Search

In this short paper some examples of tafoni and similar features of cavernous weathering are described from Western Scotland and Southern Greece, including Crete and the Santorini group. All these forms belong to the younger Holocene. This age is indicated by young tectonic emergence from the sea, historical data, or the well known volcanic history of Santorini. Pre-Holocene tafoni are neither more widespread nor better developed than those of the last 2000 or 3000 years. Very different rocks are weathered into tafoni features: old and young sandstones and calcareous sandstones, pliocene conglomerates, eolianites, or lavas and holocene tephra. The tafoni are nearly in all cases strongly oriented towards the present sea front, and therefore salt weathering should be the most effective process.

Phosphoric fertiliser has enormously contributed to agriculture; however, it generates five tonnes of phosphogypsum per ton of phosphoric acid synthesised. Phosphogypsum houses heavy metals and long-lived radioactive elements that represents an environmental issue requiring remediation. This paper presents a methodology for characterising phosphogypsum deposits using geophysical, geochemical, and statistical tools. Gamma-ray probes determined the abnormal radioactive zones within the phosphogypsum deposits while electrical resistivity tomography provided the geometry and distribution of the phosphogypsum deposits. Chemical results confirmed the high presence of heavy metals in the waste determining chromium as the most concentrated metal. Radiological measures indicate that the effective ambient dose equivalent average in the study area surface is approximately 8.5 times higher than the average for Europe. While at 1.0 m depth, in the phosphogypsum layer, the ambient dose equivalent average surpasses approximately 27 times the European average. Statistical correlation analysis supports that the radiation increases due to the uranium presence. This methodology might reduce time and cost avoiding the use of expensive traditional methods, and it is exportable to any deposit. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

[EN] In many Mediterranean areas, citrus orchards exhibit high soil loss rates because of the expansion of drip irrigation that allows cultivation on sloping terrain and the widespread use of glyphosate. To mitigate these non-sustainable soil losses, straw mulch could be applied as an efficient solution but this has been poorly studied. Therefore, the main goal of this paper was to assess the use of straw mulch as a tool to reduce soil losses in clementine plantations, which can be considered representative of a typical Mediterranean citrus orchard. A total of 40 rainfall simulation experiments were carried out on 20 pairs of neighbouring bare and mulched plots. Each experiment involved applying 38.8 mm of rain at a constant rate over 1 h to a circular plot of 0.28 m(2) circular plots. The results showed that a cover of 50% of straw (60 g m(-2)) was able to delay the time to ponding from 32 to 52 s and the time to runoff initiation from 57 to 129 s. Also, the mulching reduced the runoff coefficient from 65.6 to 50.5%. The effect on sediment transport was even more pronounced, as the straw mulch reduced the sediment concentration from 16.7 g l(-1) to 3.6 g l(-1) and the soil erosion rates from 439 g to 73 g. Our results indicated that mulching can be used as a useful management practice to control soil erosion rates due to the immediate effect on high soil detachment rate and runoff initiation reduction in conventional clementine orchards on sloping land, by slowing down runoff initiation and by reducing runoff generation and, especially, sediment losses. We indirectly concluded that straw mulch is also a sustainable solution in glyphosate-treated citrus plantations., This paper is part of the results of research projects GL2008-02879/BTE, LEDDRA 243857 and RECARE-FP7 (ENV.2013.6.2-4).

Agricultural terraces are common in mountain regions. They are built to provide a larger surface area for cultivation on hillslopes and to aid farming production in the long term. This paper reviews the hydrological and geomorphological behaviour of constructing, working on and abandoning farming terraces based on recent scientific papers (1982–2014). Terraces increase infiltration and reduce runoff. In Mediterranean areas, the runoff coefficient on abandoned terraces is between 20% and 40%, depending on the percentage of plant cover or the amount of grazing. On cultivated terraces in warm, humid climates, the coefficients are lower (10%–25%). The internal and external sections of terraces have hydrological differences. Soil saturation is reached faster in the inner parts of terraces with shallower soil, causing a rapid hydrological response (saturation runoff); high infiltration rates in external sections can generate subsurface runoff. Furthermore, a reduction in hydrological connectivity, which affects the contributing areas and peak flows, is to be expected in terraced catchments. Collapsed stone walls, small mass movements, sheet wash erosion, piping, rills, gullies and debris flows are all found in terraced landscapes. The erosion of abandoned terraces is directly related to the amount of plant cover, soil characteristics, environmental conditions and the abandonment age. On this type of terrace, the rates of erosion due to overland flow are less than 3 t ha− 1 yr− 1. The rate increases if the terrace is affected by mass movements, pipes or gullies (more than 100 t ha− 1 yr− 1). On cultivated terraces, erosion rates less than 1 t ha− 1 yr− 1 have been recorded for rice crops, and erosion rates greater than 80 t ha− 1 yr− 1 have been recorded for cassava or terraces with bare soil. The scientific literature notes that the soil loss from cultivated slopes is greater if conservation measures, such as terraces, are not included. However, this general result may vary significantly due to factors related to the geo-environmental characteristics of the region and, in particular, the management and use of the terraced slopes., Support for this research was provided by the project INDICA (grant n° CGL2011-27753-C02-01 and CGL2011-27753-C02-02), which was funded by the Spanish Ministry of Economy and Competitivity.

Soil and vegetation are interacting factors controlling erosion. Soil degradation processes may affect the normal tree and shrub development and inversely, vegetation can modulate the velocity and intensity of soil development or denudation. A dendrogeomorphological approach can be used to study these interactions, allowing to obtain a date and estimate mean or specific erosion rates. This is especially useful in an unrecorded badlands and gullied environments,where the scarce vegetationmay be the only proxy available to quantify the different geomorphic processes which have occurred. This paper provides a fundamental review of the dendrogeomorphological methodology applied to erosion measurement in badlands. Focusing on the response of the vegetation to the geomorphic processes, this paper: (a) describes themethodology developed to estimate erosion rates with exposed roots; (b) shows newadvances through case studies; and finally, (c) discusses future lines of research to reduce methodological uncertainties and for making dendrogeomorphology more widely applicable.

Sedimentological connectivity within drainage systems may be controlled spatially by ‘pockets’ of intact valley fill, alluvial fans impinging laterally on mainstem rivers, floodouts impinging longitudinally on valley floors, and downstream resistant rock bands and their effect on valley width. Where local conditions favor prolonged inundation of the uppermost ~ 0.5 m of the sediment surface, these environments of deposition host wetlands that provide several ecosystem services to society. In this paper, we examine the long-term (millennia), large-scale mediation of connectivity by geological and geomorphological controls, highlighting the relationship between drainage disconnectivity and wetland origin, and appraise ongoing rehabilitation efforts in light of the long-term natural dynamic. The paper uses a wetland system in the KwaZulu-Natal Drakensberg Foothills, eastern South Africa, as a case study, focusing particular attention on part of the system in which cut-and-fill processes are evident, and proceeds, using observations from this and other similar wetland systems in the region, to discuss successive breaks in connectivity with increasing spatial scale and time. Implications for valley morphology are discussed, and channel incision is shown to play an important role in long-term valley and wetland morphodynamics in certain geomorphological settings, creating a diversity of geomorphological features and hydrological regimes. Thus, rehabilitation practitioners should focus on interventions that improve or stabilize desired functional outcomes, rather than on restoring or maintaining what is perceived to be ‘the natural dynamic’ in which erosion is absent.

It is widely admitted that changes in land use land cover (LULC) influence the hydrology of the catchment. However, how these changes affect hydrological model prediction uncertainty is still a raising question. In this paper we addressed this question by investigating the impacts of the rapid change in LULC in the Siliana catchment in Tunisia on monthly flow and magnitude of flow extremes using the SWAT hydrological model while quantifying the contribution of LULC to the model parameter and prediction uncertainty. At a first step, the SWAT model parameter and prediction uncertainty were estimated using the GLUE method and acceptable parameter sets were identified. Subsequently, the SWAT model was fed with historical LULC as derived from Landsat 5 and 8 satellite images for the years 1990, 2000, 2013 and 2019, and run with the acceptable parameter sets. The results show that the increase in olive plantations (+380 %), urban area (+200 %), and irrigated lands (+309 %) from 1990 to 2019, has LULC decreased monthly flow, high flows magnitude but did not impact low flows in particular over the previous two decades. The findings also suggest that model prediction uncertainty can mask LULC effects, suggesting that model results can be misleading without explicit consideration of uncertainty when assessing the hydrological impacts of changes in LULC.

At a global scale, intertidal areas are being reclaimed for agriculture as well as urban expansion, imposing high human pressure on the coastal zone. The Ganges-Brahmaputra Delta (GBD) is an exponent of this development. In this delta, land reclamation accelerated in the 1960's to 1980's, when polders were constructed in areas subject to regular marine flooding. A comprehensive analysis of tidal channel evolution in the southwest GBD reveals how land reclamation leads to tidal amplification, channel shoaling, bank erosion, and interaction between channels in which one tidal river captures the storage area of a neighbouring river. We identify-two positive feedback mechanisms that govern these morphological changes. First, reclaiming intertidal areas results in immediate loss of tidal storage, which leads to amplification and faster propagation of the tides. In systems with abundant sediment supply, the blind tidal channels progressively fill in with sediment, leading to a continued loss of tidal storage and therefore further distorting the tides. Secondly, when intertidal areas of parallel (and inter-connected) river delta distributaries are asynchronously or unevenly reclaimed, one channel distributary may expand its intertidal area at the expense of the other. This is initiated by an increasing propagation speed of the tidal wave in the partially reclaimed distributary, travelling into the non-reclaimed distributary through connecting channels. These connecting channels progressively expand while the pristine channel shoals, and potentially degenerates. Both positive feedback loops are very stable and are responsible for pluvial flooding of polders, large-scale bank erosion, and poorly navigable primary waterways, including the navigation channel accessing Bangladesh's second-largest port. Interventions aiming to solve these problems have to account for the complex positive feedback mechanisms identified in this paper and be nature-based and holistic.

The Mediterranean mountainous landscapes have undergone large-scale exploitation for millennia. In the Central Pyrenees, land abandonment has occurred since the 1950s, leading to a process of woody encroachment. The main objective of this paper is to shed light on the effects of different land use and land covers (LULCs) on soil organic carbon (SOC) and nitrogen (N) stocks, and on the composition of soil organic matter (SOM) after land abandonment in the Central Pyrenees. Five LULCs (8 specific sites) were selected through detailed land use change mapping. Soil and litter samples (n = 160) were collected and analyzed, including Tetramethylammonium hydroxide pyrolysis–gas chromatography. Organic carbon (Corg)/N ratios, Carbon Preference Index and Average Chain Length indices were calculated based on the distribution of fatty acids in order to determine the molecular composition and degradation of SOM. The results showed: (i) an increase in the dominance index and forest cover, at the expense of shrublands and agricultural fields, and a decrease in Shannon’s Diversity and Evenness indexes; (ii) LULC and depth had significant effects on SOC and N contents and stocks; (iii) SOC and N contents and stocks were higher in the meadows and young forests; (iv) significant differences were observed between meadows and young forests and the first stages of land abandonment considering the soil profile; (v) total decomposition of lignins and an omnipresence of unsaturated and saturated straight-chain fatty acids; and (vi) Corg/N values indicate that the origin of SOM is microbial. This study confirms that SOC accumulation after abandonment is a slow process, and the first stages of the woody encroachment decrease SOC stocks. Woody encroachment should be managed with measures based on scientific knowledge, but also considering the historic adaptation of agro-pastoral activities to the environment to ensure the proper functioning of ecosystem services and promote SOC storage in Mediterranean mountain soils.

Groundwater abstraction is among the main anthropogenic causes of wetland desiccation worldwide, and corrective measures must be taken to avoid degradation of this valuable ecosystems. A case study is the Agua Amarga salt marsh (≈180 ha) (SE Spain). Agua Amarga includes a solar saltwork pond network in operation between 1925 and 1975, when it was abandoned, and the ponds were colonized by salt marsh vegetation. In 2008 two desalination plants were operating in the marsh vicinity, which were supplied with groundwater. To mitigate the possible negative impact on the salt marsh ecosystem due to groundwater drawdown, in 2009 a sea water irrigation program was implemented. This paper summarizes the results of a ten-year monitoring program (2010–2020) to evaluate the effects of the irrigation program on groundwater levels and quality, soil salinity and moisture, and vegetation cover. During this period, average groundwater level was 2.5 m below the surface and around 1 m deep near the irrigated ponds. Groundwater salinity was not affected outside the saltmarsh, but inside, where the saltworks caused values to rise above 300 mS/cm, it decreased more than 150 mS/cm in some 20 m deep piezometers. Between 2012 and 2020, vegetation cover increased between ≈10 and ≈25 %, with halophyte species such as Arthrocnemum macrostachyum and Sarcocornia fruticosa being the most favoured. In areas with prolonged flooding, Ruppia maritima, a plant species that lives submerged in saline water, was found. In the irrigated areas, soil electrical conductivity (1:5 soil:water extracts) decreased from ≈7-14 mS cm-1 to ≈2-6 mS cm-1. We present an example of sustainable actions in a coastal wetland, where the exploitation of water resources in semiarid areas is combined with promoting natural habitats. Financial support for this research was provided by Mancomunidad de los Canales del Taibilla (http://www.mct.es). M.N. González-Alcaraz holds a Ramón y Cajal research contract from the Spanish Ministry of Science and Innovation (RYC2020-029322-I). We much appreciate the help of M. Carmen Tercero, Héctor M. Conesa and B. Aránega, from Technical University of Cartagena, and Francisco J. Jiménez-Cárceles, from Biocyma environmental consulting, during field and laboratory work. We thank to the technicians of the SAIT-UPCT for their laboratory and analytical assessments. Finally, we want to give special recognition to Doctor Tomás Rodríguez Estrella for his contributions in the field of hydrogeology.

This study uses the Global Assessment of Soil Degradation (GLASOD) to map sediment sources and erosion process types within the Congo Basin as part of a scoping study to guide a basin wide sedimentation study. The GLASOD map is validated using information from literature and published sediment concentration data at the Brazzaville gauging station, which includes over 95% of the basin area. Validation is complemented by analysis of timelapse satellite images and surface water transition maps derived from Landsat images. The upper catchments are shown to be the main sources of sediment, with the largest exporter by quantity being the Upper Congo sub-basin followed by the Kasai. In terms of severity, the Kasai has the highest specific sediment production rates at 8.92 t/km2/year, followed by the Sangha and Upper Congo at 8.52 t/km2/year and 7.61 t/km2/year, respectively. The dominant erosion/degradation type is the loss of topsoil through water erosion (sheet erosion), occurring in 32% of the entire Congo Basin area, followed by loss of nutrients and organic matter through chemical degradation, 21% of area. The mapping also shows that a large proportion of the Basin (39%) consists of stable terrain under natural conditions, without any human induced erosion. The erosion levels in the Basin are generally low with the predominant mapped erosion processes occurring mostly infrequently and with low levels of severity. The GLASOD map performs satisfactorily as a tool for mapping erosion sources and process types, but fails to explain the process dynamics within the sub-basins, for example, the high sediment exportation rates published for the Sangha sub-basin despite consisting mainly of stable natural terrain (84%). Analysis of satellite images shows an increase in sediment concentration in the Congo River's waters over the years. However, this temporal increase in sediment concentration is neither reflected in the GLASOD map nor the quantitative studies reviewed for this paper, pointing to the urgent need for future research on sediment dynamics in the Basin. Questions are also raised on the roles of the Malebo Pool and Cuvette Centrale in the sediment transport processes of the Basin. The questions raised, and observations made from this study have been used to identify strategic sampling sites for further field studies.

Soils in botanical gardens play a crucial role as they condition the growth and vegetation of huge diversity of plant species on relatively small areas. Creating favourable habitats for the planted vegetation's development frequently leads to the formation of soils with thick surface horizons with a very well developed structure, rich in organic matter and nutrients, described as hortisols. Despite significant human influence, the environments of botanical gardens are often considered to be seminatural enclaves in urban areas. The main objectives of the presented paper were to explain soil cover differentiation noted across the Botanical Garden of Jagiellonian University in Krakow and determine the share of natural and anthropogenic features in the studied soils. Moreover, the usefulness of the WRB system in the evaluation of the rate of anthropogenic transformation in soils was tested. All the investigated soils showed significant evidences of anthropogenic transformations. Both digging and overbuilding with allochthonous material rich in artefacts caused disturbances in soil morphology. On the other hand, formerly intensive liming and fertilizing with organic materials has resulted in the homogenization of soil chemical properties in the studied botanical garden. No significant relationships between the spatial differentiation of soil properties and diversity of planted vegetation or time span from the area's inclusion to the botanical garden were detected. The results of the bonitation of specific soil properties not considered by the classification system (e.g. thickness of soil profile overheap) were compatible with the WRB 2015 systematic position. This confirmed good definition of actual WRB criteria for soils disturbed by human activity and undergoing natural development.

The carbon cycle is being altered as a result of human-induced changes in the Earth's system. Therefore, ecosystems such as wetlands, authentic CO2 sinks, are becoming especially important. Little information exits on the soil organic carbon (SOC) stock for the middle east-countries man-made wetlands making wadis permanent with the outflow of wastewater treatment plants. This paper presents the vertical distribution of SOC content, soil bulk density (SBD) and SOC density in soil of vegetated and bare sites in Wadi Al-Thulaima, one of the artificial wetlands in central Saudi Arabia. The mean distribution of SBD in the vegetated and bare sites increased significantly with depth. Inversely, the SOC content declined significantly with depth, from 17.1 g C kg−1 at 0–3 cm depth to 3.3 g C kg−1 at 15–18 cm depth in vegetated sites and from 4.7 g C kg−1 at 0–3 cm depth to 0.7 g C kg−1 at the 15–18 cm depth in bared sites. Vegetation significantly affected the SOC pool, the total mean SOC pool of the vegetated sites (2.0 kg C m−2) was higher than that of the bare sites (0.5 kg C m−2). Therefore, arid regions could contribute to carbon sequestration with appropriate management, which would result in the enhancement of soil quality., The financial support from the Distinguished Scientist Fellowship Program (DSFP) from King Saud University, Saudi Arabia is gratefully acknowledged.

This paper portrays the application of Fuzzy Cognitive Maps (FCMs) to elicit expert views on current condition and future scenario of coastal susceptibility to erosion in Bangladesh. The geomorphological characteristic of the coastal area is highly dynamic where land erosion and accretion with different rates are constant phenomena. This research focuses on three coastal zones: western, central and eastern that comprise the entire coastal area of the country. Using ‘Mental Modeler’ software this study quantified experts' judgements on the issue and developed FCMs by way of arranging workshops. At the basis, this study identified 33 factors of susceptibility to erosion for current baseline conditions. Considering future projections of hydro-climatic phenomena, this study accentuated potential factors of susceptibility to erosion for future scenario under three time-slices: near-future (2020), future (2050) and far-future (2080). The results generated from FCMs show that some factors such as sedimentation, soft and unconsolidated soils, shelf bathymetry, funnel shape of the Bay of Bengal, wave action, river discharge, monsoon wind, cyclone and storm surges, excessive monsoon rain, high tidal energy, variations of tidal range and sea level rise are highly influential that yielded higher centrality scores for both current and future susceptibility of the area to erosion. The experts' interpretations demonstrate that the future susceptibility to erosion might be higher in the central zone compared to the western and eastern zones of the coastal area. This is the first time that FCM based approach was applied to evaluate expert views on coastal susceptibility to erosion for the country. This study suggests coastal managers, planners and policymakers to consider the current and future factors of susceptibility of coastal lands for taking specific measures options. This study is also significant from socio-economic and demographic contexts of any densely populated coastal area like Bangladesh.

In this paper, we examine the effect of vegetation on soil erosion, runoff generation and sediment transport on saline rangeland hillslopes. Rainfall simulations were conducted at a fixed 114 mm/h intensity on 6 m × 2 m erosion plots with varying degrees of vegetation. Plots were grouped into three categories (L, M and H) based on their canopy cover (L: 19%) and selected to limit variations in slope across canopy cover groups. Runoff and sediment samples were combined with three dimensional (3D) reconstruction data used to monitor soil surface microtopographic changes. Runoff initiation was significantly delayed on the L plots but cumulative runoff after 20 min of rainfall simulation indicated a positive effect of vegetation on infiltration processes. Cumulative sediment after 20 min of rainfall was similar across vegetation cover categories. The 3D data suggest that vegetation reduced net sediment delivery from the plots by primarily increasing opportunities for deposition while marginally affecting gross soil erosion. Plots with H vegetation cover experienced lower 3D-estimated erosion volumes but average erosion depth on L plots was lower than that on plots with M and H vegetation covers. Lower runoff volumes on M and H plots may have been compensated by greater runoff erosivity on these plots as runoff was concentrated in a narrower inter-patch space compared to L plots. This study highlights the need for an increased integration between traditional runoff measurement techniques and 3D reconstruction methods.

Landslides are widespread natural phenomena that play an important role in landscape evolution and are responsible for several casualties and damages. Slope instability is linked to the combination of geological, geomorphological, and climatic factors with various triggering mechanisms; among these, seismic shaking can induce relevant changes in the landscape, leading to coseismic and post-seismic phenomena such as landslide events. The Abruzzo Region (Central Italy) is severely affected by Earthquake-Induced Landslides (EILs), linked to the geomorphological dynamics and the severe seismicity of the area. The distribution, mechanisms, and typology of landslides are strictly related to the different physiographic and geological-structural settings. This paper focuses on the realisation of an EILs susceptibility map, following a heuristic approach combined with a statistical analysis, integrated using GIS technology. This approach led to the identification of nine instability factors. These factors were analysed for the construction of thematic maps. Hence, each factor was assigned proper expert-based ranks and weights based on the critical evaluation of literature data as well as on available landslide inventories and combined in a preliminary map wherein high/low numerical values correspond to a high/low propensity of the slope to fail; furthermore, a statistical analysis of these values was performed to derive suitable susceptibility classes. Results presented herein highlight the robustness of the approach; remarkably, the applied methodology is suitable even in areas where a detailed landslide catalogue is lacking, when the same classification and weighting of available parameters is performed. The statistical analyses and the adoption of an absolute scale ranging from minimum to maximum potential values, finally, ensures the comparability of results among different study areas. Finally, this work represents a scientific and multidisciplinary tool for better defining situations that could lead to hazards (such as landslides) following an earthquake to develop sustainable territorial planning, emergency management, and loss-reduction measures.

In this paper, we studied the soils of recreational areas of Volgograd within three research areas. The survey found that in research area I the soils spatial distribution is mainly represented by the following soil group according to WRB: Urbic Technosols, Urbic Technosols (Mollic) and Gleyic Terric Phaeozem (Mollic, Prototechnic). Buried soils are represented by Gleic Cambisols (Protocalcic). In research area II, among natural soils, the largest areas are occupied by Calcaric Fluvisols (Loamic, Technic, Protovertic), Calcaric Fluvisols (Arenic, Salic), and Gleyic Calcisols (Sodic, Protocalcic, Technic, Salic). The anthropogenic-transformed soils include Urbic Technosols, and Ekranic Technosols are under buildings and road surfaces. In research area III, the natural soils spatial distribution is homogeneous and mainly represented by Gleyic Cambic Calcisols (Protocalcic), Gleyic Cambisols (Protocalcic, Prototechnic), and Calcaric Colluvic Regosols (Arenic, Prototechnic) in the bottoms of small flat-bottom valleys. In irrigation sites occur Urbic Technosols, and on hiking trails – Gleyic Cambisols (Prototechnic). Despite the presence of reclaimed horizons with a high content of phosphorus in the soils (average concentration of 82 mg kg−1), none of the profiles revealed Hortic horizon, but only some of its properties (colour, horizon thickness, zoogenic activity). The thickness of urbic-stratifying layer (Au) varies in a wide range from 10 to 135 cm, and the thickness of reclaimed horizons (A) also varies from 10 to 48 cm. The bulk density in Au horizons is 1.4 g cm−3, in the reclaimed horizons (A) – 1.39 g cm−3. The content of soil carbon in soil surface horizons varies from 0.85% to 4.58% in urbic horizons, and to 1.49% in reclaimed horizons. Chemical analysis of urbic (Au) and reclaimed (A) horizons revealed a low content of easily soluble salts (0.16%) and carbonates (1.5% and 1.7%, respectively).

Sedimentation in the Three Gorges Reservoir (TGR) affects flood control, navigation, power generation and the ecological environment. We present a comprehensive analysis of the characteristics of sedimentation in the TGR from 2003 to 2018. The data set includes field measurements (runoff and sediment) at hydrological stations and estimation for areas where measured data are not available. Based on the data set, the amount of sedimentation in the TGR was calculated with the Sediment Budget Model (SBM) and Section Topography Method (STM). Finally, the variation in sediment Trapping Efficiency (TE) in the TGR was assessed. The results indicate that sediment from smaller tributaries in the TGR region, which has been ignored in most previous studies, constituted approximately 10.8% of the total incoming sediment. The total sedimentation in the TGR was 205478 × 104 t in 2003–2018, and the contribution rates of sediment load flowing into the TGR, the water depth in front of the dam, and runoff discharge flowing into the TGR were 94.4%, 24.5% and −18.9% respectively. The average annual TE was 78.5% in 2003–2018, and it was closely related to the ratio of reservoir storage capacity to flow discharge in the flood season and to sediment concentration in the non-flood season. The results in this paper not only play an important role in the optimal operation of the TGR but also have important reference value for other large reservoirs worldwide.

For many geoscience applications, the quality of digital elevation models (DEMs) is the first and foremost requirement. DEM quality generally depends on the interpolation procedure, especially in forested areas with complex terrain. However, classical interpolation methods do not always preserve terrain features, owing to their isotropic and local estimation nature. Therefore, this paper presents a feature-preserving interpolation method, where a structure tensor is integrated into the radial basis function to ensure its anisotropy. This method alleviates the influence of points located on different surface patches. The performance of the proposed method was compared with those of classical interpolation methods, including the inverse distance weighting (IDW), ordinary kriging (OK), topo to raster (ANUDEM), and natural neighbour (NN) methods. The performance of these methods was tested on benchmark data provided by the International Society for Photogrammetry and Remote Sensing (ISPRS) Commission, and on one private dataset. Both datasets were collected via the airborne light detection and ranging (LiDAR) technique. The results from both datasets demonstrate that from a quantitative perspective, the proposed method produces more accurate DEMs than the classical interpolation methods. Specifically, in terms of root mean square error (RMSE), the proposed method is at least 15.8% and 7.6% more accurate when applied to the ISPRS and private data, respectively. Moreover, the proposed method produces more visually appealing surfaces with a good trade-off between terrain feature retention and noise removal.

Global warming has significantly affected the terrestrial C and N cycling processes. Whereas, it is unclear how global warming impacts the C and N concentrations in the above- and belowground ecosystems. We performed a meta-analysis with the results presented in 136 papers and 1886 observations. The data reveals that global warming increased C concentrations in leaf, shoot, and microbial biomass and N concentrations in the shoot. The C:N ratios of microbial biomass also increased under conditions of warming. However, the soil C concentration and soil C:N ratios decreased. Furthermore, these responses are more evident with longer warming duration and elevated warming magnitudes. The warming effects on C and N concentrations and C:N ratios never changed with warming methods, ecosystem types, or background climates. Also, in response to warming, soil moisture was negatively correlated with leaf C concentration as well as C:N ratio in microbial biomass. Soil pH response to warming was in a negative correlation with those of soil C concentration, soil C:N ratio, and microbial biomass C concentration. Our analysis has identified some key ecosystem processes that can be potentially implemented into the ecosystem models for predicting how warming affects future terrestrial C and N dynamics.

Studies of the provenance of aeolian dunes are crucial for providing knowledge of landscape evolution and developing management strategies to control aeolian desertification. The lakeshore dune is a typical aeolian landform that is widely distributed around the world. However, there has been little work on the provenance and formation mechanism of lakeshore dunes. By comparing the elemental and grain-size compositions of lakeshore dunes and potential sources around Co Nag Lake, this paper combines sediment fingerprinting analysis and end-member modeling. The results identify the provenance of aeolian sands on the eastern bank of Co Nag Lake and draw the following conclusions. (1) The combined use of fingerprinting analysis and grain-size analysis can yield a comprehensive and reliable provenance assessment. (2) The lakeshore dunes on the eastern bank of the lake are primarily derived from lacustrine deposits and fluvial deposits on the eastern bank. The coupling of fluvial and aeolian systems promotes the development of eastern sandy land. (3) Sand-control projects in the Co Nag Lake region should be carried out according to the sources of aeolian sands. It is necessary to strengthen efforts to control lacustrine deposits and sands in gullies.

Wildfires can have strong negative effects on soil and water resources, especially in headwater areas. The spatially explicit OpenLISEM model was applied to a burned catchment in southern Portugal to quantify the individual and combined impacts of wildfire and rainfall on hydrological and erosion processes. The companion paper has calibrated and assessed model performance in this area before and after a fire. In this study, the model was applied with design storms of six different return periods (0.2, 0.5, 1, 2, 5, and 10 years) to simulate and evaluate pre- and post-wildfire hydrological and erosion responses at the catchment scale. Our results show that rainfall amount and intensity played a more important role than fire occurrence in the catchment discharge and sediment yields. Fire occurrence was found to be an important factor for peak discharge, indicating that high post-fire hydro-sedimentary responses are frequently related to extreme rainfall events. The results also suggest a partial shift from runoff to splash erosion after fire, especially for higher return periods. This can be explained by increased splash erosion in burned upstream areas saturating the sediment transport capacity of surface runoff, limiting runoff erosion in downstream areas. Therefore, the pre-fire erosion risk in the croplands of this catchment was partly shifted to a post-fire erosion risk in upper slope forest and natural areas, especially for storms with lower return periods, although erosion risks in croplands were important both before and after fires. These findings have significant implications to identify areas for post-wildfire stabilization and rehabilitation, which is particularly important given the predicted increase in the occurrence of fires and extreme rainfall events with climate change.

In the Cabo Basin, NE Brazil, conglomerates have given rise to soils with attributes that are rarely observed in humid tropical climates and remain relatively unknown within the scientific community. These soils have high levels of Al in the exchangeable phase, diminishing their agricultural and environmental potential in an underdeveloped region of great socioeconomic importance. This paper presents the mineralogy and genesis of soils derived from conglomerates on a slope in the Cabo Basin, with the aim of meeting the demand for studies on Al–rich soils. Three soils were classified, morphologically described and sampled for the accomplishment of chemical, physical and mineralogical analyses, including the main exchangeable cations content, mineralogy of the sand, silt and clay fraction, differentiation of the Fe and Al forms, mineral micromorphology and chemical composition of mineral species. In addition, chemical and physical attributes were used in multivariate analyses. The soil mineralogy is associated with the weathering evolution of three mineralogical zones identified in the Cr horizons. Pathways of alteration followed by feldspars and micas resulted in kaolinite, smectite and hydroxy–Al interlayered smectite formation (argilification). The susceptibility of the conglomerate to weathering, constant releases of Al from the structure of aluminous minerals, low contents of exchangeable bases and consequent low pH values (

The aim of this paper is to comprehensively evaluate the abiotic factors that influence changes in the annual growth rates of selected species of tundra plants (Saxifraga oppositifolia L. and Salix polaris Wahlenb.). The study was conducted in the area of the Fuglebergsletta coastal plain, in the vicinity of the Polish Polar Station (Wedel Jarlsberg Land, SW Spitsbergen). Relationships between the studied phenomenon and basic environmental factors and climate indicators were evaluated. The spatial variation of land surface temperatures (LST) was determined, as were the effects of the physical and chemical properties of soils and the spring melting of snow cover on growth rates. It has been argued that the spatial and seasonal variability of annual growth is determined by the rate at which snow cover disappears and by soil moisture, which determines plants' access to water. Soil moisture depends on soil particle size distribution and weather; it is regulated by the supply of snowmelt water and rainfall as well as by the depth of the top layer of permafrost (thaw depth), which determines the level of groundwater during the growing season. The spatial characteristics of the process of the disappearance of seasonal snow cover are co-determined by the morphology of the substrate and the physical properties of the soil. An important but destructive role is played by thawing episodes, which are increasingly frequent in the winter season, ‘rain-on-snow’ events, and glaze ice. The values of correlation coefficients indicate a positive role for precipitation and negative influence of temperature. The higher the temperature (along with low precipitation), the lesser the extent of plant growth. The observed trend towards warming in polar areas does not inevitably lead to an increase in biomass production. An increase in temperature during the growing season does not necessarily promote plant growth, but rather indicates drought stress caused by the lowering of groundwater levels related to the increase in thaw depth.

Reclamation of highly degraded mine lands to a sustainable environmental quality has become a major policy concern in many countries with a long mining tradition. This paper reports the soil quality status of a historical mine site fifteen years after its reclamation, using indicators of chemical reactivity, soil fertility and health, and discusses the progress and effectiveness of the implemented measures by a comparative analysis between pre- and post-reclamation conditions. Twenty composite surface samples (0–20 cm depth) were obtained for physical and chemical characterization from the open pit mine and waste disposal area, using a stratified random sampling approach. Additionally seven sites were selected to collect topsoil samples for microbiological testing. Results showed that soil quality changed noticeably over the study period (2003–2018), with overall improvements in key properties, such as structural stability, cation exchange capacity, degree of base saturation, soil organic carbon, and available phosphorus. Prior to reclamation, the mine soil was unable to support vegetation due to hyperacidity coupled with elevated levels of toxic metals and nutrient deficiencies. The combined use of sugar beet lime and composted biosolids as a low-cost, locally available, soil amendment was effective in neutralizing both active and exchangeable acidity, and reducing the mobility, plant uptake and human bioaccessibility of trace elements. The amendment addition also enhanced soil fertility, carbon storage, nutrient availability and microbial biomass (bacteria and fungi). Revegetation with Pinus pinea and Nerium oleander has proven to be a successful strategy to create a vegetative cover aesthetically pleasant and environmentally compatible with the surrounding undisturbed landscape, although further efforts should be made to monitor over time the phytotoxic and bioaccessible levels of residual metals, notably Cd, Cu and Zn. The insights gained from this land reclamation experience provide success criteria for assisting natural attenuation in other abandoned mining sites worldwide.

Geomorphic processes driven by water are particularly active in mountain environments, especially under the current climate conditions. Erosion and dissolution processes shape meaningful landforms, in different kinds of deposits and rocks, and in some cases they are classified as geomorphosites. Such landforms, especially earth pyramids and rock pillars, are usually characterized by a high scientific value (e.g., representativeness, ecologic support role) and by additional values (e.g., cultural and aesthetic value) contributing to the local geoheritage. Mountain geomorphosites are growing in importance within scientific community and their morphological evolution can affect the global value of the site itself (e.g., integrity). In this paper, after a first review on the terminology used for classifying landforms modelled by water runoff and on their meaning within the mountain environment, the results of a detailed research performed at two sample sites, included in the Swiss National Inventory of Geosites, are presented. The two study sites are representative respectively of: i) water runoff on glacial deposits shaping earth pyramids (Pyramides d'Euseigne); ii) water dissolution on gypsum rocks, modelling articulate karst landscapes (Pyramides de gypse du Col de la Croix). For each site, landforms evolution was investigated and denudation rates were estimated by means of different methods: iconographic material analysis, quantitative geomorphology and dendrogeomorphology on exposed roots. Despite the long-term, average rates obtained by means of roots exposure for both water runoff on glacial deposits (e.g., 5.8 mm/y) and dissolution on gypsum rocks (5.6 mm/y) are comparable. Moreover, a strict relation between the activity degree of processes, the integrity of the site and the assignment of geomorphosites to a specific category (i.e., active, passive or evolving passive) emerged from the results.

Water management in the Caatinga/Atlantic forest ecotone in Brazil is critically dependent on better understanding of potential future changes in streamflow and sediment dynamics. This paper evaluates both the future impacts of land use and land cover (LULC) changes and the impacts of climate change on the streamflow and sediment yield in the Tapacura River basin in northeastern Brazil, using a novel combination of approaches. Projected climate data derived using global circulation model HadGEM2-ES were coupled to regional circulation model ETA-CPTEC/HadCM3 for two representative concentration pathways (RCP 4.5 and 8.5), with bias correction. Two future LULC scenarios were generated: (a) optimistic (current LULC), and (b) pessimistic (land use change trends continue), using the multilayer perceptron algorithm (MP). The Soil and Water Assessment Tool (SWAT) model was used to estimate future streamflow and erosion for different periods (2011–2040, 2041–2070 and 2071–2099). The SWAT model was calibrated for period of 1995–2003 and validated for 2004–2013. The results showed good accuracy in relation to R2, NSE and PBIAS for the calibration and validation of the runoff, as well as for the verification of the sediment yield. Simulations indicated significant increases in erosion for the pessimistic scenario under RCP 8.5, followed by the pessimistic scenario and RCP 4.5. Lower sediment yields occurred for the optimistic and RCP 8.5, with lower still for the optimistic and RCP 4.5. However, the latter estimates are still considerably higher than baseline conditions. Although higher flows are found for some scenarios, the increases in sediment yield have serious implications for reservoir siltation and storage reduction. Despite modeling uncertainty, the results demonstrate that the proposed methodology has promising scope to contextualize potentially significant regional hydrological changes which have implications for land and biodiversity management and the sustainability of water resources in the Caatinga/Atlantic forest ecotone.

The paper describes river runoff modeling for a plains region of the European territory of Russia (ETR), as well as a prediction for ungauged drainage basins. The study of river runoff is one of the key research objectives in determining the patterns of sediment yield formation. Among many other zonal factors, river runoff is considered to be the main factor in sediment yield formation in a humid climate. In this study, modeling results for the entire European territory of Russia and various landscape zones are presented via the use of multiple regression methods. Multiple regression methods do not require the mathematical description of the main physical processes of runoff formation in terms of their spatial heterogeneity. At the same time, such methods can be distinguished by their simplicity in terms of determining parameters and providing clear interpretations of the results. The research methodology in this work is based on a drainage basin approach. Initial data for the river runoff and its formation factors are presented in the open-access geoinformation database “Drainage basins of the European territory of Russia”, which has been created earlier by the authors. The river runoff geodatabase was formed with results from 1440 gauging stations. The independent variables, such as the relief morphometric characteristics, climatic indicators reflecting average values, scale, seasonal variations, extreme values of temperature and precipitation, percentage of forest and swamp cover, plowing, percentage of meadows, assessment of the anthropogenic impact on the drainage basin, geographical coordinates of the centroid, prevailing soil type, type of soil-forming rock, and class of pre-Quaternary deposits are used for modeling here. Data processing and model development is conducted using the R software environment. Models obtained by linear and nonlinear methods explain about 85–88% of data variability and are well interpreted in terms of the water balance equation. It is found here that the most significant predictors in the model are annual precipitation, the sum of the active temperatures (characterizing runoff losses via evaporation), average slope gradient, and the forest cover of the catchment. For Environmental Resources Management, it is required that data for river runoff are collected at the local (municipal) level. The results for the extrapolation of the river runoff values to ungauged river basins in a plains region of the European territory of Russia are presented here. Calculations of predicted values for the river runoff are given based on the obtained discharge per unit area logarithm model. The model and its cartographic representation reflect the patterns of the spatial distribution of river runoff for the level of spatial detail accepted in the study. The methods applied in this study and the results obtained could be used for similar studies of plains territories across the world.

Shallow aquifers in many Holocene alluvial basins around the world have in the last three decades been identified as arsenic pollution hotspots, in which the spatial variation of natural (or: geogenic) arsenic concentration is conditioned by the meandering-river geomorphology and the fluvial lithofacies distribution. Despite the large amount of publications on the specifics of the pollution, still many uncertainties remain as to the provenance and processes that lead to arsenic enrichment in aquifers. In this paper, arsenic in abandoned and sediment-filled meandering-river bends (or: clay-plugs) is highlighted as a primary source of aquifer pollution. The combination of high organic-carbon deposition rates and the presence of chemically-bound natural arsenic in sediment of this specific geomorphological setting creates the potential for microbially-steered reductive dissolution of arsenic in an anoxic environment, and subsequent migration of the desorbed arsenic to, and stratigraphic entrapment in, adjacent sandy point-bar aquifers. To assess the magnitude of the arsenic source in clay-plug, bulk sediment volume calculations were made of twenty clay plugs on the Middle Ganges Plain of Bihar (India), by combining clay-plug surface area analysis of Sentinel-2 satellite data, side-scan sonar depth profiling of oxbow lakes and the Ganges River, and sedimentological data from five cored shallow wells. ICP-MS based elemental analysis of 36 core sub-samples, complemented with published concentration data in a similar geomorphological setting in West Bengal, India, yielded an average arsenic content of 28.75 mg/kg sediment in the 12-m-thick clay plugs, which amounts to a total arsenic volume of 0.07 – 3.13 . 106 kg per clay plug. A scenario is presented for the release of arsenic from the clay-plug sediment by microbial metabolism, followed by migration of the desorbed arsenic to the bordering point-bar sands. ispartof: Catena vol:202 status: Published online

The paramos biome of the northern Andes is a collection of high-mountain tropical grassland wetland ecosystems that provides important ecosystem services including hydrological buffering and water supply. Human activities in these ecosystems transform vegetation cover and soil hydro-physical properties, affecting their hydrological performance and water quality and quantity. Here, we conducted a systematic review on the influence of land use (agriculture, livestock grazing, and afforestation) on the hydro-physical properties of paramo soils and analyzed its implications for streamflow buffering. Our review protocol identified 32 relevant papers, from which key hydro-physical properties linked to streamflow variability were available: soil organic matter (SOM), soil organic carbon (SOC), porosity, bulk density, saturated hydraulic conductivity, and water retention capacity (WRC). The analysis shows that soils with native cover are characterized by a porous structure that allows a high WRC and SOM content. Agriculture increases macroporosity but it leads to bare fallow plots that promote loss of nutrients and SOM. Burning generates hydrophobic aggregates that affect WRC. Livestock grazing produces soil compaction and increases bulk density, reducing infiltration and WRC. Lastly, afforestation with exotic species (e.g. pines, eucalyptus) decreases SOM and WRC by changing soil structure. In general, the analyzed land-use activities generate hydrophobic aggregates, increase bulk density, promote erosion and runoff, and impair hydrological buffering capacity. This integrated evidence from multiple empirical studies can be used to effectively communicate the effects of different land use practices on paramo soils, provide information for modelling in data-scarce situations, and contribute to decision making processes for land use planning and conservation.

The research topic ‘parent material for soil formation’ is at the interface between the disciplines of geology and soil science; interdisciplinary research will be of mutual benefit. In order to foster such research and knowledge transfer, this paper presents the development of a novel geochemical-physical classification system for subsolum geological substrates as a basis for both understanding soil formation and estimating and modelling soil properties. It is based on information from classical geological surveys and maps and additional specific field data and laboratory analysis of surficial geology and is applicable to solid bedrock and unconsolidated deposits. In summary, the units of the classification system consist of three evaluation levels encoded in entities describing their lithogenetic, geochemical, and physical characteristics. Beside the geochemical-physical characterisation, the classification approach also considers the layer structure of unconsolidated deposits. The basis for the classification is mineral component groups of the subsolum geological substrates, namely dolomite, calcite, and felsic, mafic, and clay minerals. The categorisation is implemented in three distinct triangular diagrams with a scope of application according to the proportion of carbonate. The practical application includes the processing and classification of geological reference samples and was applied to 321 analysed field samples of unconsolidated deposits. In order to describe and evaluate the influence on soil formation and soil properties, we examined the soil analysis data of 389 and field descriptions of 1664 legacy forest soil profiles in the Tyrolean Alps. With the compiled dataset we were able to cover 50 different classification units representing approximately 92% of the forested area of Tyrol. We were able to show clear differences in the chemical and physical soil properties between units. Beside the mineral components of the parent material, the different lithogenetic entities play an important role in soil formation and soil properties. This is explained by the preliminary fragmentation of rock through different transport processes and distances as advanced soil genesis is facilitated by the presence of finer grain size. Hence, parent material is a key factor in soil formation, determining soils physical and chemical properties. The valorisation of geological information for soil science bridges the gap between the disciplines and contributes added value to other research fields. Due to the openness of the proposed classification system for the further differentiation of lithogenetic, geochemical, and physical entities, it is transferable to the entire Alpine arc and other mountain regions.

Hydraulic conductivity of a vegetated soil (i.e., mixed grass cover) is an important parameter governing the hydrological performance of green infrastructure (GI). This paper focuses on GI with mixed grass cover in the presence of trees. Due to shading effects (interception of radiant energy) of tree canopy, mixed grass cover in the vicinity of trees may not receive direct photosynthetically active radiation (PAR). This can hinder the growth rates resulting in the low grass cover (i.e., in density). The hydraulic conductivity and the performance of GI can be further affected. Several field studies were conducted to investigate hydraulic conductivity in different types of vegetated covers. However, any variation in growth and hydraulic conductivity of mixed grass cover in the vicinity of trees was rarely investigated. The objective of this study is to quantify spatial and temporal variation of vegetation growth and hydraulic conductivity in a mixed grass cover in the vicinity of a tree. Field monitoring of a mixed grass cover in the vicinity of a tree in a GI was conducted for about six months. Hydraulic conductivity tests were carried out using mini disk infiltrometer (MDI) at 149 locations in a selected site once every month. Vegetation density was quantified using image analysis and the images were captured by a DJI Phantom drone. The growth of mixed grass cover around tree vicinity (within 5 m radial distance) was found to be more uniform during months characterized by high rainfall depth. Spatial heterogeneity in both vegetation density and hydraulic conductivity is found to be more significant during a dry period than wet period. Variation of hydraulic conductivity with respect to the change in vegetation density is found to be significant in a wet period than dry period. It is also found that hydraulic conductivity is higher at the portions where shredded leaves are present. The obtained dynamic spatio-temporal relationship of soil, vegetation and atmospheric parameters can support the design of green infrastructures and contribute to a better understanding of the maintenance practices.

This paper focuses on the susceptibility evaluation to bank gullies on earthen embankments through the application of SIMWE (SIMulated Water Erosion) model, using a high resolution digital elevation model (1 meter spatial resolution). The results provided by the model are compared with the hydrologic characteristics, soil texture and soil structure of the agricultural terraces. This approach demonstrates an association between the spatial distribution of erosive forms with high values of water depth and reduced water discharge that are consistent with the lower values of electrical resistivity. The areas with the highest percentage of erosive forms, related to sediment flux, transport capacity and sediment concentration susceptibility, assume medium values. These figures, combined with a low hydraulic conductivity and soil infiltration capacity, are consistent with the fine texture of soils, allowing increased runoff and the development of linear erosion.

Farmland abandonment in Europe is a major problem because of environmental, socioeconomic and landscape implications. In this paper, a general view of the extent of abandoned land, the stages of abandonment and the drivers that manage this process in Europe is presented. A scientific literature review shows an abandonment at the beginning of the 19th century, although the largest abandonment in terms of area took place in the mid-20th century. This abandonment had a far greater impact on mountain areas because of rural depopulation as well as biophysical constraints. Since the last decades of the 20th century, abandonment driven by the CAP in European Member States and by the end of the communist regime in Central and Eastern Europe has been taking place. This abandonment affects peripheral marginal areas due to biophysical or socioeconomic conditions. Semi-arid areas in Southern Europe have also seen an important extent of abandoned land over the last few decades. The literature draws on the ongoing abandonment from the following decades, and 3–4% of current farmland is considered to be affected. It is noted that, among the drivers, external factors (migration, socioeconomic model, public policies, etc.) act as enhancers that emphasize land abandonment. However, internal causes (agro-ecological and socioeconomic factors and also the features of agricultural holdings) control the dynamics and the extent of this phenomenon. The international literature about land abandonment in Europe is vast, and most of the specialized production is devoted to the effects of land abandonment, while few works determine the extent, stages and drivers of land abandonment. Finally, it is necessary to review the grey literature to obtain more quantitative information on the amount of abandoned land in Europe.

The Assif n’Imserdane valley, located in the Jebel Toubkal area of the High Atlas, Morocco, is a highly dynamic geomorphological setting. The valley was glaciated during the Late Pleistocene, and subsequently experienced a catastrophic rock avalanche leading to the formation of one of the largest mass movement landforms in North Africa. Recent research (Hughes et al., GSA Bulletin 126: 1093–1104) has dated the formation of the rock avalanche to the mid-Holocene at 4.5 ± 0.5 ka. In this paper, we examine the sedimentological (organic matter content, magnetic susceptibility, particle size and XRF) and palaeoecological (pollen and spores, non-pollen palynomorphs (NPPs), microcharcoal and conifer tracheid fragments) record of a small infilled basin located adjacent to a Late Pleistocene moraine and close to the rock avalanche in the Arroumd sector. The deposits, primarily fine-grained and minerogenic with a low concentration of organic microfossils including pollen, coprophilous ascospores, wood and charcoal microfragments, are enriched in fine silts and ferrimagnetic minerals, consistent with erosional sources from surrounding slope soils. Three radiocarbon dates from the deposit indicate that the infill event occurred during the first millennium AD (after 430–640 AD). As such, the deposits point to a phase of slope instability and erosion that is not linked to either deglaciation processes or to the mid-Holocene rock avalanche. Instead, the nature and timing suggest that an anthropogenic trigger of degradation to the natural vegetation cover may be implicated, consistent with an increasing scale and intensity of pastoral activity in the southern High Atlas during the early Islamic period in Morocco. The record casts light on a previously undocumented phase of landscape instability in the dynamic setting of the Assif n’Imserdane valley, and highlights the potential for further exploration of small infilled basins in the High Atlas to illuminate the geoecological history of the region.

Knowledge on active-layer dynamics and permafrost distribution is of especial importance in Maritime Antarctica, where dramatic climate warming occurred in the last decades. Few long-term studies of active-layer temperatures in this region, and no one focus on recently deglaciated areas under paraglacial conditions. This paper analyses the long-term soil thermal regime of a warm-based glacial front site located at Low Head, King George Island. The monitoring system consists of soil temperature probes connected to a datalogger that recorded data at hourly intervals. We calculated the thawing days (TD), freezing days (FD), number of isothermal days (ID), number of freeze-thaw days (FTD), thawing degree days (TDD), freezing degree days (FDD), and the apparent thermal diffusivity (ATD). The results indicate that active layer thermal regime at Low Head is similar to other periglacial environments from Maritime Antarctica, with differences associated with the influence from the nearby warm-based glacier. Surface temperatures show greater variations during the summer resulting in frequent freeze and thaw cycles, mainly (1 cm and 10 cm). The temperature profile during the studied period indicates that the active layer thickness reached a maximum of 106 cm on February 7th 2015. Soil temperature buffering was limited by the low snow cover, low soil moisture, and absence of vegetation. Based on the high interannual variability detected during the five years monitoring run, we stress that longer monitoring periods are necessary for a more detailed knowledge on how permafrost respond to climate changes in this rapidly warming zone.

The QTP (Qinghai-Tibet Plateau) holds the greatest concentration of high-elevation inland lakes in the world, and most of these lakes are located in the QTP endorheic basin. Accelerated lake expansion in the endorheic basin since 2000 has been confirmed by many studies, but there is disagreement as to which components of the water balance explain most of the lake expansion. In this paper, based on Landsat images, meteorological data, glacier data and permafrost monitoring data, we analyzed the spatial–temporal changes in lake area and further explored the driving factors behind rapid lake expansion in different zones in the endorheic basin. The results suggested that the spatial pattern of trends in lake area in the endorheic basin from 2000 to 2017 showed a southwest-northeast transition from contracting to slightly expanding to rapidly expanding. More importantly, the dramatic lake expansion observed in most regions was statistically significant (0.01 ~ 26.29 km2/yr). Although retreating glaciers may have contributed to lake growth, this can not fully explain the recent lake expansion. We find that increasing precipitation was the primary driver behind lake expansion, and that permafrost degradation accelerated lake expansion. Lakes on the northern slope of the Gangdise Mountains, fed by the most rapidly retreating glaciers, were relatively stable or even contracted. In contrast, most of the non-glacier-fed lakes in the Hoh Xil region and the central endorheic basin nevertheless experienced significant expansion and slight expansion, respectively, which were mainly attributed to the greatest increase in AP (annual precipitation). Remarkable lake expansion was found in the continuous permafrost zone. The increasing ALT (active layer thickness) and soil temperature of permafrost resulted in an increase in meltwater from ground ice, the partial release of soil moisture and an amount of unfrozen water content, which has contributed to supply lakes and accelerated lake expansion.

The study reports the results of a geochemical survey in a coastal area of northern Italy with focus on the distribution of chemical elements in near surface sediments as result of both sediment origin and anthropogenic activities. In addition to emphasizing the source-to-sink element dynamics in the area, the main purpose of this paper is to ascertain if anthropic presence could have altered the composition of near surface sediments in urban and industrial areas. We considered 173 sampling sites, and collected soil material from a depth of 90–110 cm. Major and trace elements assessment on milled 2 mm fraction was conducted using WDXRF for Al, As, Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, Si, Sr, Th, Ti, V, Y, Zn and Zr. In addition, Loss On Ignition (LOI) was determined. Principal component analysis (PCA) and cluster analysis (CA) were performed for data interpretation. The distribution of element concentration is heavily related to sediment origin. The major presence of Al, Fe, K, LOI, Mg, Nb, Rb and V characterizes alluvial plain sediments. These materials of Apenninic origin have a finer texture and a major presence of carbonates in respect to the other sediments of the area. Coastal sediments display a general wider range of variation in element concentrations (i.e. Al, Ca, Cr, K, Mg, Mn, P, Si, Ti and Zr) due to a dual origin. In particular, the greater Cr, Mn and Zr content is related to sediments enriched by heavy minerals (e.g. garnet, chromite, zircon) of Alpine origin, while the lesser concentrations trace back to Apenninic origin. Near surface sediments of urban and industrial areas always contain higher Cu, Pb and Zn concentrations with respect to the same sediments not impacted by urban and industrial settlements. This is likely a consequence of the movement of materials made by men over the last 2000 years. These results suggest that the adopted depth of sampling for the calculation of background values might need to be increased in urban and industrial areas to reach unaltered near surface sediments.

The indeterminate channel problem arises from uncertainty in finding a closure relation for alluvial channels created by self-organizing erosional and depositional processes. Extremal hypotheses have been proposed as one potential approach to closing the system of governing equations for alluvial channels. Many different extremal hypotheses have been presented, but no substantive evidence has been developed to select which hypothesis may be most appropriate for natural alluvial river systems. This paper evaluates the ability of ten extremal hypotheses to identify dynamic equilibrium across a geomorphic gradient in the remote and undeveloped mid-latitude watershed of Rio Murta, Chile. This study (a) introduces extremal hypotheses, (b) describes the field site and geomorphic conditions, and (c) examines which extremal hypotheses are supported by the field data in identifying the evolutionary trend toward dynamic-equilibrium. The extremal hypotheses that identified dynamic equilibrium within the geomorphic gradient in the field are: (1) minimum kinetic energy, (2) minimum specific stream power, (3) maximum friction factor, and (4) maximum total friction factor, which collectively support minimizing kinetic energy of the system.

The aim of this paper is to assess the impacts of projected climate change on a Mediterranean catchment, and to analyze the effects of a suite of representative land use practices as an adaptation tool to reduce climate change-driven erosion and hydrologic extremes. Relevant climatic variables from the ERA-Interim global atmospheric reanalysis of the European Centre for Medium-Range Weather Forecasts (ECMWF) were downscaled for the study area, and perturbed with the anomalies of 23 global circulation models for three emission scenarios (B1, A1B and A2). Both a projected daily rainfall time series for the period 2010-2100, and a single precipitation event with a one-hundred year return period were used to assess the impact of climate change. The downscaled data were fed into a distributed hydro-sedimentary model (TETIS) with five land use configurations representative of future demographic tendencies, geographical characteristics and land management policies (e.g. European Union CAP). The projected changes showed a general decrease in runoff and sediment production by the end of the century regardless of land use configuration. Sediment production showed a positive relationship with an increase in agricultural land and a decrease in natural land under present day agricultural management. According to our simulations, some conservation practices in agriculture can effectively reduce net erosion while maintaining agricultural production. As such, they can play a critical role as an adaptation tool to reduce climate change impacts in the 21st century., This study was funded by the Spanish Ministry of Economy and Competitiveness through the research projects CLARIES (ref. CGL2011-29176) and PALEOMED (CGL2014-58127-C3-1-R).

This paper aims at a better understanding of the role of soil characteristics in piping activity in a mountainous area under a temperate climate. The recognition of favourable soil properties is widely described in badlands with dispersive materials, and in loess-covered hilly regions. In other regions – without dispersive materials or without extensive loess deposits – piping conditions draw hardly any attention. The survey was carried out in the Tyskowa catchment, in the Bieszczady Mts. (Eastern Carpathians). We focused on soil characteristics that can impact erodibility, including texture, structure, consistence, porosity, and bulk density. These characteristics, as well as selected chemical properties (pH, exchangeable cations, and sodium absorption ratio — SAR), were studied in detail for 4 soil profiles with a different position in relation to collapsed pipes (CPs): on a slope with abundant CPs and on one lacking CPs. We tested a hypothesis that soil properties control the occurrence of pipes, and we checked if there is any difference in soil properties on slopes with and without CPs. Moreover, we compared soil profiles within the slope with CPs. Additionally, detailed geomorphological mapping of piping forms was carried out in the selected catchment in order to determine the depth of the pipe formation. No clear difference in soil characteristics was observed between the slope with high piping activity and the one without it with Cambisols occupying both sites. The soils exhibit a large content of silt, which potentially enhances piping. The chemical properties do not differ among the analysed soils. However, the profiles at the site above CPs (with potential piping) and in the sinkhole are characterized by intense biological activity, the development of soil structure in deeper horizons (angular and subangular blocky structure down to 90–105 cm), high porosity, and low bulk density. To summarize, it is the combination of biological activity and soil properties (silty texture, well-developed soil structure, low bulk density, and high porosity) that determines the formation of pipes in the study area. Combining all the results from the soil profiles and the depth of pipes indicates that pipes develop on the boundary of B and C soil horizons, and the mean depth of pipe formation is almost 0.80 m with the maximum of 1.55 m.

Objectives Under the background of global climate change, variations in streamflow and sediment discharge in the Yellow River would continue with intensified human activities and changes in the ecological environment. To harness the Yellow River, analyzing the degrees of change and the reasons for the streamflow and sediment discharge, as well as predicting the future trends, are urgently needed. Methods In this paper, the non-parametric Mann–Kendall test, Sen's estimator of slope, Pettitt's test and wavelet transform were applied to detect the trends, the magnitude of the trends and the abrupt changes and periodic variation in streamflow and suspended sediment discharge at eight hydrological stations from 1950 to 2013 along the mainstream of the Yellow River. Results Over the past 64 years (1950–2013), the spatial distribution of the annual average streamflow was of the “M” type, and the annual average suspended sediment discharge had a parabolic curve shape along the mainstream of the Yellow River. The temporal variation showed a distinct decreasing trend in streamflow since the 1990s and in suspended sediment discharge since the 1980s. Many cycles of oscillations occurred in the streamflow and suspended sediment discharge variation, leading to an alternate change in the wet/dry periods and the high/low sediment discharge periods. Conclusions In various regions of the Yellow River Basin since the 1970s, climate changes contributed reductions of 17.0–45.0% and 12.2–50.3% for streamflow and suspended sediment discharge, respectively, whereas human activities contributed reductions of 55.0–83.0% and 49.7–87.8%. Therefore, human activities were the major causes of the significant decline in the streamflow and the suspended sediment discharge of the Yellow River over the past six decades. Reasonable and possible measures should be taken to achieve water resources optimization and configuration and to promote watershed management and sustainability in the regions of the Yellow River Basin.

Preparation of landslide susceptibility map is the first step for landslide hazard mitigation and risk assessment. The main aim of this study is to explore potential applications of two new models such as two-class Kernel Logistic Regression (KLR) and Alternating Decision Tree (ADT) for landslide susceptibility mapping at the Yihuang area (China). The ADT has not been used in landslide susceptibility modeling and this paper attempts a novel application of this technique. For the purpose of comparison, a conventional method of Support Vector Machines (SVM) which has been widely used in the literature was included and their results were assessed. At first, a landslide inventory map with 187 landslide locations for the study area was constructed from various sources. Landslide locations were then spatially randomly split in a ratio of 70/30 for building landslide models and for the model validation. Then a spatial database with a total of fourteen landslide conditioning factors was prepared, including slope, aspect, altitude, topographic wetness index (TWI), stream power index (SPI), sediment transport index (STI), plan curvature, landuse, normalized difference vegetation index (NDVI), lithology, distance to faults, distance to rivers, distance to roads, and rainfall. Using the KLR, the SVM, and the ADT, three landslide susceptibility models were constructed using the training dataset. The three resulting models were validated and compared using the receive operating characteristic (ROC), Kappa index, and five statistical evaluation measures. In addition, pairwise comparisons of the area under the ROC curve were carried out to assess if there are significant differences on the overall performance of the three models. The goodness-of-fits are 92.5% (the KLR model), 88.8% (the SVM model), and 95.7% (the ADT model). The prediction capabilities are 81.1%, 84.2%, and 93.3% for the KLR, the SVM, and the ADT models, respectively. The result shows that the ADT model yielded better overall performance and accurate results than the KLR and SVM models. The KLR model considered slightly better than SVM model in terms of the positive prediction values. The ADT and KLR are the two promising data mining techniques which might be considered to use in landslide susceptibility mapping. The results from this study may be useful for landuse planning and decision making in landslide prone areas.

Many regions around the world experienced abrupt climate change with far-reaching societal and environmental effects at ca. 4.2 cal. ka BP. As one of the most distinct climatic events of the last 11.7 ka, it has been used to establish the formal boundary between the mid- and late-Holocene. Although the 4.2 ka event was not pronounced in East-Central Europe, its exact impact on the area has yet to be evaluated. The aim of this paper is twofold: (1) to reconstruct the functioning of the selected lake and terrestrial ecosystems from northern Poland around the time of the 4.2 ka event, and (2) to disentangle the drivers of the recorded environmental changes (local factors vs. climate impact). We studied the sedimentary record of Lake Spore, focusing on the period between 3.8 and 4.5 cal. ka BP using numerous biotic and abiotic proxies, such as chironomids, cladocerans, pollen and spores, δ13Corg, δ15Norg, δ18Ocarb, δ13Ccarb, TOC/N, Fe, S, LOI550, and LOI950. The chironomid-derived reconstruction of mean July air temperature did not change during the 4.2 ka event. Pollen accumulation rate (PAR) data showed lower pollen production of some tree taxa during the period 4.0–4.25 cal. ka BP that is consistent with low PARs recorded for the corresponding period in the sediments of nearby (~75 km) Lake Suminko. This change might have occurred due to either regional-scale forest disturbance or cooler winters resulting from an exceptionally strong Siberian High during the 4.2 ka event. Distinct peaks of Fe and δ13Ccarb at 4.2 cal. ka BP likely record a pulse of podzolization. Although soil transformation processes were common in East-Central Europe after ca. 5 cal. ka BP due to general climate cooling, they could have been enhanced at Lake Spore during the 4.2 ka event, if winters were more severe. The δ13Corg, δ15Norg, TOC/N and δ18Ocarb records point to a water level rise after 4.2 cal. ka BP that most likely resulted from soil transformation in the catchment, not a change in effective precipitation. The composition of the terrestrial vegetation and the lake fauna and flora remained largely unaffected by the 4.2 ka event.

International audience; Landslides are a common type of natural disaster that brings great threats to the human lives and economic development around the world, especially in the Chinese Loess Plateau. Longxian County (Shaanxi Province, China), a landslide-prone area located in the southwest part of the Loess Plateau, was selected as the study area. The main purpose of this paper is to map landslide susceptibility using Alternating decision tree (ADTree) as well as GIS-based new ensemble techniques involving ADTree with bootstrap aggregation (Bagging) and ADTree with adaptive boosting (AdaBoost). Initially, a landslide inventory map was prepared with 171 determined historical landslides events in the study area, 120 landslides (70%) were randomly selected for training dataset and the remaining 51 landslides (30%) were used for validation dataset. Subsequently, eleven landslide conditioning factors were considered in the landslide susceptibility mapping. Then, an optimization operation on selection of landslide conditioning factors was performed using correlation attribute evaluation method and Spearman’s rank correlation coefficient. Afterwards, landslide susceptibility maps were generated with the three models. Finally, receiver operating characteristic (ROC) curve, area under the ROC curve (AUC) and statistical measures were applied to evaluate and validate the performance of the models. The results show success rates of the ADTree model, the ADTree with Bagging (ADTree-Bagging) model and the ADTree with AdaBoost (ADTree-AdaBoost) model were 0.872, 0.917, and 0.984, respectively, while prediction rates of the three models were 0.696, 0.752 and 0.787, respectively. In sum, the two ensemble models proposed prohibited better performance than the ADTree model did, and the ADTree-AdaBoost model was selected as the best model in the study. Hence, ensemble techniques can provide new and promising methods for spatial prediction and zonation of landslide susceptibility.

Cultural landscapes are the result of human societies interacting with their environment, which is reflected in the onset and evolution of social practices such as settlement and agricultural production. This paper discusses the results of a transdisciplinary research program carried out on the vineyard landscape of the Rioja Alavesa district, one of the main wine-producing regions of Spain, focusing on the deserted village of Torrentejo (Basque Country, Spain). The study of archival records, combined with extensive archaeological survey and excavation, as well as the intensive analysis of geoarchaeological core samples, permitted the reconstruction of a long sequence of human settlement and agricultural practices extending over ~4000 years. The oldest documented records refer to a Chalcolithic occupation, developed on a buried gypsisol and possibly related to the climatic event at 4.2 ka BP. After a long hiatus, four phases of landscape transformation were documented above this Chalcolithic occupation: (1) the formation of a nucleated village in the Early Middle Ages, represented by the construction of a terraced agricultural landscape, and its passage under the control of different seigneurial powers over the High Middle Ages; (2) the abandonment of the village during the Late Middle Ages and the subsequent concentration of settlement in the charted town of Bastida; (3) a complete reorganisation and expansion of the local terraced systems in the 18th–19th centuries, in a context of specialisation and commercialisation of agricultural production; and (4) present-day mechanisation and capitalisation. These results therefore offer an interesting overview on the complexity and diversity of the historical trends that lie beneath the vineyard landscape of Torrentejo, proving the value of interdisciplinary research approaches for the investigation of the role of human settlement and agriculture in the formation and evolution of agricultural landscapes., This research was supported by the project “Peasant agency and social complexity in north-western Iberia in the medieval period” (Spanish Ministry of Economy, Industry and Competitiveness AEI/FEDER UE HAR2016-76094-C4-2R), the Research Group on Medieval Archaeology, Heritage and Cultural Landscapes (Government of the Basque Country, IT1193-19) and the Group of Rural Studies (Associated Unit UPV/EHU-CSIC).

This paper describes the application of the Italian chabazite-rich tuff of Sorano (Grosseto) as a soil conditioner and slow nutrient fertilizer to a silty-clay soil and a sandy soil. The study was developed by means of batch and column experiments. The objectives of the study were: (1) to evaluate and compare the physical and hydraulic properties of mixtures of soil and natural zeolitite (95:5% v/v) with those of unamended soils, (2) to determine the effects of applying NH 4 + -enriched zeolitites on soils and (3) to model water and solutes movement in two different scenarios, with and without amendment incorporation. Results of column experiments were then modelled to obtain the physical–chemical and hydraulic parameters representative of the soils amended with the NH 4 + -enriched zeolitites. Using synthetic rainwater as eluent, NH 4 + was never detected in the water phase of batches and columns; NO 3 − and PO 4 3 − were both present at high concentrations in batch tests and were leached in column elution tests. NO 3 − displayed very high concentrations at the beginning of the elution whereas PO 4 3 − showed low concentrations and retarded peaks in both amended soil columns. The rationale of the study lies in the belief that inorganic amendments, which improve the physical and hydraulic properties of soils, can lead to minimized leaching of nutrients.

This paper discusses the suitability of hand-held XRF analysis to extract palaeo-geochemical information from lacquer-peel soil sections that have been taken to document pedological information at geological and archaeological sites. This not only allows the study of sections from archaeological and geological sites that have since disappeared, but can also answer new archaeological questions on the nature of activities undertaken at such sites. Seven lacquer-peels, from different time-periods and different geogenetic backdrops, have been studied with hand-held XRF (Niton XL3t, GOLDD detector). Five of these lacquer-peels were studied to assess possible interference from mounting materials (glues, textiles and framing boards) used. Four of these lacquer-peels were studied for their palaeo-geochemical information. These lacquer-peels were taken from prehistoric agricultural plots and settlement sites, ranging in age from the Neolithic to the Iron Age. Values for Si, K, Al, Fe, Ti, Sr, Zr and Rb reflect lithogenetic and pedological processes. The contents of S, Ca and P were used as a proxy for anthropogenic influence. The lacquer-peels provided consistent and reliable geochemical readings with the hand-held XRF. Observed correspondence between pedological predictions, archaeological hypotheses and the measured results testifies to the suitability of hand-held XRF for palaeo-geochemical characterization. Interference from the primarily organic fixing- and mounting-agents used was absent. Consequently, hand-held XRF analysis allows extraction of palaeo-geochemical information from lacquer-peel soil sections, which opens-up a new potential data-set for reconstructing past pollution and to geochemically re-assess geological and archaeological sites from existent lacquer peels — adding a geochemical dimension to lacquer-peels of pedological, archaeological and geological sites.

This paper investigates soil stratigraphy of lynchets in sloping lands in eastern Belgium, and rates of their development by comparison to tillage translocation by non-mechanised agriculture. In Belgium, detailed topographical surveys and augerings were carried out at three sites that were under cropland till 1900–1950. Rates and diffusion constants of current non-mechanised tillage erosion were monitored in Ethiopia using tracers, and by precise surveys of tillage steps of known ages. The lynchets in Belgium consist of colluvium that was removed at the upper border of previously farmed plots. Repeated tillage with animal drawn implements results in soil translocation fluxes to the lower plot borders in the order of 11 to 91 kg m − 1 year − 1 (for slope gradients between 0.03 and 0.35 m m − 1 ). The studied lynchets in eastern Belgium would have required cropping agriculture for a total of 217–585 years on steep, and 1037–1867 years on gentle slopes. The establishment of lynchets hence took place without any deliberate action of digging, but due to repeated tillage, even with simple implements, and water erosion. Calculated time spans of tillage indicate that some parts of the study area had already been under cultivation during the Gallo-Roman period, others since the Middle Ages.

Extreme events disturb the development paths of geomorphological systems. The effect of such events on relief tends to persist for long periods of time and affects the future development of such systems. This paper focuses on changes in middle mountain valleys associated with an extreme hydro-geomorphological event that occurred in the Western Tatra Mountains (Polish Carpathian Mountains) in June of 2007. The geomorphological effects were mapped and an analysis of valley-bottom deposits and dendro-geomorphological data on tree roots and stems was used to identify patterns in the geomorphological transformation taking place during such events. In addition, the organic material obtained from fans was dated by means of carbon-14 dating. The effects of previous extreme events in the study area and their geomorphological outcomes were compared. Four main valley section types were identified in the valley longitudinal profile. Unevenly aged (from 14C 390 ± 30 years YBP (1441–1631 cal AD) to 14C 3760 ± 70 YBP (4318–3962 cal BP)) organic material was revealed at different depths of each studied fan. A complex structure with alternating layers of fine and coarse material from the analysed fans was identified. The colluvial-alluvial structure of fans suggests that extreme high-energy events did occur more than once per century during the Holocene. This type of fan structure can be referred to as a patchwork. In the study area, rainfall with high energy potential occurs once in every 6–9 years and extreme hydro-geomorphological events occur every 15 years. This type of extreme event may not be exceptional in the history of middle mountain areas.