanish Pyrenees during the period 1955-1995. The method applied makes it possible to assess whether the contribution of the largest daily discharge and rainfall events to the total annual runoff and precipitation remains stationary or shows any temporal trend. The results show a general negative trend in flood intensity in the last decades, together with an increase in the importance of low flows in the total annual contribution. However, a change in the frequency distribution of precipitation events has not been detected. The different behaviour shown by runoff and precipitation could only be explained as being due to the increase in vegetation cover that is a consequence of the farmland abandonment and reforestation that occurred during the 20th century. ; This study was supported by the following research projects: "Hydrologic and erosive processes in Pyrenean catchments, related to land use changes and climate variability" (PIRIHEROS, REN 2003-08678/HID) and "Characterisation and modelling of hydrological processes in gauged basins for the prediction of ungauged basins" (CANOA, CGL 2004-04919-c02-01), both funded by the CICYT, Spanish Ministry of Science and Technology. Personal support for S.B. was provided by the Spanish Government Secretary for Education and Universities and the European Social Fund. We thank the Ebro River Hydrographic Administration (Confederación Hidrográfica del Ebro) for providing the river discharge data. ; Peer reviewed

29 Pag., 1 Tabl., 11 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/0169555X ; This study investigated the characteristics, triggering factors, and spatial distribution of shallow landslides in relation to historical deforestation in the sub-alpine belt of the Pyrenees, particularly in the flysch sector. Shallow landslides in this area occur on straight and concave slopes, mainly covered by mesophyte grasslands, and contribute substantially to soil erosion and landscape deterioration. The investigated landslides were variable in shape and size, although common features included delimitation by a scar or semi-circular crown (averaging 32 m long × 10.15 m wide) and a tongue with a lobe at the foot of the scar area. The sliding surface coincided with the zone of contact of the C soil horizon with the bedrock, although in 13% of the cases the sliding surface occurred within the soil. The frontal lobes frequently trigger new landslides because of water accumulation and instability, resulting in a succession of interconnected landslides that can attain 100–200 m in length. Slope gradient appeared to be the most important factor correlated with shallow landslides. Thus, with slopes > 30° the soil was unstable and tended to slide even in dry conditions, whereas with slopes < 15° the soil was stable even under saturated conditions; shallow landslides were consequently concentrated on slopes between 15° and 30°. Rapid deforestation of the sub-alpine belt during the Middle and Modern Ages caused a sudden increase in hillslope instability. The studied landslides occurred only on deforested, grassland-covered hillslopes, and not in adjacent forested areas. Therefore, deforestation is considered to be a major factor contributing to shallow landslides, because of changes in soil hydrology and reduced soil strength as a consequence of decreased root cohesion, mainly coinciding with snowmelt and large rainstorms. ; Support for this research was provided by the projects PROBASE (CGL2006-11619/HID, Consolider), financed by the Spanish Commission of Science and Technology, ACQWA (FP7-ENV-2007-1), by the European Commission, and PI032/08 financed by the Aragón Regional Government. The authors also acknowledge support from the Program of Research Groups of the Aragón Regional Government, and from RESEL (The Spanish Ministry of Environment). ; Peer reviewed

The definitive version is available at: http://www.sciencedirect.com/science/article/pii/S0169555X13003073# ; [EN] Intense erosion processes are widespread in the Mediterranean region, and include sheet wash erosion, rilling, gullying, shallow landsliding, and the development of large and active badlands in both subhumid and semi-arid areas. This review analyses the main environmental and human features related to soil erosion processes, and the main factors that explain the extreme variability of factors influencing soil erosion, particularly recent land use changes. The importance of erosion in the Mediterranean is related to the long history of human activity in a region characterized by low levels of annual precipitation, the occurrence of intense rainstorms and long-lasting droughts, high evapotranspiration, the presence of steep slopes and the occurrence of recent tectonic activity, together with the recurrent use of fire, overgrazing and farming. These factors have resulted in a complex landscape in which intensification and abandonment, wealth and poverty can co-exist. The changing conditions of national and international markets and the evolution of population pressure are now the main drivers explaining land use changes, including farmland abandonment in mountain areas, the expansion of some subsidized crops to marginal lands, and the development of new terraces affected by landslides and intense soil erosion during extreme rainstorm events. The occurrence of human-related forest fires affecting thousands of hectares each year is a significant problem in both the northern and southern areas of the Mediterranean basin. Here, we highlight the rise of new scientific challenges in controlling the negative consequences of soil erosion in the Mediterranean region: 1) to reduce the effects and extent of forest fires, and restructure the spatial organization of abandoned landscapes; 2) to provide guidance for making the EU agricultural policy more adapted to the complexity and fragility of Mediterranean environments; 3) to develop field methods and models to improve the identification of runoff and sediment contributing areas; 4) to contribute to the conservation of landscapes (i.e. bench-terraced fields) having high cultural and productivity values; 5) to improve knowledge of the hydrological and geomorphological functioning of badlands, with the aim of reducing sediment yield and accessibility; 6) to better understand the effect of climate change on soil erosion in the Mediterranean region; and 7) to improve quantitative information on long-term soil erosion. ; Support for this research was provided by the projects INDICA (CGL2011- 27753-C02-01 and -02), HIDROCAES (CGL2011-27574-C02-01) and DISDROSPEC (CGL2011-24815), funded by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (ERDF-FEDER), ACQWA (FP7-ENV- 2007-1-212250), financed by the European Commission, and an agreement between the CSIC and the Spanish Ministry of Environment (RESEL). The Geomorphology and Global Change research group was financed by the Aragón Government and the European Social Fund (ESF-FSE). E. Nadal-Romero and N. Lana-Renault benefited from a research contract (Spanish Ministry of Economy and Competitiveness, Programme Juan de la Cierva). The authors acknowledge the comments from Prof. Mike Fullen and an anonymous referee, as well as the editorial labour from Prof. Takashi Oguchi. ; Peer reviewed

We are very grateful to all the referees for their indispensable and unselfish work that greatly contributed to the improvement of the quality of the papers. The Department of the Environment and the Department of Science, Technology and University of the Aragón Government, as well as the Innovation Ministry of the Spanish Government (CGL2011-12465), provided financial support to organise the scientific meeting "Geomorphological Research in Spain" (Zaragoza, September, 2011). We thank the International Association of Geomorphologists (IAG), the Spanish Society of Geomorphology (SEG), and the Spanish Society of Quaternary Studies (AEQUA) for supporting the initiative. We are also very grateful to Dr. Cinta Marín for helping with the preparation of the bibliometric data and supplementary material presented in this guest editorial. ; Peer Reviewed

Deglaciation processes in the upper Gállego Valley, central-southern Pyrenees, were studied using geomorphological mapping and 36 Cl cosmogenic dating of moraine and rock glacier boulders, as well as polished bedrock. Although the precise position of the Gállego Glacier during the global last glacial maximum is not known, there is evidence that ice tongues retreated to the headwaters, which caused subdivision of the main glacier into a number of individual glaciers prior to 17ka. A range of ages (16 to 11ka) was found among three tributary valleys within the general trend of deglaciation. The retreat rate to cirque was estimated to be relatively rapid (approximately 5km per ka). The mapped glacial sedimentology and geomorphology appears to support the occurrence of multiple minor advances and retreats, or periods of stasis during the late deglaciation. Geomorphological and geological differences among the tributary valleys, and error estimates associated with the results obtained, prevented unambiguous correlations of the advances with the late Pleistocene cold periods. During the latter advances, small glaciers and rock glaciers developed close to the cirque headwalls, and co-occurred under the same climatic conditions. No evidence for Holocene re-advance was found for any of the three tributary valleys. © 2015 University of Washington. ; This study was performed with the support of the projects CGL2006-11619/HID, CGL2011-27753-C02-01 and CGL2012-35858, funded by the Spanish Ministry of Economy and Competitiveness. The research group on Geomorphology and Global Change was financed by the Aragón Government and the European Social Found (ESF-FSE) (E68). The authors acknowledge Dr David Fink, Dr Magali Delmas and an anonymous reviewer for their valuable comments on the manuscript. We also particularly thank Dr Irene Schimmelpfennig, whose collaboration was essential to the study. ; Peer reviewed

Purpose: Sediment delivery from headwater catchments to reservoirs is a serious threat to reservoir sustainability, and is a critical issue in Mediterranean environments where water resources are scarce. In this study we assessed the consequences of two landscape management scenarios (natural vegetation recovery and scrub clearance) on soil erosion and sediment yield. The results were analyzed in relation to predicted and measured rates of soil erosion and sediment yield, with the aim of promoting better management practices. Materials and methods: The study area was the Arnás River catchment (284 ha), which is located in the central Spanish Pyrenees; the area includes abandoned and poorly managed fields. The combination of the RUSLE and SEDD models of soil erosion and sediment delivery was evaluated in terms of its ability to predict annual rates of sediment yield, using field measurement data for seven water years at the gauging station. The consequences of natural plant succession in other areas of the Spanish Pyrenees, and scrub clearance practices implemented by certain regional governments to increase grazing meadow areas and reduce the incidence of wildfires, were spatially analyzed using GIS. The main sediment source areas were identified and their specific and total sediment yield rates were calculated. Results and discussion: The predicted soil loss under existing conditions was 2.6 Mg ha–1 yr–1, with 5% of the surface area affected by rates greater than 2 tons. The measured sediment yield (SY) range was 69–534 Mg yr–1. The maximum SY detected was associated with an extraordinary debris flow. The predicted rates were strongly correlated to measured rates (Nash–Sutcliffe coefficient = 0.72). The main sources of were alluvial deposits (Specific Sediment Yield = 51 Mg ha–1 yr–1), bare soil (SSY = 12), unpaved trails (SSY = 11), lots (SSY = 4) and pastures (SSY = 1). Under a scenario of vegetation recovery, decreases of 3, 17 and 16% in soil loss, and sediment delivery and yield (respectively) are predicted, whereas increases of 15, 5 and 2% are predicted following scrub clearance practices. Conclusions: Coupling the RUSLE and SEDD models enabled estimation of annual values of soil erosion and delivery in monitored and unmonitored catchments of small and medium size, making this approach a useful tool for risk analysis. Management practices that combine fire-risk control, by the implementation of scrub clearance practices, with the effects of plant succession on the sediment production are suggested as the best management strategy. ; Acknowledgements: This research was financially supported by the projects: "Soil erosion and carbon dynamic in Mediterranean agroecosystems: radioisotopic modelling at different spatial and temporal scales" (MEDEROCAR, CGL2008-00831/BTE), and "Processes and sediment balances at different spatial scales in Mediterranean environments: Effects of climate fluctuations and land use changes" (PROBASE, CGL2006-11619/HID), both funded by the Spanish Ministry of Science and Innovation. Monitoring of the catchment was supported by an agreement between the CSIC and the Spanish Ministry of Environment (RESEL). ; Peer reviewed

51 Pags.- 9 Figs. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-145X ; Soil erosion is a threat to food security, especially in regions where the area of arable land is shrinking dramatically because of soil degradation. Research on soil erosion expanded progressively throughout the 20th centu\ry, although a number of unresolved problems persist despite this issue being crucial for the environment and the welfare of society. Some basic unresolved issues, including the absence of a universally accepted definition of soil erosion and disagreement about how to measure it have contributed to a degree of scientific stagnation. Accurate prediction of the response of soils to disturbance is hampered by the dependence of the erosion process on the spatial scale involved, the time lag between the disturbance and the erosion response and the short periods for which data are typically available. We argue that devoting increased attention to the following environmental, demographic, political and societal issues will reinvigorate progress in the field. (i) The relationships between on-site and off-site consequences of soil erosion need to be elucidated if the economic and environmental costs are to be adequately assessed. (ii) Effective measures for soil conservation need to focus on spatial patterns of plant cover that reduce sediment connectivity, and most importantly on the relationships between hillslopes and sediment transfer in eroded channels. (iii) The scientific community must be able to identify early warning signs of critical transitions, if irreversible soil degradation is to be prevented. (iv) Consensus needs to be reached concerning the contribution of soil erosion to the carbon cycle. (v) The consequences of climate change on erosion and sediment transport should be investigated in depth. (vi) The general society needs to perceive soil erosion as a critical matter requiring an urgent response. ; This research was supported by the projects ESPAS (CGL2015-65569-R) and INDICA (CGL2011-27753-C02-01 and 02) (MINECO/FEDER). The research groups on "Geomorphology and Global Change" and "Climate, Water, Global Change and Natural Systems" were financed by the Aragón Government and the European Social Fund (ESF). E. Nadal-Romero was the recipient of a "Ramón y Cajal" postdoctoral contract (Spanish Ministry of Economy and Competitiveness). The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007–2013) under grant agreement no 603498 (RECARE project). ; Peer reviewed

50 Pag., 5 Tabl., 11 Fig. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1097-0088 ; Assessing the characteristics of extreme precipitation over large regions has a great interest, mainly due to its applications in hazard analysis. However, most of the analyses are reduced to daily rainfall intensity due to the fact that most long precipitation records were collected on a daily basis. Hazardous situations related to extreme precipitation events, however, can be originated either by very intense rainfall, or by large accumulated precipitation due to the persistence of the rainy conditions over a long period of time. In this paper, we show the use of a methodology based on the extreme-value theory to obtain continuous maps of quantiles of precipitation event parameters—peak intensity, magnitude and duration—for a large region with contrasted climatic characteristics in the northeastern Iberian Peninsula. Spatial models of the probability distributions parameters were calculated, which allowed constructing the regional probability models. The analysis was based on time series of precipitation events, which were obtained from the original daily series. In addition to the usual annual-based analysis, seasonal analyses were also performed. This allowed assessing the differences in the spatial distribution of the probability of extreme events at different times of the year. ; Funded by Spanish Commission of Science and Technology and FEDER. Grant Number: CGL2005-04508/BOS Aragón Government. Grant Number: PIP176/2005 Programa de grupos de investigación consolidados. Grant Number: BOA 48 of 20-04-2005 Ramón y Cajal Research Spanish Ministry of Science and Education ; Peer reviewed

An edited version of this paper was published by AGU. Copyright 2007 American Geophysical Union. To view the published open abstract, go to http://dx.doi.org and enter the DOI. ; This paper analyzes the influence of the extreme phases of the winter North Atlantic Oscillation (NAO) on water resources in the Spanish region of the Tagus River basin. By analyzing a winter NAO index based on station sea level pressure, the years between 1957 and 2003 were classified as normal, positive, and negative NAO years. A statistical test was then applied to monthly data series of precipitation, river discharge, reservoir storage, and reservoir release to analyze the variations in these variables. For all four variables, significant differences were found between positive and negative NAO years, the former resulting in reduced water availability (negative anomalies) and the latter resulting in increased water availability (positive anomalies). The influence of extreme NAO winters was found to act with different time lags on different variables: The effect of extreme NAO winters on precipitation was found to be quite immediate (and significant for December to March), but this effect was observed later in the year and lasted longer for river discharge, reservoir storage, and water release. Positive and negative NAO years were also found to have different effects on these variables, in that the effects of positive years were more sustained and those of negative years were more rapid and less prolonged. In spite of the high variability of the availability of water resources, the strategies for management of the reservoir system of the basin were found in most cases to provide a regular supply that meets water demands. However, our results also indicate that these water management practices are not adequate for the expected scenarios of climate change and increasing water demand. ; The study has been supported by the following projects: STRIVER (Strategy and methodology for improved IWRM - An integrated interdisciplinary assessment in four twinning river basins) financed by the European Commision (VI framework programme), CGL 2004-04919-C02-01, CGL2005-04508/BOS, CGL2006-11619/HID financed by the Spanish Commission of Science and Technology and FEDER, PIP176/2005, PM088/2006 and "Programa de grupos de investigación consolidados" (BOA 48 of 20-04-2005) financed by the Aragón Government. The research activities of the first author were supported by a postdoctoral grant from the Spanish Ministry of Education, Culture and Sports. ; Peer reviewed

14 Pags., 3 Tabls., 9 Figs. ; Soil erosion and sediment yield are strongly affected by land use/land cover (LULC). Spatially distributed erosion models are of great interest to assess the expected effect of LULC changes on soil erosion and sediment yield. However, they can only be applied if spatially distributed data is available for their calibration. In this study the soil erosion and sediment delivery model WATEM/SEDEM was applied to a small (2.84 km2) experimental catchment in the Central Spanish Pyrenees. Model calibration was performed based on a dataset of soil redistribution rates derived from point 137Cs inventories, allowing capture differences per land use in the main model parameters. Model calibration showed a good convergence to a global optimum in the parameter space, which was not possible to attain if only external (not spatially distributed) sediment yield data were available. Validation of the model results against seven years of recorded sediment yield at the catchment outlet was satisfactory. Two LULC scenarios were then modeled to reproduce land use at the beginning of the twentieth century and a hypothetic future scenario, and to compare the simulation results to the current LULC situation. The results show a reduction of about one order of magnitude in gross erosion (3180 to 350 Mg yr−1) and sediment delivery (11.2 to 1.2 Mg yr−1 ha−1) during the last decades as a result of the abandonment of traditional land uses (mostly agriculture) and subsequent vegetation recolonization. The simulation also allowed assessing differences in the sediment sources and sinks within the catchment. ; This work has been supported by the following research projects: MEDEROCAR (CGL2008-00831/BTE), EROMED (CGL2011-25486), and DISDROSPEC (CGL2011- 24185), financed by the Spanish Commission of Science and Technology (CICYT) and FEDER, ChangingRISKS (OPE00446/PIM2010ECR-00726), financed by EU ERA-NET CIRCLE Programme, and Grupo de Excelencia E68 financed by the Arag´on Government and FEDER. The research of M. A.-M. Contribution of L.-C. A. was made possible through a scholarship granted by The National Council for Science and Technology of Mexico (CONACYT). ; Peer reviewed

Badlands are landforms that occur all over the World. In the Mediterranean region, badlands are found in both dry (arid and semi‐arid) and wet (subhumid and humid) environments, and are characterized by complex hydro‐geomorphological dynamics, high intense erosion processes and extreme sediment yield. Understanding the impact of Global Change is key to predict the on‐site and off‐site effects on badland dynamics, particularly its consequences on bedrock weathering, on sediment yield and delivery and on plant colonization. Here, conducting a systematic literature review, we analyzed an extensive database and identified the main climate‐drivers affecting the hydro‐geomorphological dynamics in Mediterranean badlands (based on non‐metric multidimensional scaling and structural equation modeling analysis). Later, we examined the main impacts expected from climate change forecasting in the near future, and we explored the interactions between badlands response to climate variation. In Mediterranean badlands, weathering processes are mainly related to wetting–drying cycles and freeze–thaw cycles in dry and wet badlands, respectively. In both environments, rainfall amount appears as the main driver for runoff response, and rainfall amount and rainfall intensity for erosion dynamics. Future climate scenarios forecast a decrease in annual rainfall, number of rainfall events and frost days, and in soil moisture, and an increase in rainfall intensity. These changes will have direct hydro‐geomorphological implications with direct and indirect effects on badland dynamics. This may result in a decrease in annual runoff in dry badlands, but the occurrence of more frequent extreme events would increase soil erosion and could negatively affect biological soil crust. In wet badlands, weathering and erosion processes may decrease, and a stabilization of the slopes, with consequently improved vegetation growth, may be expected. In addition, the forecasted changes must be taken into account, especially considering the possible off‐site effects of these extreme environments. ; This work was funded by the H2020‐MSCA‐IF‐2018 program (Marie Sklodowska‐Curie Actions) of the European Union under REA grant agreement, number 834329‐SEDILAND, the REBIOARID (RTI2018‐101921‐B‐I00) and MANMOUNT (PID2019‐105983RB‐100/AEI/10.13039/501100011033) projects funded by the Spanish National Plan for Research (Ministerio de Ciencia e Innovación) and the European Union ERDF funds and the RH2O‐ARID project (P18‐RT‐5130) funded by Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía and the European Union ERDF funds. ERC and SC are supported by a HIPATIA‐UAL postdoctoral fellowship funded by the University of Almeria. ; Peer reviewed

66 Pag., 5 Fig. The definitive version is available at: http://www.sciencedirect.com/science/journal/00128252 ; Mediterranean areas of both southern Europe and North Africa are subject to dramatic changes that will affect the sustainability, quantity, quality, and management of water resources. Most climate models forecast an increase in temperature and a decrease in precipitation at the end of the 21st century. This will enhance stress on natural forests and shrubs, and will result in more water consumption, evapotranspiration, and probably interception, which will affect the surface water balance and the partitioning of precipitation between evapotranspiration, runoff, and groundwater flow. As a consequence, soil water content will decline, saturation conditions will be increasingly rare and restricted to periods in winter and spring, and snow accumulation and melting will change, especially in the mid-mountain areas. Future land management will be characterized by forest and shrub expansion in most Mediterranean mountain areas, as a consequence of farmland and grazing abandonment, with increasing human pressure localized only in some places (ski resort and urbanized of valley floors). In the lowlands, particularly in the coastal fringe, increasing water demand will occur as a consequence of expansion of irrigated lands, as well as the growth of urban and industrial areas, and tourist resorts. Future scenarios for water resources in the Mediterranean region suggest (1) a progressive decline in the average streamflow (already observed in many rivers since the 1980s), including a decline in the frequency and magnitude of the most frequent floods due to the expansion of forests; (2) changes in important river regime characteristics, including an earlier decline in high flows from snowmelt in spring, an intensification of low flows in summer, and more irregular discharges in winter; (3) changes in reservoir inputs and management, including lower available discharges from dams to meet the water demand from irrigated and urban areas. Most reservoirs in mountain areas will be subject to increasing water resource uncertainty, because of the reduced influence of snow accumulation and snowmelt processes. Besides, reservoir capacity is naturally reduced due to increasing sedimentation and, in some cases, is also decreased to improve the safety control of floods, leading to a reduction in efficiency for agriculture. And (4) hydrological and population changes in coastal areas, particularly in the delta zones, affected by water depletion, groundwater reduction and saline water intrusion. These scenarios enhance the necessity of improving water management, water prizing and water recycling policies, in order to ensure water supply and to reduce tensions among regions and countries. ; This work was supported by research projects CGL2006-11619/HID, CGL2008-01189/BTE, and CGL2008-1083/CLI, financed by the Spanish Commission of Science and Technology, and FEDER, EUROGEOSS (FP7-ENV-2008-1-226487) and ACQWA (FP7-ENV-2007-1-212250, financed by the European Commission, the VII Framework Programme financed by the European Commission, the project "Las sequías climáticas en la cuenca del Ebro y su respuesta hidrológica" and "La nieve en el Pirineo aragonés: Distribución espacial y su respuesta a las condiciones climáticas", financed by "Obra Social La Caixa" and the Aragón Government, and "Programa de grupos de investigación de excelencia", financed by the Aragón Government. ; Peer reviewed