Twenty-five years after planting, we measured the survival, growth and reproduction of 153 Quercus ilex plantations promoted by the afforestation programme of the European Union’s Common Agricultural Policy in agricultural fields in the east of the Iberian Peninsula, as a function of climatic aridity and stand characteristics related to water supply and competition among trees for water. Using field sampling, we found that, on average, 80% of the trees in plantations survived, more than 55% had already produced acorns and the tallest tree in each field exceeded 4 m, which are all higher values than those reported for forest plantations of this species in the same area and which represent the overcoming of the limitations imposed by climatic aridity on the natural regeneration of the species. A small proportion of the variation in all success variables was explained by water-related plantation characteristics, such as planting density, drought intensity in the year after planting, and soil permeability. However, climatic aridity only influenced the proportion of reproductive trees, but not the other variables of plantation success. However, most of the variation in planting success variables was linked to who owned the field, which nursery produced the seedlings, and the year of planting. Our results support the idea that the deep soils of agricultural fields counteract the negative effect of climatic aridity on plant performance, but that it is necessary to standardise nursery and planting practices, adapt planting density to the environmental characteristics of the site and provide irrigation supply in the early years to ensure the success of future plantations.

Facilitation is an ecological interaction that has allowed plant lineages to survive past climate aridification. This same interaction can be expected to buffer the effects of current climate change, which is tending to become more arid in the Mediterranean basin. However, facilitation may wane when stress conditions are extreme. Here we argue that the erosion of the facilitation signal between Quercus ilex and its nurses detected by García‐Fayos et al. (2020) along 50 years in the eastern Iberian Peninsula may have been due to the reversion of facilitation to competition imposed by an increasingly arid climate. To support this speculation, we reconstructed the climatic niche of Q. ilex and its nurses as well as the local climate change occurring in the populations studied. We found that the decreasing trend in precipitation is pushing Q. ilex out of its climatic optimum in the stressful (semi‐arid) but not in the mild (sub‐humid) habitats. These results suggest that facilitation will be unable to mitigate the effects of climate change, especially those related to aridification. However, other scenarios linking climatic change with herbivory and rural abandonment should be considered to fully understand the past, present and future of facilitation interactions. Reconstructing past interactions can serve as an early warning signal about the future of populations in the face of climate change.

The organization and function of forest ecosystems is changing at an unprecedent rate under the influence of external drivers, such as climate change and human uses. In this context of change, the increasing frequency, intensity and duration of droughts that affect the Mediterranean basin urges to evaluate forest vulnerability to drought and their effects for the long-term stability of these ecosystems. In this study, we explore the responses and factors that control the resilience of holm oak (Quercus ilex) woodlands to recent extreme droughts during 2000-2019, using a remote sensing approach over a broad scale climate aridity gradient that extends from sub-humid to semi-arid climate conditions over 100,000 km2 in eastern Spain. Overall, our results indicated that climate aridity and forest structure largely control the resistance, recovery and resilience of the studied holm oak woodlands to drought, which are also affected by drought intensity and both pre- and post-drought hydric conditions. We found that Q. ilex woodlands located in the dry edge of the explored climate aridity gradient showed a high sensitivity to extreme drought. Their resistance, assessed as the capacity of the woodlands to maintain primary production during drought, was low. They also showed a poor resilience, characterized by a low capacity to fully recover their pre-drought production levels. Contrarily, holm oak woodlands in sub-humid areas of the study region, where wetter climate conditions may alleviate water stress during dry periods, showed a high resistance and resilience to the effects of droughts. Drought vulnerability was particularly high for dense holm oak stands developed under semi-arid climate conditions, where strong competition for scarce water resources largely increased the negative effects of extreme drought on landscape-level ecosystem production. We also discuss the implications of these results for adaptive management of holm oak forests in the present context of climate change.

Understanding how Mediterranean forests respond to the increasing frequency of extreme droughts and forest densification is crucial for effective land management in the present context of climate change and land abandonment. We study the responses of Iberian holm oak (Quercus ilex L.) woodlands to recent extreme droughts during 2000-2019 along broad gradients of climate aridity and forest structure. To this purpose, we apply largescale remote-sensing using MODIS EVI as a primary production proxy in 5274 Q. ilex sites distributed within a 100,000 km2 region in eastern Spain. These woodlands were extensively affected by two extreme drought events in 2005 and 2012. Resistance, assessed as the capacity of the ecosystems to maintain primary production during drought, was significantly lower for semi-arid than for sub-humid and dry-transition conditions. Holm oak woodlands located in semi-arid areas of the region showed also poorer resilience to drought, characterized by low capacity to fully recover to their pre-drought production levels. Further, drought intensity and both pre- and post-drought hydric conditions controlled the variations of resistance, recovery and resilience between the two analyzed extreme drought events. Drought effects were particularly negative for dense Q. ilex stands under semiarid climate conditions, where strong competition for scarce water resources reduced drought resistance. The observed drought vulnerability of semi-arid holm oak woodlands may affect the long-term stability of these dry forests. Adaptive management strategies, such as selective forest thinning, may be useful for improving drought responses in these more vulnerable semi-arid woodlands. Conversely, natural rewilding may more appropriately guide management actions for more humid areas, where densely developed Q. ilex woodlands show in general a high ability to maintain ecosystem primary production during drought.

The use of ecohydrologically suitable microsites, such as sink patches (i.e. zones intercepting and infiltrating runoff) and nurse shrubs, have largely been proposed as tools to improve the establishment of late-successional trees in Mediterranean reclaimed landscapes. Nonetheless, this technique needs to be accurately tested along with the influence of seedling water-use strategy. To that purpose, we monitored the short- and mid-term (i.e. 4 and 8 years, respectively) influence of sink patches and nurse shrubs (Genista scorpius) on seedlings of two species with contrasted water-use strategies, Pinus nigra, a more drought avoider and isohydric species, and Quercus ilex, a more drought tolerant and anisohydric species. In the short term, G. scorpius shrubs enhanced the establishment of seedlings planted in shaded spots under its canopy. This positive interaction was more relevant for Q. ilex in drier years, while P. nigra was more facilitated in wetter years. Sink patches ameliorated the survival of both species, but only promoted greater growth during wetter years. P. nigra seedlings showed a high sensitivity to precipitation reduction. Their survival and growth were strongly constrained in dry years, resulting in a very high cumulative mortality at the end of the 8-year study period regardless of the microsite the seedlings were planted in. Q. ilex showed better seedling performance than P. nigra in the mid-term, keeping also the positive effects of suitable microsites on plant survival in the mid-term, after 8 years of plantation. Our results support the use of suitable microsites that ameliorate ecohydrological conditions as key spots for enhancing ecological succession in reclaimed mining sites, particularly the use of G. scorpius as nurse shrub for improving Q. ilex seedling establishment and growth. Our results also suggest that seedling functional strategy to cope with drought is a critical factor conditioning the overall plantation performance in the mid-term. Thus, seedling water-use strategy should constitute a key species selection criteria in future restoration programs focused on Mediterranean ecosystems, especially under climate change.

Empirical evidence of the vulnerability of dryland ecosystems to suffer abrupt changes in response to global change is highly needed to assess the applicability of threshold models, understand the underlying mechanisms and anticipate the onset of abrupt shifts. We study the onset of abrupt changes in Mediterranean holm oak (Quercus ilex) woodlands, by analyzing the combined effect of past human disturbance (mainly deforestation) and aridity on the functional state of these ecosystems. We determine ecosystem state in terms of herbaceous/woody species ratio, species richness and soil properties related to carbon and nitrogen cycling and microbial activity. The influence of both drivers was determined along spatial gradients of past human disturbance (from lightly to highly disturbed areas) and aridity (three levels: sub-humid, dry-transition, semi-arid). Our results show a strong interaction between aridity and past human disturbance on soil and vegetation properties. As disturbance increased, soil function decreased linearly in semi-arid and dry-transition conditions, but the trend was non-linear in sub-humid conditions. The latter showed a sharp decline at low-to-moderate disturbance intensity followed by a gentle recovery at higher intensities. These patterns were consistent for all soil properties. Structural changes in vegetation along the disturbance gradient, from open woodlands to shrublands in semi-arid and dry-transition conditions and from dense woodlands to grasslands in sub-humid conditions accompanied the linear vs non-linear patterns in soil function, respectively. Our results evidenced the existence of a critical climatic threshold in the boundary between sub-humid and dry-transition conditions, where the ecosystem switched from a fertile grassland to a highly degraded shrubland at moderate-to-high levels of disturbance (shrub encroachment), losing its capacity to buffer the effects of increasing disturbance. We propose a conceptual model illustrating the ecological mechanisms that may be underlying the onset of such abrupt shift.

Time Domain Reflectometry (TDR) is a widely used technique to estimate the soil volumetric water content (theta) and bulk electrical conductivity (sigma). This paper presents TDR-WiFi, a wireless, portable and low cost interface to ease sensing of theta and sigma by connecting TDR cable tester with a smartphone. TDR-WiFi consists of a microprocessor equipped with a WiFi microcontroller (M5Stack unit) and connected to the TDR device through an RS232-TTL adapter. The M5stack firmware is programmed in MicroPython language to act as a server between the user and the TDR device through a web page accessible from any smartphone web browser. TDR-WiFi is compatible with the Campbell TDR100 device and allows storing the TDR waveforms as well as estimating theta and sigma. A complementary web page for subsequent analysis of the TDR waveforms was developed and is publicly available at http://swi.csic.es/tdrwifi/. The system was satisfactorily demonstrated in laboratory and tested in the field. The field trial allowed water content measurements in a steep road slope. TDR-WiFi demonstrated to be operative in the field and it can be satisfactorily used in difficult access areas.

This research documents the successful application of a novel holistic approach to return land degraded over thousands of years of use to full ecological function. The surroundings of the Somolinos hamlet in Central Spain illustrate a millennial history of land transformation and degradation by agrarian and extractive activities exacerbated at the second half of the 20th century by mechanized mining. This land stewardship history was culminated by a recent intervention of geomorphic-based ecological restoration and its monitoring. Historic anthropogenic processes which triggered gully erosion were intense deforestation for agriculture and grazing, and construction materials quarrying. From 1963 to 2006 mechanized quarrying operated over ancient extractive landforms. In 2007, a conventional rehabilitation mitigated risks but failed at controlling erosion and promoting soil and vegetation reestablishment. A geomorphic-based ecological restoration was accomplished since 2011. The GeoFluv-Natural Regrade CAD software was used for geomorphic landform design, and construction was completed with a carbonatic colluvium topdressing supplemented with a manure-amended soil, that was seeded with grasses. The whole process was a truly complete application of ecological engineering. One of the main purposes of this research was to carefully scrutinize the completed project, to evaluate its effectiveness and, if any deficiencies were found, to analyze their causes, so that they could be avoided in the future. Therefore, the landscape evolution and erosional behaviour of the restored area has been monitored from 2011 to 2020 through a time-lapse sequence of several oblique aerial photos, and by comparing topographies through Digital Elevation Models (DEMs) of Difference (DoDs). Those topographies were surveyed with differential GPS (DGPS) and with Structure from Motion (SfM) combined with Unmanned Aerial Vehicles (UAVs). This monitoring revealed: (a) landscape healing and diversification of the vegetation community composition and structure, as a result of the environmental heterogeneity of the geomorphic design; and (b) absence of hillslope and channel erosion for 99.8% of the area with limited surface erosion zones in 0.2% of the restored area. Our analysis attributed those limited erosion zones to a combination of: (a) minor design oversights; (b) slight construction deviation from the design grade; and (c) excessive runoff entering the repaired area that exceeded the design discharge. These erosion zones started to stabilize five years after initial restoration and achieved steady-state stability at nine years. The main lesson learnt from these minor deficiencies is that such erosion zones can be avoided at the design phase within GeoFluv-Natural Regrade by checking proper convex-concave slopes and concave channel profiles and by carefully considering any adjacent runoff entering the designed areas, which influence the channel's tractive forces. The use of Landscape Evolution Models, such as SIBERIA, can also identify design anomalies subject to erosion. Then, after rigorously inspecting the design, it is imperative that the construction is completed true to the design by defining and following construction tolerances.

Time Domain Reflectometry (TDR) is an accurate and widely used technique for real time estimation of soil volumetric water content (θ), and the bulk electrical conductivity (σ). Although there are multiple software that allow monitoring θ and σ by connecting the TDR device to a PC, this system used under field conditions can be in many cases awkward. This paper presents a wireless, portable, unexpansive, simple, and versatile system to measure θ and the σ by connecting the TDR device to a smart phone. The system consists on a M5Stack processing unit that integrates a Wifi connectivity. The UART port of the M5Stack is connected to the TDR device through RS232-ttl adapter. The hardware is programmed in micropython language that allows the M5Stack acts as a server between the user and the TDR device through a web page read with a smart phone. The software, which is compatible with Campbell TDR100 and 1502C Tektronix devices, allows creating different project where the TDR waveforms are stored. A simple θ and the σ measurement is also allowed. Since the objective of the portable system is to ease and makes θ and σ samplings faster, a complementary web page for subsequent and more accurate estimates of θ and σ was also developed.

Opencast mining is an activity that caters to many economic sectors; however, it has a large impact on society and the environment. After mining, the major concern is to restore the previous land cover, which was generally a natural vegetation cover. Establishing permanent vegetation cover can restore landscape connectivity and previous ecosystem functions, enhance aesthetic values and prevent off-side effects associated with post-mining landscapes. Opencast mining reclamation deals with these issues with several strategies that aim to develop a vegetation cover after mining activity has stopped. However, not all reclamation actions are effective, and assessing their efficiency by monitoring vegetation development at reclaimed sites is a time-consuming task because it usually involves extensive field work. In this study, we present a semi-automatic approach based on analysing satellite data (Landsat) time series and using a machine learning technique to identify suitable conditions for vegetation development at reclaimed opencast mines. We analysed the Teruel coalfield (Aragón, central-eastern Spain). This area is a representative Mediterranean-Continental region that is of particular interest due the diversity of reclamation actions that have been applied and the increase in drier conditions during the last decades. Conditions were described with topography derived variables, technical reclamation features and drought-occurrence variables as potential explanatory factors. The implemented approach allowed us to identify the main abiotic filters for vegetation of this geographic region: the water availability and soil retention (both controlled by the topographic slope), and the proximity to seed sources. The analysis evidenced the negative influence of drought occurrence on vegetation development, and different responses were found depending on the timescale at which drought is calculated. Our results indicate that the reclamation landform model is the main key factor influencing vegetation development. A model such as the smooth berm-slope increases water availability and controls soil erosion, and hence, improves vegetation development. In addition, we found that further than 500-600 m from the mine, the effect of seed source declines dramatically. Therefore, all these issues should be considered in future reclamation designs in a Mediterranean-Continental environment. Our methodology could be adapted to other geographic regions where spatial environmental data are available.

ABSTRACT Geomorphic-based mine restoration of clay quarries in Tortosa (Catalonia) was co-funded by the European Union’s LIFE programme. The landform design was made with GeoFluv-Natural Regrade. Their building was performed with existing machinery pool and operators. The main constraint was the impossibility of setback regrading of pre-existing-benched highwalls. Progressive geomorphic mine restoration neither reduced mineral production nor changed the operations. The approach has resulted in higher landscape functionality and integration. Monitoring showed localised erosion due to poorly planned discharge of road runoff and sporadic tunnel erosion. Sediment movement at the designed drainage network is similar to the local fluvial dynamics.

Connectivity has emerged as a useful concept for exploring the movement of water and sediments between landscape locations and across spatial scales. In this study, we examine the structural and functional controls of surfacepatch to hillslope runoff and sediment connectivity in three Mediterranean dry reclaimed mining slope systems that have different long-term development levels of vegetation and rill networks. Structural connectivity was assessed using flow path analysis of coupled vegetation distribution and surface topography, providing field indicators of the extent to which surface patches that facilitate runoff and sediment production are physically linked to one another in the studied hillslopes. Functional connectivity was calculated using the ratio of patch-scale to hillslope-scale observations of runoff and sediment yield for 21 monitored hydrologically active rainfall events. The impact of the dynamic interactions between rainfall conditions and structural connectivity on functional connectivity were further analysed using general linear models with a backward model structure selection approach. Functional runoff connectivity during precipitation events was found to be dynamically controlled by antecedent precipitation conditions and rainfall intensity and strongly modulated by the structural connectivity of the slopes. On slopes without rills, both runoff and sediments for all events were largely redistributed within the analysed hillslopes, resulting in low functional connectivity. Sediment connectivity increased with rainfall intensity, particularly in the presence of rill networks where active incision under high-intensity storm conditions led to large non-linear increases in sediment yield from the surface-patch to the hillslope scales. Overall, our results demonstrate the usefulness of applying structuraland functional-connectivity metrics for practical applications and for assessing the complex links and controlling factors that regulate the transference of both surface water and sediments across different landscape scales.

Estimation of the alpha and n van Genuchten (1980) parameters and the saturated hydraulic conductivity, K-s, of undisturbed soil samples is critical for realistic water flow simulations in the vadose zone. Given the Latorre and Mores-Fernandez (2019) method, which allows estimating K-s, alpha and n from the inverse analysis of a single upward infiltration, the objective of this work is to advance on the theoretical understanding of this method and to apply it on undisturbed soil cores. To this end, the influence of the saturated, theta(s), and residual, theta(r), water content and initial soil tension, h(i), on the alpha, n and K-s optimization was first studied on synthetic soils. A procedure to simultaneously estimate 0(s), alpha, n and K-s, which consisted on optimizing alpha, n and K-s for a range of 0(s) values, was proposed. To this end, alpha, n and K-s were optimized leaving each theta(s) as a fixed value. The method was next applied to experimental curves measured from sieved and undisturbed soil cores of 50 mm high and diameter, sampled the last ones from three fields with different management bare vs. under plant soil; agricultural soil under conservation vs. conventional tillage; and overburden soil from mine vs. topsoil formed by the original soil. Results showed that theta(s) had an important effect on alpha, n and K-s optimization, where the minimum error within the selected theta(s) interval corresponded to the theoretical theta(s) An important effect of h(i) on the optimization was also observed. However, this influence was omitted by using a h(i) value located in the theta(r) region, where do d theta/dh approximate to 0. Under this assumption, theta(r) only affected the theta(s) optimization, which value varied with theta(s). A robust relationship (R-2 = 0.99; p < 0.0001) was found between theoretical and optimized theta(s), K-s and alpha and n calculated for the synthetic soils. Thus, the method allowed estimating four of the five van Genuchten (1980) parameters. An absolute minimum was also observed when the method was applied on experimental infiltration curves. The theta(s) measured gravimetrically on the undisturbed samples was, on average, 8.1% higher than the optimized one. Overall, the method allowed detecting significant differences (p < 0.05) in hydraulic properties between bare and under plant soils and among tillage treatments. The large variability found in the mine's soils prevented to find significant differences within this scenario.

Soil sorptivity, S, and saturated hydraulic conductivity, K-s, can be estimated from the inverse analysis of a disc infiltrometer cumulative infiltration curve using the quasi-exact implicit (QEI) analytical Haverkamp et al. (1994) equation, which is a function of K-s, S, the parameters beta and gamma, the disc radius, r(d), and the water content increase, increment theta. Given the complexity of solving QEI, this paper presents three-term, 3T, and four-term, 4T, QEI expansions to estimate S and K-s. The interplays between beta, gamma, K-s and S employing S-K-s, gamma-K-s, gamma-S, gamma-beta, S-beta and K-s-beta error maps generated for a loam soil synthetic infiltration were analyzed with QEI. To reduce the number of variables, Delta theta, r(d) and gamma were packed into the A=gamma rd increment theta term. Five different QEI expansion analyses were evaluated: (i and ii) optimization of 3T using A, 3T(A), or beta, 3T(beta), as fixed variables; (iii and iv) optimization of 3T, 3T(A beta), and 4T, 4T(A beta), using constant beta and A values; and (v) optimization of 4T leaving all coefficients free, 4T(F). The different methods were evaluated with synthetic infiltrations for homogeneous sand, loam and silt soils, and for an uniform loam soil with a contact sand layer. The QEI expansions were applied to experimental infiltrations, and the results were compared to those obtained with QEI, using beta = 0.6 and gamma = 0.75. Infiltrations were performed at zero cm of soil tension. Global optimization with QEI demonstrates that gamma and beta are extremely linked. This makes it difficult to estimate these two parameters. All procedures applied to synthetic homogeneous soils resulted in good K-s and S approaches. However, only 3T(A), 3T(A beta) and 4T(A beta) obtained accurate estimates of K-s and S when applied to a synthetic homogeneous soil with a contact sand layer. Application of the different methods to the experimental infiltrations showed that 3T(A beta) and 4T(A beta) gave the most accurate and robust estimates of S and K-s.

Knowledge of the recruitment of dominant forest species is a key aspect for forest conservation and the ecosystem services they provide. In this paper, we address how the simultaneous action of climate change and the intensity of land use in the past influence the recruitment of a forest species that depends on the provision of nurse plants to recruit. We compared the number of saplings (up to 15 years old) and juveniles (16 to 50 years old) of Quercus ilex in 17, 5.3 ha plots in the Iberian System (eastern Spain). We used a gradient of past deforestation intensity crossed with two levels of average annual precipitation, one of them at the lower limit of the species' precipitation niche (semi-arid) and the other at the optimum (sub-humid). We also examined the association between recruits and nurse plants and the effect on this association of plot-scale factors, such as seed abundance (reproductive Q. ilex), microsites (nurse species and soil availability), and large herbivores. The increase in aridity in the last decades has drastically reduced the recruitment of new individuals in the forests of Q. ilex located in the lower limit of their precipitation niche, regardless of the intensity of past deforestation that they suffered. Recruitment in these climatic conditions depends almost exclusively on large trees and shrubs whose abundance may also be limited by aridity. The lack of regeneration questions the future of these populations, as the number of individuals will decrease over time despite the strong resistance of adult trees to disturbance and drought.

Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.

Geomorphic rehabilitation ([GR], also known as geomorphic reclamation or geomorphic restoration) is a general term to describe alternative methods and procedures to conventional mine rehabilitation.The main aim of GR is to replicate 'natural' landforms for the new conditions after mining and to restore functionality and diversity of ecosystems at degraded sites.The correct application of the GR technique ensures visual integration with surrounding landscapes.Although GR is a broad term, referring to any geomorphic restoration of land, GR is often synonymous with fluvial GR, mostly following the GeoFluv TM -Natural Regrade method.

This research describes a geomorphic-based process of mining reclamation carried out at the El Machorro mine (at the edge of the Alto Tajo Natural Park, East Central Spain) and its monitoring for five years (2012-2017). The GeoFluv T method implemented by the Natural Regrade software has been used to design small watersheds as a mining reclamation topographical solution. The procedure included: (i) finding a suitable reference area with stable landforms and acquiring inputs from them; (ii) designing two first-order stream watersheds; (iii) building the planned landscape; and (iv) monitoring the hydrological and erosive -sedimentary response of the reclaimed watersheds. This process is in itself a contribution to global advancement of reclamation best practices, because there are very few geomorphic-based mining reclamation examples, and even fewer that include their multiannual monitoring. Sediment yields were obtained comparing Digital Elevation Models (DEM) acquired by Total Station (TS), Terrestrial Laser Scanning (TLS), differential Global Positioning System (GPS) and topographic reconstructions (interpretations). An H-flume with turbidity and water pressure sensors allowed quantifying runoff and suspended sediment. Sediment yield progressively decreased with time attaining a current low value (4.02 Mg ha(-1) yr(-1)). Water discharge and suspended sediment concentration have also decreased with time. Initially, high sediment yield values were obtained. They are interpreted as being triggered by grading errors that deviated from the design, so that runoff adjusted construction irregularities during that period by erosion and sedimentation. After those adjustments, the reclamation surface became more reflective of the design and the resulting surface remained very 'stable'. The deduction is that the geomorphic-based reclamation has re-established an approximate steady-state or dynamic equilibrium, where hydrological and erosive -sedimentary functionality operate now at rates comparable to the surrounding natural land. Although further research is required to confirm long-term stability, geomorphic reclamation appears as an efficient mining reclamation alternative solution to the traditional approach of gradient terraces and downdrains, which require frequent and costly maintenance, in the highly erodible setting of the Alto Tajo Natural Park surroundings, as well as in most open pit mines.

The effects of ecosystem degradation are pervasive worldwide and increasingly concerning under the present context of global changes in climate and land use. Theoretical studies and empirical evidence increasingly suggest that drylands are particularly prone to develop nonlinear functional changes in response to climate variations and human disturbance. Precipitation-use efficiency (PUE) represents the ratio of vegetation production to precipitation and provides a tool for evaluating human and climate impacts on landscape functionality. Holm oak (Quercus ilex) woodlands are one of the most conspicuous dry forest ecosystems in the western Mediterranean basin and present a variety of degraded states, due to their long history of human use. We studied the response of Iberian holm oak woodlands to human disturbance along an aridity gradient (that is, semi-arid, dry-transition and sub-humid conditions) using PUE estimations from enhanced vegetation index (EVI) observations of the Moderate-Resolution Imaging Spectroradiometer (MODIS). Our results indicated that PUE decreased linearly with disturbance intensity in sub-humid holm oak woodlands, but showed accelerated, nonlinear reductions with increased disturbance intensity in semi-arid and dry-transition holm oak sites. The impact of disturbance on PUE was larger for dry years than for wet years, and these differences increased with aridity from sub-humid to dry-transition and semi-arid holm oak woodlands. Therefore, aridity may also interact with ecosystem degradation in holm oak woodlands by reducing the landscape ability to buffer large changes in vegetation production caused by climate variability.

Trabajo presentado en TERRAenVISION Environmental Issues Today: Scientific Solutions for Societal Issues, celebrado en Barcelona (Espana) del 27 de enero al 2 de febrero de 2018