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Digital Elevation Models (DEMs) are 3D representations of the Earth&rsquo, s surface and have numerous applications in geomorphology, hydrology and ecology. Structure-from-Motion (SfM) photogrammetry using photographs obtained by unmanned aerial vehicles (UAVs) have been increasingly used for obtaining high resolution DEMs. These DEMs are interpolated from point clouds representing entire landscapes, including points of terrain, vegetation and infrastructure. Up to date, there has not been any study clearly comparing different algorithms for filtering of vegetation. The objective in this study was, therefore, to assess the performance of various vegetation filter algorithms for SfM-obtained point clouds. The comparison was done for a Mediterranean area in Murcia, Spain with heterogeneous vegetation cover. The filter methods that were compared were: color-based filtering using an excessive greenness vegetation index (VI), Triangulated Irregular Networks (TIN) densification from LAStools, the standard method in Agisoft Photoscan (PS), iterative surface lowering (ISL), and a combination of iterative surface lowering and the VI method (ISL_VI). Results showed that for bare areas there was little to no difference between the filtering methods, which is to be expected because there is little to no vegetation present to filter. For areas with shrubs and trees, the ISL_VI and TIN method performed best. These results show that different filtering techniques have various degrees of success in different use cases. A default filter in commercial software such as Photoscan may not always be the best way to remove unwanted vegetation from a point cloud, but instead alternative methods such as a TIN densification algorithm should be used to obtain a vegetation-less Digital Terrain Model (DTM).

This research aimed to estimate the splash erosion and its evolution during the first months in specific land uses after a forest fire. The study area was located in Congosto (North-West Spain), in the margins of Spanish drylands, after a wildfire occurred in May 2012, which burned 15.56 ha of scrubland and Pinus reforestation. Two different burned land uses were selected and compared to control areas: i) burned pine forest; and, scrublands. Rainfall intensity and the number, sizes and speed of raindrops were measured by an optical disdrometer and soil loss by funnels. Moreover, infiltration, soil moisture content, aggregate stability, water repellence, pH and organic matter were also measured. Results showed that the highest soil losses occurred in the burned areas, especially in the scrubland plots. The most influential factors were the presence of bare soil and the low vegetation recovery rate. Changes in soil properties did not significantly influence splash erosion, although an increase in the presence of smaller classes of aggregates could promote erosion in the scrubland. We conclude that the vegetation ecosystem restoration is the key issue to be considered after a wildfire, especially, in those types of land uses which are severely affected by the fire in the margins of drylands.

Hydrological connectivity describes the physical coupling (linkages) of different elements within a landscape regarding (sub-) surface flows. A firm understanding of hydrological connectivity is important for catchment management applications, for e.g. habitat and species protection, and for flood resistance and resilience improvement. Thinking about (geomorphological) systems as networks can lead to new insights, which has also been recognised within the scientific community, seeing the recent increase in the use of network (graph) theory within the geosciences. Network theory supports the analysis and understanding of complex systems by providing data structures for modelling objects and their linkages, and a versatile toolbox to quantitatively appraise network structure and properties. The objective of this study was to characterise and quantify overland flow connectivity dynamics on hillslopes in a humid sub-Mediterranean environment by using a combination of high-resolution digital-terrain models, overland flow sensors and a network approach. Results showed that there are significant differences between overland flow connectivity on agricultural areas and semi-natural shrubs areas. Significant positive correlations between connectivity and precipitation characteristics were found. Significant negative correlations between connectivity and soil moisture were found, most likely due to soil water repellency and/or soil surface crusting. The combination of structural networks and dynamic networks for determining potential connectivity and actual connectivity proved a powerful tool for analysing overland flow connectivity.

Knowledge about connectivity and what affects it, through space and time, is needed for taking appropriate action at the right place and/or time by stakeholders. Various conceptual frameworks for hydrological and sediment connectivity have been developed in recent years. For most of these frameworks, the objective was to conceptualise connectivity, not necessarily to infer it from measurements. Studies focussing on measurements of connectivity have so far not been done often. Because of lack of data on connectivity, few real-world data have been used in recent connectivity modelling studies. The aim of this study was to demonstrate that existing data can be used to assess governing factors of connectivity, and how these change over time. Data from three catchments in Navarre, Northern Spain, were used to assess factors that influence hydrologic and sediment connectivity. These factors were used as components in a linear model for discharge and suspended-sediment yield. Three components of connectivity were distinguished: topographical, biological and soil. Changes in the topographical component for the studied periods were considered relatively small, and, therefore, kept constant. Changes in the biological component were determined using the Normalised Difference Vegetation Index. Changes in the soil component were assessed using an Antecedent Precipitation Index. Nash–Sutcliffe model efficiency coefficients were between 0·49 through 0·62 for the discharge models and between 0·23 through 0·3 for the sediment-yield models. We recommend applying the model at smaller spatial scales than catchment scale to minimise the lumping of spatial variability in the components. Copyright © 2016 John Wiley & Sons, Ltd.

Forest fires are a recurrent phenomenon in Mediterranean forests, with impacts for human landscapes and communities, which must be understood before they can be managed. This study used the physically based Limburg Soil Erosion Model (LISEM) to simulate rainfall–runoff response, under soil water repellent (SWR) conditions and different stages of vegetation recovery. Five rainfall–runoff events were selected, representing wet and dry conditions, spread over two years after a wildfire which burned eucalypt and maritime pine plantations in the Colmeal experimental micro-catchment, central Portugal. Each event was simulated using three Leaf Area Index (LAI) estimates: indirect field-based measurements (TC–LAI), NDVI-based estimates derived from Landsat-5 TM and Landsat-7 ETM+ imagery (NDVI–LAI), and the LAI of a fully restored canopy to test model sensitivity to interception parameters. LISEM was able to simulate events in relative terms but underestimated peak runoff (r 2 = 0·36, mean error = −31%, and NSE = −0·15) and total runoff (r 2 = 0·52, mean error = −15% and NSE = 0·09), which could be related to the presence of SWR or saturated areas, according to pre-rainfall soil moisture conditions. The model performed better for individual hydrographs, especially under wet conditions. Modelling the full-cover scenario showed minor sensitivity of LISEM to the observed changes in LAI. NDVI–LAI data gave a close to equal model performance with TC–LAI and therefore can be considered a suitable substitute for ground-based measurements in post-fire runoff predictions. However, more attention should be given to representing pre-rainfall soil moisture conditions and especially the presence of SWR. Copyright © 2016 John Wiley & Sons, Ltd.

Datasets containing large numbers (>10,000) of glacial lineaments are increasingly being mapped from remotely sensed data in order to develop a palaeo-glacial reconstruction or ”inversion”. The palimpsest landscape presents a complex record of past ice flow and deconstructing this information into a logical history is an involved task. One stage in this process requires the identification of sets of genetically linked lineaments that can form the basis of a reconstruction. This paper presents a semi-automated algorithm, CLustre, for lineament clustering that uses a locally adaptive, region growing, methodology. After outlining the algorithm, it is tested on synthetic datasets that simulate parallel and orthogonal cross-cutting lineaments, encompassing 1,500 separate classifications. Results show robust classification in most scenarios, although parallel overlap of lineaments can cause false positive classification unless there are differences in lineament length. Case studies for Dubawnt Lake and Victoria Island, Canada, are presented and compared to existing datasets. For Dubawnt Lake 9 out of 14 classifications directly match incorporating 89% of lineaments. For Victoria Island 57 out of 58 classifications directly match incorporating 95% of lineaments. Differences are related to small numbers of unclassified lineaments and parallel cross-cutting lineaments that are of a similar length. CLustre enables the automated, repeatable, assignment of lineaments to flow sets using defined user criteria. This is important as qualitative visual interpretation may introduce bias, potentially weakening the testability of palaeo-glacial reconstructions. In addition, once classified, summary statistics of lineament clusters can be calculated and subsequently used during the reconstruction process.

Most of the Earth's Ecosystem Services (ESs) have experienced a decreasing trend in the last few decades, primarily due to increasing human dominance in the natural environment. Identification and categorization of factors that affect the provision of ESs from global to local scales are challenging. This study makes an effort to identify the key driving factors and examine their effects on different ESs in the Sundarbans region, India. We carry out the analysis following five successive steps: (1) quantifying biophysical and economic values of ESs using three valuation approaches; (2) identifying six major driving forces on ESs; (3) categorizing principal data components with dimensionality reduction; (4) constructing multivariate regression models with variance partitioning; (5) implementing six spatial regression models to examine the causal effects of natural and anthropogenic forcings on ESs. Results show that climatic factors, biophysical factors, and environmental stressors significantly affect the ESs. Among the six driving factors, climate factors are highly associated with the ESs variation and explain the maximum model variances (R2 = 0.75–0.81). Socioeconomic (R2 = 0.44–0.66) and development (R2 = 27–0.44) factors have weak to moderate effects on the ESs. Furthermore, the joint effects of the driving factors are much higher than their individual effects. Among the six spatial regression models, Geographical Weighted Regression (GWR) performs the most accurately and explains the maximum model variances. The proposed hybrid valuation method aggregates biophysical and economic estimates of ESs and addresses methodological biases existing in the valuation process. The presented framework can be generalized and applied to other ecosystems at different scales. The outcome of this study could be a reference for decision-makers, planners, land administrators in formulating a suitable action plan and adopting relevant management practices to improve the overall socio-ecological status of the region.

In bare soils of semi-arid areas, surface crusting is a rather common phenomenon due to the impact of raindrops. Water infiltration measurements under ponding conditions constitute a common way for an approximate characterization of crusted soils. In this study, the impact of crusting on soil hydraulic conductivity was assessed in a Mediterranean vineyard (western Sicily, Italy) under conventional tillage. The BEST (Beerkan Estimation of Soil Transfer parameters) algorithm was applied to the infiltration data to obtain the hydraulic conductivity of crusted and uncrusted soils. Soil hydraulic conductivity was found to vary during the year and also spatially (i.e., rows vs. inter-rows) due to crusting, tillage and vegetation cover. A 55 mm rainfall event resulted in a decrease of the saturated soil hydraulic conductivity, Ks, by a factor close to two in the inter-row areas, due to the formation of a crusted layer at the surface. The same rainfall event did not determine a Ks reduction in the row areas (i.e., Ks reduced by a non-significant factor of 1.05) because the vegetation cover intercepted the raindrops and therefore prevented alteration of the soil surface. The developed ring insertion methodology on crusted soil, implying pre-moistening through the periphery of the sampled surface, together with the very small insertion depth of the ring (0.01 m) prevented visible fractures. Consequently, beerkan tests carried out along and between the vine-rows and data analysis by the BEST algorithm allowed to assess crusting-dependent reductions in hydraulic conductivity with extemporaneous measurements alone. Testing the beerkan infiltration run in other crusted soils and establishing comparisons with other experimental methodologies appear advisable to increase confidence on the reliability of the method, that seems suitable to allow simple characterization of crusted soils.

Ecosystem Services (ESs) are the direct and indirect benefits and opportunities that human obtained from the ecosystem. This study evaluated landscape capacity of providing multiple key ESs in a tropical coastal ecosystem (Sundarbans Biodiversity Region (SBR)India). Multiple supervised machine learning algorithms were utilized to classify the regions into several landscape zones. The provisioning capacities of ESs for each landscape type were derived separately from an expert opinion survey and the remote sensing based methods, and the association of the outcomes between these two approaches was evaluated using the Pearson correlation coefficient test. A total of nine ESs were selected to quantify their economic values for several reference years. The benefit transfer and equivalent value coefficient approaches were used to aggregate the economic values for each ES. Research results indicated that the water bodies are the most important landscape units in the SBR region. This ecosystem has the highest relevant capacity to provide the necessary regulatory, supporting, provisioning, and cultural ESs. Water regulation (WR), waste treatment (WT), aesthetic, recreation, and cultural (ARC), and climate regulation (CR) are the main ESs of the SBR. These services are immensely important not only for upgrading the livelihood status of coastal communities but also for the climatic and environmental suitability of the Kolkata urban region. The correlation results between the remote sensing and expert-based capacity estimates have suggested that the proposed remote sensing approach could be an alternative to evaluate the landscape capacity of providing multiple ESs in any given ecosystem. Except for the mangrove region, a very high (>0.7) correlation was observed between the model and expert-derived capacity values. The outcome of this study could be an important reference to the land administrators, planners, decision makers for adopting suitable land resource management plans for sustainable uses of natural resources in coastal region.

Gully erosion is one of the most effective drivers of sediment removal and runoff from highland areas to valley floors and stable channels, where continued off-site effects of water erosion occur. Gully initiation and development is a natural process that greatly impacts natural resources, agricultural activities, and environmental quality as it promotes land and water degradation, ecosystem disruption, and intensification of hazards. In this research, an attempt is made to produce gully erosion susceptibility maps for the management of hazard-prone areas in the Pathro River Basin of India using four well-known machine learning models, namely, multivariate additive regression splines (MARS), flexible discriminant analysis (FDA), random forest (RF), and support vector machine (SVM). To support this effort, observations from 174 gully erosion sites were made using field surveys. Of the 174 observations, 70% were randomly split into a training data set to build susceptibility models and the remaining 30% were used to validate the newly built models. Twelve gully erosion conditioning factors were assessed to find the areas most susceptible to gully erosion. The predisposing factors were slope gradient, altitude, plan curvature, slope aspect, land use, slope length (LS), topographical wetness index (TWI), drainage density, soil type, distance from the river, distance from the lineament, and distance from the road. Finally, the results from the four applied models were validated with the help of ROC (Receiver Operating Characteristics) curves. The AUC value for the RF model was calculated to be 96.2%, whereas for those for the FDA, MARS, and SVM models were 84.2%, 91.4%, and 88.3%, respectively. The AUC results indicated that the random forest model had the highest prediction accuracy, followed by the MARS, SVM, and FDA models. However, it could be concluded that all the machine learning models performed well according to their prediction accuracy. The produced GESMs can be very useful for land managers and policy makers as they can be used to initiate remedial measures and erosion hazard mitigation in prioritized areas.

Soil surface sealing is a major cause of decreased infiltration rates and increased surface runoff and erosion during a rainstorm. The objective of this paper is to quantify the effect of surface sealing on infiltration for 3 layered soils with different textures for the upper layer and investigate the capability of BEST procedure to catch the formation of the seal and related consequences on water infiltration. Rainfall experiments were carried out to induce the formation of the seal. Meanwhile, Beerkan infiltration runs were carried out pouring water at different distances from the soil surface (BEST-H versus BEST-L runs, with a High and Low water pouring heights, respectively) for the same type of layered soils. Then, we determined saturated soil hydraulic conductivity, Ks, values from rainfall simulation and Beerkan infiltration experiments. Rainfall simulations carried out on soil layers having different depths allowed to demonstrate that infiltration processes were mainly driven by the seal and that Ks estimates were representative of the seal. Mean Ks values, estimated for the late-phase, ranged from 13.9 to 26.2 mm h−1. Soil sealing induced an increase in soil bulk density by 38.7 to 42.1%, depending on the type of soil. Rainfall-deduced Ks data were used as target values and compared with those estimated by the Beerkan runs. BEST-H runs proved more appropriate than BEST-L runs, those last triggering no seal formation. The predictive potential of the three BEST algorithms (BEST-slope, BEST-intercept and BEST-steady) to yield a proper Ks estimate for the seal was also investigated. BEST-slope yielded negative Ks values in 87% of the cases for BEST-H runs. Positive values were obtained in 100% of the cases with BEST-steady and BEST-intercept. However, poorer fits were obtained with the latter algorithm. The comparison of Ks estimates with rainfall-deduced estimates allowed to identify BEST-steady algorithm with BEST-H run as the best combination. The method proposed in this study could be used to easily measure the seal's saturated hydraulic conductivity of an initially undisturbed bare soil directly impacted by water with minimal experimental efforts, using small volumes of water and easily transportable equipment.

It is of fundamental importance to model the relationship between geo-environmental factors and piping erosion because of the environmental degradation attributed to soil loss. Methods that identify areas prone to piping erosion at the regional scale are limited. The main objective of this research is to develop a novel modeling approach by using three machine learning algorithms-mixture discriminant analysis (MDA), flexible discriminant analysis (FDA), and support vector machine (SVM) in addition to an unmanned aerial vehicle (UAV) images to map susceptibility to piping erosion in the loess-covered hilly region of Golestan Province, Northeast Iran. In this research, we have used 22 geo-environmental indices/factors and 345 identified pipes as predictors and dependent variables. The piping susceptibility maps were assessed by the area under the ROC curve (AUC). Validation of the results showed that the AUC for the three mentioned algorithms varied from 90.32% to 92.45%. We concluded that the proposed approach could efficiently produce a piping susceptibility map.

This study aimed at determining the field-saturated soil hydraulic conductivity, Kfs, of an unmanaged field affected by fire by means of single-ring infiltrometer runs and the use of transient and steady-state data analysis procedures. Sampling and measurements were carried out in 2012 and 2017 in a fire-affected field (burnt site) and in a neighboring non-affected site (control site). The predictive potential of different data analysis procedures (i.e., transient and steady-state) to yield proper Kfs estimates was investigated. In particular, the transient WU1 method and the BB, WU2 and OPD methods were compared. The cumulative linearization (CL) method was used to apply the WU1 method. Values of Kfs ranging from 0.87 to 4.21 mm·h−1 were obtained, depending on the considered data analysis method. The WU1 method did not yield significantly different Kfs estimates between the sampled sites throughout the five-year period, due to the generally poor performance of the CL method, which spoiled the soil hydraulic characterization. In particular, good fits were only obtained in 23% of the cases. The BB, WU2 and the OPD methods, with a characterization based exclusively on a stabilized infiltration process, yielded an appreciably lower variability of the Kfs data as compared with the WU1 method. It was concluded that steady-state methods were more appropriate for detecting slight changes of Kfs in post-fire soil hydraulic characterizations. Our results showed a certain degree of soil degradation at the burnt site with an immediate reduction of the soil organic matter and a progressive increase of the soil bulk density during the five years following the fire. This general impoverishment resulted in a slight but significant decrease in the field-saturated soil hydraulic conductivity.

In recent years, parallel developments in disparate disciplines have focused on what has come to be termed connectivity; a concept used in understanding and describing complex systems. Conceptualisations and operationalisations of connectivity have evolved largely within their disciplinary boundaries, yet similarities in this concept and its application among disciplines are evident. However, any implementation of the concept of connectivity carries with it both ontological and epistemological constraints, which leads us to ask if there is one type or set of approach(es) to connectivity that might be applied to all disciplines. In this review we explore four ontological and epistemological challenges in using connectivity to understand complex systems from the standpoint of widely different disciplines. These are: (i) defining the fundamental unit for the study of connectivity; (ii) separating structural connectivity from functional connectivity; (iii) understanding emergent behaviour; and (iv) measuring connectivity. We draw upon discipline-specific insights from Computational Neuroscience, Ecology, Geomorphology, Neuroscience, Social Network Science and Systems Biology to explore the use of connectivity among these disciplines. We evaluate how a connectivity-based approach has generated new understanding of structural-functional relationships that characterise complex systems and propose a ‘common toolbox’ underpinned by network-based approaches that can advance connectivity studies by overcoming existing constraints.

The WUR Unmanned Aerial Remote Sensing Facility (UARSF) (www.wageningenur.nl/uarsf ) is a co-operation organization of different groups within Wageningen University and Research Centre to use UAVs in remote sensing applications. The facility was founded in 2012. Since then the facility has taken part in numerous of mapping campaigns exploiting UAVs with researchers with in WUR as well as external cooperating partners. In this paper/poster we present the facility, the UAV platforms, the camera systems, and demonstrate some highlights of our results.

Soil erosion in vineyards is considered as an environmental concern as it depletes soil fertility and causes damage in the fields and downstream. High soil and water losses decrease soil quality, and subsequently, this can reduce the quality of the grapes and wine. However, in specialized journals of viticulture and enology, soil erosion studies are not present. This paper surveys the soil erosion losses in the vineyards of Celler del Roure, Eastern Spain, as an example of Mediterranean vineyards. We applied rainfall simulation experiments (10 plots) using a small portable rainfall simulator and 55 mm h−1 in one hour to characterize soil erodibility, runoff discharge, and soil erosion rates under low-frequency–high-magnitude rainfall events at different positions along the vine inter-row areas. We found that 30% of the rainfall was transformed into superficial runoff, the sediment concentration was 23 g L−1, and the soil erosion rates reached 4.1 Mg ha−1 h−1; these erosion rates are among the highest found in the existing literature. We suggest that the vineyard management should be improved to reduce land degradation, and also should be shifted to sustainable agricultural production, which could improve grape and wine quality.

[EN] It is needed to find the proper management from a biophysical point of view to promote sustainable agriculture. However, it is also necessary that farmers accept new strategies that propose cultural and technical shifts. A survey of the fannerg perception, and an assessment of the biophysical impact of catch crops (CC) and weeds (W) on soil organic matter, bulk density, infiltration capacity, runoff initiation, runoff discharge and soil detachment at the pedon scale were carried out. The field measurements in the Alcoleja experimental station demonstrated that organic matter and bulk density after 10 years of Vicla saliva L and Avena saliva L catch crops and weeds managed plots are similar. Both CC and W plots enhanced high infiltration rates under single ring ponding conditions, the runoff discharge was delayed and decreased; and soil erosion rates were lower in comparison to soil erosion rates measured in chemically managed farms. Soil quality was high for both management strategies and soil erosion rates much sustainable due to the live mulch that catch crops and weeds developed. However, an assessment of the farmed perception in the Canyoles river watershed citrus production area in Eastern Spain demonstrated that the farmer's community did not accept the use of catch crops or weeds. The survey proved that the farmers would accept the use of CC and W if subsidies were paid. The farmers claimed for the payment of the seeds and sowing expenses plus a 57 (sic) ha(-1) for the CC and 75 (sic) ha(-1) for Won average. The farmers considered the use of CC and W as benefit for the society, but not for them., This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4, http://recare-project.eu). We thank the editors and reviewers for their improvements to and careful review of the paper. The second coauthor, J. Rodrigo-Comino, was issued a grant to complete this study and some other about vineyards under the framework of a short-term scientific mission (COST-STSM-ECOST-STSM-ES1306-010217-081877).

Land Degradation Neutrality (LDN) is a key voluntary and aspirational target of Sustainable Development Goal (SDG) 15 which urges countries to protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss. A first and critical important step in the implementation of LDN is assessing the current land condition using not only active restoration of degraded land, but also targeting land degradation drivers behind the land degradation process. In a first step to achieve these goals, countries were provided a global dataset for three sub-indicators of land degradation: land cover (LC), land productivity dynamics (LPD) and soil organic carbon (SOC). Here, we report on trends in these sub-indicators for the Entity Republic of Srpska (RS) as a part of Bosnia and Herzegovina, which is a key analysis to inform the frame of reference or baseline conditions for the region to evaluate LDN across this region. Global data for LC for the RS indicates a 0.5% loss of forests (6400 ha) over the time period from 2000 to 2010. Of this area, 5000 ha were converted to cropland and an additional 1400 ha was converted to shrubs, grasslands and sparsely vegetated areas. LPD declined over 2.5% (63,500 ha) of the region. SOC declined on land use changed areas by 15.6% (74,609 Mg ha−1) over the same time period. Based on global data, we estimated that 3% of the country is in a degraded state. Based on interviews with local stakeholders in 31 local communities, the primary land degradation drivers were identified and validated by team experts. Depopulation and migration to urban centers were identified as the important underlying drivers of land degradation that most municipalities are facing. The most frequent direct drivers of land degradation across this region were land abandonment, floods, drought, erosion and urbanization. Land abandonment, more specifically, has resulted in conversion of agriculturally productive lands to lands dominated by a wide range of invasive species over the last 25 years. Continued land degradation is underpinned by the lack of understanding by stakeholders of the importance of land as a resource. In evaluating the status, trends and drivers of land degradation for this region, we have identified key areas or "hot spots" that may be targeted for restoration options and may be used to achieve LDN targets by 2030.

All rights reserved. Vineyards have proven to be one of the most degraded agricultural ecosystems due to very high erosion rates, which are typically measured at fine temporal and spatial scales. Long-term soil erosion measures are rare, but this information may be indispensable for a proper understanding of the vineyard soil system, landscape evolution, and crop production. The stock unearthing method (SUM) is a common topographical measurement technique developed to assess long-term erosion rates. The reliance of the SUM has been questioned and should be replaced by an improved measurement technique. In this paper, we demonstrate the added value (improved accurate, low cost, and faster than photogrammetrically methods) of the improved stock unearthing method (ISUM). It was shown that large errors may have been made in previous assessments of soil erosion on vineyards, as the old method did not make measurements in the inter-row area or consider the timing of the erosion assessment in relation to tillage events. We found that this caused the SUM to severely underestimate soil erosion rates by –14.2 and –37.8% in 1- and 86-d tillage vineyards in one location, respectively. Furthermore, the increased measurement resolution attained from the ISUM allowed for the detailed assessment of micro-topographical change. Soil loss maps were able to detect the locational ch anges in soil depletion and accumulation, as well as continuous soil movement features in the inter-row areas. Ultimately, this leads to a more accurate estimate of the actual soil erosion rates in vineyards.

International audience; Using concepts of connectivity in challenges regarding land and water management (flooding, erosion, nutrient leaching, landslides) can only be fully harnessed if knowledge is communicated well between scientists and stakeholders. Proper communication requires prior understanding of end-users' perception of connectivity as a useful framework. Therefore, we analysed (a) perceptions of connectivity' for stakeholders involved in water and land management across Europe, (b) potential for stakeholders to apply connectivity-related measures in their management decisions, (c) stakeholders' biggest challenges in water and land management, and (d) stakeholders' expectations for future connectivity research agendas. We studied 85 questionnaires from 19 countries using a grounded theory approach. One third of stakeholders understood connectivity in its scientific context, whereas 39% perceived connectivity indirectly through their personal experiences (e.g., water and sediment fluxes and erosion). Half of stakeholders' perceived links and challenges were related to availability of data and methods, communication, and institutions or policy, whereas others believed they were related to water quality and quantity, soil erosion and quality, and climate change. Half of the stakeholders considered connectivity management important, and one third showed high interest in managing connectivity. Adopting connectivity into management is hindered by institutional- and policy-based management limitations, insufficient data and methods, and ineffective knowledge transfer. Explicitly considering heterogeneity of stakeholder perceptions is required for projects regarding management of connectivity at European, national, and local scales.

[EN] There is a need to devise management strategies that control soil and water losses in agriculture land to allow the design of proper policies to achieve sustainability. It is the responsibility of scientists to work with other actors to co-construct strategies that will lead to sustainable land-use policies. Using chipped pruned branches (CPB) as mulch can be a viable option because they represent local (in situ) organic material that can restore soil nutrient and organic matter. This research assesses: i) the perception of farmers towards different types of management strategies and CPB's costs; ii) the biomass yield of citrus branches and the impact of CPB on soil properties; iii) how CPB affects soil erosion and runoff generation in citrus plantations; and, iv) a discussion about how to favour the use of CPB thought successful policies. To achieve those goals we carried out: i) one-hundred it interviews to assess the perception of farmers and twelve interviews to assess the economic balance of twelve land owners; ii) soil was sampled at 0-2 and 4-6 cm depths; iii) pruned material was surveyed for 40 trees; and iv) forty rainfall simulation experiments (55 mm h(-1)) were carried out in two citrus plantations at paired sites (Control versus CPB), in La Costera District in Eastern Spain. Forty circular (0.25 m(2)) plots were installed in focus rows (4 x 5 = 20 plots) in control (CON) and CPB plots (20 + 20 = 40 plots) to perform the rainfall simulation over one hour. The cost of chipping ranged from 102 to 253 epsilon ha(-1), and was related to the size of the farm. soil quality, runoff and erosion assessment showed that CPB is a suitable strategy. CPB increased organic matter from 1.3% to 2.9% after 10 years in the 0-2 cm depth layer, while the 4-6 cm layer was largely not affected (OM moved from 1.1 to 1.3% after 10 years), and soil bulk density showed a similar trend: a decrease from 1.36 to 1.16 g cm(-3) in the surface layer with no change in the subsurface layer. The hydrological and erosional responses were different between CON and CPB. The CON plots initiated ponding (40 s) and runoff (107 s) earlier than the CPB plots (169 and 254 s, respectively); and runoff discharge was 60% in CON vs 43% in CPB plots Sediment concentration was four times larger in the CON plots than in the CPB (11.3 g l(-1) vs 3 g l(-1)), and soli erosion was 3.8 Mg ha(-1) h(-1) vs 0.7 Mg ha(-1) h(-1). CPB mulches were effective at controlling soil and water losses in Mediterranean citrus plantations as they showed the relationship between vegetation/litter cover and soli erosion rates. However, the farmer's perception survey showed that the use of CPB was not welcomed nor accepted by the farmers. Policies that aim to promote CPB as soil conservation mulch need to by promoted subsidies as the farmers requested, and by education to demonstrate the positive effects of CPB to of the farming community., This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4, http://recare-project.eu).

Agricultural productivity in rural areas is severely affected by climate variability, and this elevates the vulnerability of rural households to food insecurity. This study examines the socio-economic vulnerability of farmers who are susceptible to droughts in the five agricultural-based regions of Gadaref, Eastern Sudan. A survey was carried out in 500 households to collect data on socio-economic and livelihood indicators. The data analyzed from these indicators were used to generate the three components of drought vulnerability: exposure, sensitivity and adaptive capacity. The analysis revealed that the regions deemed to be most vulnerable to both drought and climate variability were also projected to have the most vulnerable communities. The most exposed farming communities of Alfaw, Algadaref and Alfushqa regions showed a relatively low capacity for adaptation. Moreover, the study determined that vulnerability to drought and variability is associated with social and economic development in the Gadaref region. The results show that highly vulnerable regions are characterized by features such as low levels of productivity, elevated levels of financing, low crop diversity, agriculture as the primary income source and a low level of agricultural insurance. This research shows the importance of diversified livelihoods in building resilience against hazards linked to climate change.

In the effort to achieve the Sustainable Development Goals (SDGs) related to food, health, water, and climate, an increase in pressure on land is highly likely. To avoid further land degradation and promote land restoration, multifunctional use of land is needed within the boundaries of the soil-water system. In addition, awareness-raising, a change in stakeholders&rsquo, attitudes, and a change in economics are essential. The attainment of a balance between the economy, society, and the biosphere calls for a holistic approach. In this paper, we introduce four concepts that we consider to be conducive to realizing LDN in a more integrated way: systems thinking, connectivity, nature-based solutions, and regenerative economics. We illustrate the application of these concepts through three examples in agricultural settings. Systems thinking lies at the base of the three others, stressing feedback loops but also delayed responses. Their simultaneous use will result in more robust solutions, which are sustainable from an environmental, societal, and economic point of view. Solutions also need to take into account the level of scale (global, national, regional, local), stakeholders&rsquo, interests and culture, and the availability and boundaries of financial and natural capital. Furthermore, sustainable solutions need to embed short-term management in long-term landscape planning. In conclusion, paradigm shifts are needed. First, it is necessary to move from excessive exploitation in combination with environmental protection, to sustainable use and management of the soil-water system. To accomplish this, new business models in robust economic systems are needed based on environmental systems thinking, an approach that integrates environmental, social, and economic interests. Second, it is necessary to shift from a &ldquo, system follows function&rdquo, approach towards a &ldquo, function follows system&rdquo, one. Only by making the transition towards integrated solutions based on a socio-economical-ecological systems analysis, using concepts such as nature-based solutions, do we stand a chance to achieve Land Degradation Neutrality by 2030. To make these paradigm shifts, awareness-raising in relation to a different type of governance, economy and landscape and land-use planning and management is needed.

An extreme flood occurred on 14 April 2016 in the Karoon River, Iran. The occurred flood discharge was the highest discharge recorded over the last 60 years in the Karoon River. Using the OLI Landsat images taken on 8 April 2016 (before the flood) and 24 April 2016 (after the flood) the geomorphic effects were detected in different land cover types within the 155-km-long study reach. The results show that the flood significantly affected the channel width and the main effect was high mobilization of channel sediments and severe bank erosion in the meandering reaches. According to field surveys, the flood occupied the channel corridor and even the floodplain parts. However, the channel pattern was not significantly altered, although the results show that the average channel width increased from 192 to 256 m. Statistical results indicate a significant change for active channel width and sinuosity index at 99% confidence level for both indexes. The flood-induced morphological changes varied significantly for different land cover types along the Karoon River. Specifically, the channel has widened less in residential areas than in other land cover types because of the occurrence of bank protection structures. However, the value of bank retreat in residential and protected sides of the Karoon River is more than what we expected during the study of extreme flood.

Agriculture has a large effect on the properties of the soil and with that on soil hydrology. The partitioning of rainfall into infiltration and runoff is relevant to understand runoff generation, infiltration and soil erosion. Tillage manages soil surface properties and generates soil surface roughness (SSR) that affects the partitioning of the rainfall. The objective of this study was to quantify the amount of rainwater that infiltrates, is temporarily stored in surface depressions and flows out of the surfaces during rainfall events. A set of tillage-induced rough surfaces with slope steepness of 10° and 15° was used under simulated rainfall, and a smooth surface served as a control. Rainfall intensities were 60 and 120 mm h−1, and two soil erosion periods, overland flow erosion period (OFEP) and rill flow erosion period (RFEP), were monitored for each rainfall intensity. The results showed that for OFEP, infiltration water was 58% and 76% of the total rainwater on the rough surfaces and was approximately 1.5 and 2 times greater than that on the smooth surfaces for the different rainfall intensities. The surface runoff was consistently small for the OFEP but significantly increased for the RFEP. For example, for the RFEP, the amount of surface runoff was up to 78.66% of the total rainwater on the rough surfaces under rainfall of 120 mm h−1 in intensity. The amount of rainwater stored in surface depressions was significantly less than infiltration water and surface runoff for all conditions. The mean transformation ratio of rainwater into surface depression storage, infiltration water and surface runoff in the OFEP and RFEP was 0.07:0.49:0.44 for the rough surfaces and 0.01:0.29:0.70 for the smooth surfaces. For the tilled surfaces, more than 50% of rainwater was be harvested through tillage technique during a rainfall event, whereas for the smooth surfaces, only 29% of rainwater. Our result will be useful when evaluating the impact of tillage on soil moisture content and even studying soil erosion in agriculture land.

[EN] Land abandonment is widespread in the Mediterranean mountains. The impact of agricultural abandonment results in a shift in ecosystem evolution due to changes in soil erosion, but little is known about long-term soil and water losses. This paper uses 11 years of measurements in two paired plots (abandoned vs control) with four subplots to determine how soil and water losses evolved after abandonment within an agricultural parcel. For two years (2004¿2005) both plots were under tillage, and after 2006 one plot was abandoned. The monitored plots measured runoff and sediment concentration after each rainfall event., The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 603498 (RECARE project), POST-FIRE Project (CGL2013-47862-C2-1 and 2-R) and POSTFIRE_CARE Project (CGL2016-75178-C2-2-R) sponsored by the Spanish Ministry of Economy and Competitiveness.

Explaining scale effects for runoff and erosion improves our understanding and simulation ability of hydrological and erosion processes. In this paper, plot scale effects on event runoff per unit area (Qe), sediment concentration (Ce) and soil loss per unit area (SLe) were checked at El Teularet-Sierra de Enguera experimental site in Eastern Spain. The measurements were carried out for 31 events occurring in the years 2005 and 2007 in bare ploughed plots ranging from 1 to 48 m2. The analysis established the scaling relationship by dimensional analysis and self-similarity theory, and tested this relationship at different temporal scales ranging from event to annual scale. The dimensional analysis and the incomplete self-similarity condition allowed us to establish a power scaling relationship which was found to also be usable for the moments of k (1, 2, 3, 4) order. The power scaling relationship was theoretically deduced applying a boundary condition which is based on the hypothesis that sediment delivery processes do not occur at the selected plot scale. The simple scaling invariance condition was always verified (i.e. for each temporal horizon) for runoff and soil loss while the same hypothesis was not perfectly acceptable for sediment concentration. The analysis of the scaling relationships at event temporal scale showed that the spatial scale effects were less frequent for the composite variable (soil loss = sediment concentration × runoff) than the constituting variables. For 48% of the events, a statistically significant scale effect was detected for all tested variables. With reference to the statistically significant relationships, both runoff and soil loss always decreased and sediment concentration always increased in the passage from the reference area (1 m2) to the largest one (48 m2). The analysis at aggregated temporal scales suggested that annual scale effects for soil loss per unit area should be temporally more stable than those for both runoff and sediment concentration. Finally, at mean event scale the three investigated variables have a similar behaviour in terms of simple scaling invariance.

This study quantifies morphological evolution of the Dez River, Iran, from 1955 to 2016. The approach uses a sequence of Landsat images, aerial photos, and topographic maps. In addition, the hydrological data including average daily discharge and yearly maximum discharge at the Dezful hydrological station for the period (1955–2016) were used. The study reach was divided into 48 meander loops from upstream to downstream. Active channel width (w) was determined at 10 m intervals and changes assessed along the study reach of the Dez River. Morphological indices including sinuosity index; straight meander length; centerline flow length; erosion area; erodible length channel migration; centerline elongation; and radius of curvature were calculated in the reach. Results showed that the study reach of the Dez River changed dramatically in response to major floods, although the general trend is towards a narrowing of active channel width by 38% in the period 1955–2016. Results show that most of the meander loops in the study area extended and expanded. Between 1989 and 1995, all types of meander change were observed. There was a direct correlation between the frequency of hydrological events (flood days) bigger than 2-years return period and elongation of bends.

Evaluating the lateral saturated hydraulic conductivity, Ks,l, of soil horizons is crucial for understanding and modelling the subsurface flow dynamics in many shallow hill soils. A Ks,l measurement method should be able to catch the effects of soil heterogeneities governing hydrological processes at the scale of interest, in order to yield Ks,l representative values over large spatial scales. This study aims to develop a field technique to determine spatially representative Ks,l values of soil horizons of an experimental hillslope. Drainage experiments were performed on soil monoliths of about 0.12 m3 volume, encased in situ with polyurethane foam. Median Ks,l of 2450 mm·h-1 and 552 mm·h-1 were estimated in the A and B horizon, respectively. In the upper part of the B horizon, the median Ks,l was 490 mm·h-1, whereas it mostly halved near the underlying restricting layer. The decline of Ks,l values with depth was consistent with the water-table dynamics observed at the same site in previous studies. Moreover, the Ks,l from the monoliths were in line with large spatial-scale Ks,l values reported from the hillslope in a prior investigation based on drain data analysis. This indicated that the large-scale hydrological effects of the macropore network were well represented in the investigated soil blocks. Our findings suggest that performing drainage experiments on large-volume monoliths is a promising method for characterizing lateral conductivities over large spatial scales. This information could improve our understanding of hydrological processes and can be used to parameterize runoff-generation models at hillslope and catchment scale.

This paper considers legacy data and data rescue within the context of geomorphology. Data rescue may be necessary dependent upon the storage medium (is it physically accessible) and the data format (e.g. digital file type); where either of these is not functional, intervention will be required in order to retrieve the stored data. Within geomorphological research, there are three scenarios that may utilize legacy data: to reinvestigate phenomena, to access information about a landform/process that no longer exists, and to investigate temporal change. Here, we present three case studies with discussion that illustrate these scenarios: striae records of Ireland were used to produce a palaeoglacial reconstruction, geomorphological mapping was used to compile a map of glacial landforms, and aerial photographs were used to analyze temporal change in river channel form and catchment land cover.

Reservoir and lake sedimentation is a vital problem in Ethiopia. Constructing small and medium size dams at the outlets of sub-catchments within a larger catchment helps to reduce the transport of sediment downstream to reservoirs or lakes. This study assessed the sediment trapping efficacy (STE) of sediment storage dams (SSDs) built at the outlets of eight small sub-catchments in northwest Ethiopia, as an off-site sediment trapping measure. Satellite imagery and topographic maps were used to assess land use-land cover and delineate the boundaries of sub-catchments. In the field, trapped sediment by SSDs was measured directly, as well as in- and outflow of suspended sediment with which the STE of each SSD was estimated. Sediment yield of each sub-catchment was calculated from the measured trapped sediment and estimated suspended sediment loss. Results show that SSDs trapped an average of 1584 t yr -1 of the inflow sediment and catchment specific sediment yield ranged from 8.6-55 t ha -1 yr -1 . Two representative SSDs constructed from gabion and stone were evaluated with regard to their STE. Results showed that their efficacy was 74% and 67% for the gabion and stone SSD, respectively. In general, although SSDs might be costly for small scale farmers and have a relatively short life span depending on their size, they are promising off-site structural measures to trap significant amounts of sediment at the outlets of sub-catchments and subsequently reduce sediment movement to downstream water bodies. Evaluacion de presas de retencion de sedimento: medidas estructurales de control del transporte de sedimento en el noroeste de Etiopia

The set-up and characterisation of an indoor nozzle-type rainfall simulator (RS) at Wageningen University, the Netherlands, are presented. It is equipped with four Lechler nozzles (two nr. 460·788 and two nr. 461·008). The tilting irrigation plot is 6 m long and 2·5 m wide. An electrical pump supplies the constant flow during the experiments. The spatial distribution of the rainfall was measured with 60 rain gauges equally distributed on the experimental plot. Thies® Laser Precipitation Monitor was used to measure the size and falling velocity of the raindrops. Four different flow rates were applied (Q1–4). From the collected data, spatial rainfall intensity and spatial kinetic energy distribution maps were created; Christiansen uniformity coefficient was calculated for each flow rate. The results of the experiments revealed that the rainfall parameters (spatial rainfall intensity, kinetic energy, raindrop size distribution and fall velocity) in the RS are not homogeneous (Christiansen uniformity ranges from 68·5% to 83·2%). Accordingly, the whole plot can only be irrigated irregularly applying a wide range of intensities and rainfall energies. The RS offers a good opportunity to study great variety of process intensities such as splash erosion, runoff generation, soil aggregate stability, organic matter migration and scaled landscape development.

In the present study, we investigate the effects of urbanization growth on river morphology in the downstream part of Talar River, east of Mazandaran Province, Iran. Morphological and morphometric parameters in 10 equal sub-reaches were defined along a 11.5 km reach of the Talar River after land cover maps were produced for 1955, 1968, 1994, 2005 and 2013. Land cover types changed extremely during the study period. Residential lands were found to have increased in area by about 1631%, while forest land and riparian vegetation decreased in by approximately 99.9 and 96.2%, respectively. The results of morphometric and morphological factors showed that average channel width (W) for all 11.5 km of the study river decreased by 84% during the study period, while the flow length increased by about 2.14%.

Flood is one of the most destructive natural disasters which cause great financial and life losses per year. Therefore, producing susceptibility maps for flood management are necessary in order to reduce its harmful effects. The aim of the present study is to map flood hazard over the Jahrom Township in Fars Province using a combination of adaptive neuro-fuzzy inference systems (ANFIS) with different metaheuristics algorithms such as ant colony optimization (ACO), genetic algorithm (GA), and particle swarm optimization (PSO) and comparing their accuracy. A total number of 53 flood locations areas were identified, 35 locations of which were randomly selected in order to model flood susceptibility and the remaining 16 locations were used to validate the models. Learning vector quantization (LVQ), as one of the supervised neural network methods, was employed in order to estimate factors' importance. Nine flood conditioning factors namely: slope degree, plan curvature, altitude, topographic wetness index (TWI), stream power index (SPI), distance from river, land use/land cover, rainfall, and lithology were selected and the corresponding maps were prepared in ArcGIS. The frequency ratio (FR) model was used to assign weights to each class within particular controlling factor, then the weights was transferred into MATLAB software for further analyses and to combine with metaheuristic models. The ANFIS-PSO was found to be the most practical model in term of producing the highly focused flood susceptibility map with lesser spatial distribution related to highly susceptible classes. The chi-square result attests the same, where the ANFIS-PSO had the highest spatial differentiation within flood susceptibility classes over the study area. The area under the curve (AUC) obtained from ROC curve indicated the accuracy of 91.4%, 91.8%, 92.6% and 94.5% for the respective models of FR, ANFIS-ACO, ANFIS-GA, and ANFIS-PSO ensembles. So, the ensemble of ANFIS-PSO was introduced as the premier model in the study area. Furthermore, LVQ results revealed that slope degree, rainfall, and altitude were the most effective factors. As regards the premier model, a total area of 44.74% was recognized as highly susceptible to flooding. The results of this study can be used as a platform for better land use planning in order to manage the highly susceptible zones to flooding and reduce the anticipated losses.

[EN] Rainfall-induced soil erosion is a major threat, especially in agricultural soils. In the Mediterranean belt, vineyards are affected by high soil loss rates, leading to land degradation. Plantation of new vines is carried out after deep ploughing, use of heavy machinery, wheel traffic, and trampling. Those works result in soil physical properties changes and contribute to enhanced runoff rates and increased soil erosion rates. The objective of this paper is to assess the impact of the plantation of vineyards on soil hydrological and erosional response under low frequency - high magnitude rainfall events, the ones that under the Mediterranean climatic conditions trigger extreme soil erosion rates. We determined time to ponding, Tp; time to runoff, Tr; time to runoff outlet, Tro; runoff rate, and soil loss under simulated rainfall (55 mm h(-1), 1 h) at plot scale (0.25 m(2)) to characterize the runoff initiation and sediment detachment. In recent vine plantations (50 years; O). Slope gradient, rock fragment cover, soil surface roughness, bulk density, soil organic matter content, soil water content and plant cover were determined. Plantation of new vineyards largely impacted runoff rates and soil erosion risk at plot scale in the short term. Tp, Tr and Tro were much shorter in R plots. Tr-Tp and Tro-Tr periods were used as connectivity indexes of water flow, and decreased to 77.5 and 33.2% in R plots compared to O plots. Runoff coefficients increased significantly from O (42.94%) to R plots (71.92%) and soil losses were approximately one order of magnitude lower (1.8 and 12.6 Mg ha(-1) h(-1) for O and R plots respectively). Soil surface roughness and bulk density are two key factors that determine the increase in connectivity of flows and sediments in recently planted vineyards. Our results confirm that plantation of new vineyards strongly contributes to runoff initiation and sediment detachment, and those findings confirms that soil erosion control strategies should be applied immediately after or during the plantation of vines. (C) 2017 Elsevier Ltd. All rights reserved., This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4, http://recare-project.eu/).

Soil infiltration processes manage runoff generation, which in turn affects soil erosion. There is limited information on infiltration rates. In this study, the impact of vine age on soil bulk density (BD) and hydraulic conductivity (Ks) was assessed on a loam soil tilled by chisel plough. Soil sampling was conducted in the inter row area of six vineyards, which differed by the age from planting: 0 (Age 0; just planted), 1, 3, 6, 13, and 25 years (Age 1, Age 3, Age 6, Age 13, and Age 25, respectively). The One Ponding Depth (OPD) approach was applied to ring infiltration data to estimate soil Ks with an α* parameter equal to 0.012 mm-1. Soil bulk density for Age 0 was about 1.5 times greater than for Age 25, i.e., the long-term managed vineyards. Saturated hydraulic conductivity at Age 0 was 86% less than at Age 25. The planting works were considered a major factor for soil compaction and the reduction of hydraulic conductivity. Compared to the long-term managed vineyards, soil compaction was a very short-term effect given that BD was restored in one year due to ploughing. Reestablishment of Ks to the long-term value required more time.

Human-induced landscape change is difficult to predict due to the complexity inherent in both geomorphic and social systems as well as due to the coupling relationships between them. To better understand system complexity and system response to changing inputs, “connectivity thinking” has become an important recent paradigm within various disciplines including ecology, hydrology and geomorphology. With the presented conceptual connectivity framework on geomorphic change in human-impacted fluvial systems a cautionary note is flagged regarding the need (i) to include and to systematically conceptualise the role of different types of human agency in altering connectivity relationships in geomorphic systems and (ii) to integrate notions of human-environment interactions to connectivity concepts in geomorphology to better explain causes and trajectories of landscape change. Geomorphic response of fluvial systems to human disturbance is shown to be determined by system-specific boundary conditions (incl. system history, related legacy effects and lag times), vegetation dynamics and human-induced functional relationships (i.e. feedback mechanisms) between the different spatial dimensions of connectivity. It is further demonstrated how changes in social systems can trigger a process-response feedback loop between social and geomorphic systems that further governs the trajectory of landscape change in coupled human-geomorphic systems.

[EN] Soil erosion is a key cause of land degradation in agriculture lands; and it is a worldwide threat that must be solved by means of nature-based strategies to be able to achieve sustainability. The use of mulches can be a solution, but there is a lack of information on long-term effects of the use of straw. Furthermore, little is known about the perception of farmers and the economic cost on the implantation of straw as a conservation measure. Eight paired plots were selected in Sierra de Enguera on an agriculture field to determine the effect of straw cover on soil erosion. Four plots were tilled three times per year (Control) and four plots were not ploughed and 0.125 kg m(-2) y(-1) of oat straw cover was applied yearly (Straw). The plots were established in 2002, and runoff and sediment was continuously collected after each rainfall event from 2004 till 2014 when the two managements were applied. The results show an immediate effect of the straw mulches as in these plots the runoff (from 7.7 till 5.9%) and soil erosion (from 47 till 26 Mg ha(-1) y(-1)) was reduced already in the first year. The combined effect of the use of straw yearly and the no-tillage strategy resulted in a reduction of the sediment yield, and 11 years later soil erosion rates were two orders of magnitude lower than in the control plot. However, the perception of the farmers on the use of straw is very negative and they claim that subsidies need to be implemented, as the cost of straw mulch is 1.9 times more expensive than traditional tillage., This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4, http://recare-project.eu).

66 Pags.- 1 Tabl.- 7 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/00128252, Soil erosion is a serious ecological and environmental problem, and the main cause of land degradation in many ecosystems at global scale. Detachment of soil particles by raindrop splash is the first stage in the soil erosion process. A review of the scientific literature published in peer-reviewed international journals (ISI) over the last decades on splash erosion research sheds light on the current scientific knowledge on this topic. In addition, it highlights the research gaps and unanswered questions in our understanding of soil erosion processes due to splash. In this literature review, a bibliographic search in Web of Science by the Institute for Scientific Information (ISI) database was carried out on August the 9th, 2016, that returned 669 papers containing the words “splash erosion”. The research found was categorised according to a number of criteria: i) devices used to measure splash erosion, ii) advantages and disadvantages of these devices, iii) splash erosion studies by country, iv) date of publication of the first article, v) evolution of the number of articles published in each ten-year period, vi) concepts studied, vii) keywords, viii) authors, ix) number of citations, and x) most cited articles. After this review a synthesis of the information that the science has published about splash erosion was made in order to improve our understanding about splash erosion, by identifying the research questions that still remain unanswered today about the first detachment mechanism. From this review several issues were found important for the advancement of this research topic: a) further study of the known basic factors influencing splash erosion; b) description and quantification of sources of uncertainty about the measurement of different variables; c) to understand the influences that the chosen research approach by individual researchers will have in the final result; and, d) to study the impact of drivers or mitigation techniques that may affect splash erosion., This research was funded by the José Castillejo Grant, a Program for Junior professors of the Ministry of Education, Culture and Sports, Spain (CAS16/00385).

Extreme rainfall events have serious implications for economic sectors with a close link to climate such as agriculture and food security. This holds true in the Central Rift Valley (CRV) of Ethiopia where communities rely on highly climate-sensitive rainfed subsistence farming for livelihoods. This study investigates changes in ten extreme rainfall indices over a period of 40 years (1970–2009) using 14 meteorological stations located in the CRV. The CRV consists of three landscape units: the valley floor, the escarpments, and the highlands all of which are considered in our data analysis. The Belg (March–May) and Kiremt (June–September) seasons are also considered in the analysis. The Mann-Kendall test was used to detect trends of the rainfall indices. The results indicated that at the annual time scale, more than half (57 %) of the stations showed significant trends in total wet-day precipitation (PRCPTOT) and heavy precipitation days (R10mm). Only 7–35 % of stations showed significant trends, for the other rainfall indices. Spatially, the valley floor received increasing annual rainfall while the escarpments and the highlands received decreasing annual rainfall over the last 40 years. During Belg, 50 % of the stations showed significant increases in the maximum number of consecutive dry days (CDD) in all parts of the CRV. However, most other rainfall indices during Belg showed no significant changes. During Kiremt, considering both significant and non-significant trends, almost all rainfall indices showed an increasing trend in the valley floor and a decreasing trend in the escarpment and highlands. During Belg and Kiremt, the CDD generally showed increasing tendency in the CRV.

Man-made and natural sediment sinks provide a practical means for reducing downstream reservoir sedimentation by decreasing soil erosion and enhancing the rate of sedimentation within a catchment. The Minizr catchment (20 km2) in the northwest Ethiopian highlands contains numerous man-made soil and water conservation (SWC) structures such as soil bunds (Erken), fanya juu ridge (Cab) and micro-trenches and natural sediment sinks such as wetlands, floodplains and grassed waterways. These sediment sinks reduce downstream sedimentation into the Koga reservoir, located at the catchment outlet, however, a large quantity of sediment is still reaching the reservoir. This study evaluates the function and effectiveness of both man-made SWC structures and natural sediment sinks in reducing sediment export from the Minizr catchment. SWC structures and natural sediment sinks were digitized using Google Earth Imagery. Sediment pins and vertical sampling through the deposit were used to quantify the amount of deposited sediment. In addition, inflow and outflow of suspended sediment data were used to calculate the sediment-trapping efficacies (STE) of man-made SWC structures (soil bunds and fanya juu ridges) and natural sediment sinks. Results reveal that 144 km soil bunds and fanya juu ridges trapped 7,920 Mg y−1 (55 kg m−1 y−1) and micro-trenches trapped 13·26 Mg y−1, each micro-trench on average trapped 23 kg y−1. The 17 ha floodplain located in the centre of the catchment trapped 9,970 Mg y−1 (59 kg m−2 y−1), while a wetland with a surface area of 24 ha, located near the outlet of the catchment, trapped 8,715 Mg y−1 (36 kg m−2 y−1). The STEs of soil bunds and fanya juu ridges, wetlands and floodplains were 54%, 85% and 77%, respectively. Substantial differences were observed between the STE of grassed and un-grassed waterways at 75% and 21%, respectively. Existing man-made and natural sediment sinks played an important role in trapping sediment, with 38% (26,600 Mg y−1) of transported sediment being trapped, while 62% (43,000 Mg y−1) is exported from the catchment and thus enters the Koga reservoir. Therefore, additional catchment treatment measures are required as an integrated catchment scale sediment trapping approach to help reduce sediment loads entering Koga reservoir. Moreover, to maximize the effectiveness of sediment trapping measures, avoid structural failure and ensure their sustainability, regular maintenance is needed.

Soil erosion from agricultural areas is a large problem because of off-site effects like the rapid filling of reservoirs. To mitigate the problem of sediments from agricultural areas reaching the channel, reservoirs and other surface areas it is important to understand hillslope-channel connectivity and catchment connectivity. To determine the functioning of hillslope-channel connectivity and the continuation of transport of these sediments in the channel, it is necessary to obtain data on sediment transport from the hillslopes to the channels. Simultaneously, the factors that influence sediment export out of the catchment need to be studied. For measuring hillslope-channel sediment connectivity, rare-earth oxide (REO) tracers were applied to a hillslope in an agricultural catchment in Navarre, Spain, preceding the winter of 2014-2015. The results showed that during the winter no sediment transport from the hillslope to the channel was detected. To test the implication of the REO results at the catchment scale, two contrasting conceptual models for sediment connectivity were assessed using a random forest (RF) machine learning method. The RF method was applied using a 15-year period of measured sediment output at the catchment scale. One model proposes that small events provide sediment for large events, while the other proposes that only large events cause sediment detachment and small events subsequently remove these sediments from near and in the channel. For sediment yield prediction of small events, variables related to large preceding events were the most important. The model for large events underperformed and, therefore, we could not draw any immediate conclusions whether small events influence the amount of sediment exported during large events. Both REO tracers and RF method showed that low intensity events do not contribute any sediments from the hillslopes to the channel in Latxaga catchment. Sediment dynamics are dominated by sediment mobilization during large (high intensity) events. Sediments are for a large part exported during those events, but the system shows a memory of the occurrence of these large events, suggesting that large amounts of sediments are deposited in and near the channel after these events. These sediments are gradually removed by small events. To better understand the delivery if sediments to the channel and how large and small events influence each other, more field data on hillslope-channel connectivity and within-channel sediment dynamics is necessary. This study was funded by the Dutch Organization for Scientific Research (NWO), grant number 822.01.004, The Spanish Ministry of Science and Innovation, project CGL2015-64284-C2-1-R (MINECO-FEDER) and COST action ES 1306.

Afforestation aims to recover the vegetation cover, and restore natural ecosystems. The plant species selected for restoration will determine species richness and the fate of the ecosystem. Research focussing on the impact of vegetation recovery on soil quality are abundant, especially on fire affected land and where rehabilitation, afforestation and restoration projects were carried out. However, little is known about how different plants species affect soil erosion and water losses, which are key factors that will impact the fate of the afforested land. Aleppo pine (Pinus halepensis M.) is the species commonly used for afforestation in the Mediterranean and is very successful when natural recovery takes place, however, the original forests were composed of Holm oaks (Quercus ilex subsp. rotundifolia L.). There is little information about the hydrological and erosional impact of this change of vegetation cover stimulated by a millennia old forest use in the Mediterranean, and a century old afforestation policies and natural recovery as a consequence of land abandonment. To get insights in the effect of plant species on runoff generation and soil erosion, individual trees should be selected. Plots of 1 m2 are necessary to identify homogeneous patches, and were installed under Aleppo pine (4 plots) and Holm oaks (4 plots) in a 30(34)-years old plant cover recovered after a forest fire that took place in 1979. A raingauge was installed in the study site to characterize the rainfall. The soil erosion plots were built with metal borders and each plot drained to a collector (gutter) and a 60 L container to store the surface runoff. Runoff was measured after each rainfall event and sediment concentration was determined by desiccation. Results show that Aleppo pine covered soils yield six times more runoff (232 mm, 8.31%) than Holm oaks (40 mm, 1.4%) during the experimental period of 2010–2014, when rainfall amount 2,721.1 mm. Runoff sediment concentration was higher in the Aleppo pine plots (4.9 g l−1) than in the Holm oaks plots (2.6 g l−1). Soil erosion rate was ten times higher in Aleppo pine (2.6 Mg ha−1 y−1) than in Holm oaks (0.26 Mg ha−1 y−1).

BackgroundSome evidence suggests that forests attract rain and that deforestation contributes to changes in rainfall and temperature. The evidence, however, is scant, particularly on smaller spatial scales. The specific objectives of the study were: (i) to evaluate long-term trends in rainfall (1970–2009) and temperature (1981–2009) and their relationships with change in forest cover, and (ii) to assess the influence of remnant forests and topographical factors on the spatial variability of annual rainfall.MethodsThis study investigated the forest-rainfall relationships in the Central Rift Valley of Ethiopia. The study used 16 long-term (1970–2009) and 15 short-term (2012–2013) rainfall and six long term (1981–2009) temperature datasets. Forest and woodland cover decline over the past 40 years (1970–2009) and the measured distances between the remnant forests and rainfall stations were also used. The long-term trends in rainfall (1970–2009) and temperature (1981–2009) were determined using Mann-Kendall (MK) and Regional Kendall (RK) tests and their relationships with long-term deforestation were evaluated using simple linear regression. Influence of remnant forests and topographical variables on the spatial variability of rainfall were determined by stepwise multiple regression method. A continuous forest and woodland cover decline was estimated using exponential interpolation.ResultsThe forest and woodland cover declined from 44% in 1973 to less than 15% in 2009 in the Central Rift Valley. Annual rainfall on the valley floor showed an increase by 37.9 mm/decade while annual rainfall on the escarpments/highlands decreased by 29.8 mm/decade. The remnant forests had a significant effect (P-value 2 = 0.40) on the spatial variability of the number of rainy days observed over two years (2012–2013), but had little effect on the variability of rainfall distribution. For the total annual rainfall, slope was the best predictor which explained 29% of the rainfall variability in the Central Rift Valley. For the annual number of rainy days, both slope and elevation explained most of the variability (60%) of annual number of rainy days.ConclusionThis study did not find a significant correlation between long-term rainfall trend and forest and woodland cover decline. The rift valley floor warmed significantly due to long-term deforestation in the Central Rift Valley. Topographic factors play a significant role than forest cover in explaining the spatial variability of annual rainfall in the long-term and short term time scale in the Central Rift Valley. But, the short-term rainfall data indicated that the remnant forest had a significant effect on the spatial variability of the number of rainy days.

Globally, it is estimated that 20 million hectares of arable land are irrigated with water that contains residual contributions from domestic liquids. This potentially poses risks to public health and ecosystems, especially due to heavy metals, which are considered dangerous because of their potential toxicity and persistence in the environment. The Villavicencio region (Colombia) is an equatorial area where rainfall (near 3000 mm/year) and temperature (average 25.6 °C) are high. Soil processes in tropical conditions are fast and react quickly to changing conditions. Soil properties from agricultural fields irrigated with river water polluted by a variety of sources were analysed and compared to non-irrigated control soils. In this study, no physico-chemical alterations were found that gave evidence of a change due to the constant use of river water that contained wastes. This fact may be associated with the climatic factors (temperature and precipitation), which contribute to fast degradation of organic matter and nutrient and contaminants (such as heavy metals) leaching, or to dilution of wastes by the river.

This study assesses potential impacts of climate change on maize and wheat yields in the Central Rift Valley (CRV) of Ethiopia. We considered effects of elevated atmospheric carbon dioxide (CO2) and changes in rainfall during the main (Kiremt) and the short (Belg) rainfall cropping seasons during the two future periods (2020–2049 and 2066–2095). The MarkSimGCM daily weather generator was used to generate projected rainfall and temperature data using the outputs from ECHAM5 general circulation model and ensemble mean of six models under A2 (high) and B1 (low) emission scenarios. Crop yield simulations were made with the FAO’s AquaCrop model. The projected rainfall during Kiremt increases by 12–69 % while rainfall during Belg decreases by 20–68 %. The combined effect of elevated CO2 and projected climate factors increases maize yield by up to 59 % in sub-humid/humid areas of the CRV, but could result in a decrease of up to 46 % in the semiarid areas under ECHAM5 model. However, the maize yield increases in all parts of the CRV under the ensemble mean of models. Wheat yield shows no significant response to the projected rainfall changes, but increases by up to 40 % due to elevated CO2. Our results generally suggest that climate change will increase crop yields in the sub-humid/humid regions of the CRV. However, in the semi-arid parts the overall projected climate change will affect crop yields negatively.

Preventing the off-site effects of soil erosion is an essential part of good catchment management. Most efforts are in the form of on-site soil and water conservation measures. However, sediment trapping can be an alternative (additional) measure to prevent the negative off-site effects of soil erosion. Therefore, not all efforts should focus solely on on-site soil conservation but also on the safe routing of sediment-laden flows and on creating sites and conditions where sediment can be trapped. Sediment trapping can be applied on-site and off-site and involves both vegetative and structural measures. This paper provides an extensive review of scientific journal articles, case studies and other reports that have assessed soil conservation efforts and the sediment trapping efficacy (STE) of vegetative and structural measures. The review is further illustrated through participatory field observation and stakeholders’ interview. Vegetation type and integration of two or more measures are important factors influencing STE. In this review, the STE of most measures was evaluated either individually or in such combinations. In real landscape situations, it is not only important to select the most efficient erosion control measures but also to determine their optimum location in the catchment. Hence, there is a need for research that shows a more integrated determination of STE at catchment scale. If integrated measures are implemented at the most appropriate spatial locations within a catchment where they can disconnect landscape units from each other, they will decrease runoff velocity and sediment transport and, subsequently, reduce downstream flooding and sedimentation problems.

Fluvial dynamics in riverine borders can play an important role in political relationships between countries. Rivers move and evolve under the influence of natural processes and external drivers (e.g. land use change in river catchments). The Hirmand River is an important riverine border between Iran and Afghanistan. The present study shows the evolution and lateral shifting of the Hirmand River along the international border (25.6 km) over a period of 6 decades (1955–2015). Seven data series of aerial photos, topographic maps and Landsat images were used to analyze land cover and channel changes in the study reach. The land cover has changed dramatically on both sides of the border during the last 6 decades, especially in the Afghan part. Overall, 49% of all land surface changed its cover type, especially the area of agriculture and residential land contributed to that, with an increase in surface area of about 4931 ha and 561 ha, respectively. On the other hand, the natural cover and water bodies decreased to 38% and 63%, respectively. The impact of these land use changes on the morphological evolution of Hirmand River was investigated in 5 sub-reaches. We found an average decrease of the active channel width of 53% during 60 years and the average River Network Change Index for the whole study reach during 60 years was − 1.25 m/year. Deposition and narrowing turned out to be the main processes occurring within the study reach. Furthermore, due to natural riverine processes the Hirmand River has moved towards Afghanistan (37 m on average) and lateral shifting was found to be up to 1900 m in some sections.

Water is a key strategic resource, particularly in Mediterranean climate-type areas with impermeable rocks and shallow soils like Southwestern Spain. The region of Extremadura is commonly known by its large surface occupied by big dams (30% of water dammed in Spain) although this theoretical abundance of water does not hide other problems of use. In this study, we have interviewed 132 people from the municipality of Arroyo de San Serv&aacute, n in order to know what the problems related to water use are, especially those that concern local people the most. Regarding the use of water at home, 90% of interviewees spend less than 60 EUR per month for water and their mean degree of satisfaction about the service is 3.7 out of 7. The reason for this low value can be the excessive content of calcium and bad taste according to 82.1%. Therefore, 64.2% of people do not usually drink water from the tap. Around two thirds of these local people usually buy water in the supermarket or drink filtered water. Concerning agricultural activities, local people gave great importance to irrigation as a source of employment (5.6/7) and inputs (4.5/7), although their satisfaction decreases about the current price of water for agriculture (0.02 EUR m&minus, 3). In addition, they are really worried about the overuse of fertilizers and herbicides (5.4/7) and they think about the necessity of taking measures to reduce these problems (6.1/7) as well as to reduce some management problems such as supply cuts. In the last few years, private (swimming pools) and public leisure facilities (swimming pool and spa) have been built in spite of not being considered important by local people (3.6&ndash, 4.0/7). Nevertheless, about 60% of them consider these common facilities very positive in terms of employment, tourism attractions and entertainment for local people.

Connectivity has emerged in recent years as a significant conceptual framework within which to address the spatial and temporal variability in runoff and sediment transport. This special issue draws together several of the papers that were presented in the session “Connectivity in water and sediment dynamics: how do we move forwards?” at the 2012 General Assembly of the European Geosciences Union in Vienna, Austria. The papers submitted for this special issue fall into three groups: empirical studies, modelling studies, and conceptual development. Although it may be evident that the concept of connectivity helps us to express the complexity (in terms of water and sediment yields) of landscape responses to rainfall inputs, does it improve our ability to understand or predict those responses? There would still seem to be some way to go in connectivity research before this nagging concern can be assuaged. That it can be will undoubtedly be an important task for a number of ongoing research initiatives.