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Despite a long‐term human impact, Central and Eastern Europe exhibit patches of steppe ecosystems having the highest plant species diversity worldwide. These unique ecosystems have persisted over millennia even though the local climatic conditions would support the formation of a closed forest. Several sources of disturbances have contributed to the persistence of the forest‐steppe landscape such as grazing, fire events and human impact. These disturbances have been recorded in local erosion rates. To gain a deeper understanding of the soil dynamics we aimed at deciphering the long‐ and short‐term erosion rates and the age of the soil mantle. The steppes in Transylvania, Romania, were studied to find evidence of a Holocene continuity of grasslands. Long‐term (millennia) average erosion rates were determined using meteoric 10Be in soils and in situ 10Be of rock outcrops (scarp). Long‐term rates were also estimated by the percolation theory. Short‐term (last few decades) erosion rates were obtained from 239+240Pu in soils. The soils started to form prior to the Last Glacial Maximum, probably during the Eemian Interglacial. The average, long‐term erosion rates varied between 0.18 and 0.63 t ha−1 yr−1. These rates are slightly elevated compared to expected soil erosion rates. The soils of the Transylvanian Plain formed over a long period and reached a quasi‐steady state (soil production equals denudation) that contributed to the maintenance of a biodiversity‐rich forest‐steppe landscape. The slightly elevated erosion rates are an effect of factors that contributed to the Holocene continuity (fire, grazing) and indicate open rather than a forested character of the landscape during soil development. During the last few decades, the erosion rates increased by a factor of 5–10, with values in the range of 1.31–4.05 t ha−1 yr−1. These large differences are caused by changes in human management of the soils. The biodiversity‐rich forest‐steppe landscapes are now under threat. [ABSTRACT FROM AUTHOR]

Isotopes of meteoric 10Be, 137Cs, 239+240Pu have been proposed as a soil redistribution tracer and applied worldwide as an alternative method to classical field-related techniques (e.g., sediment traps). Meteoric 10Be provides information about long-term soil redistribution rates (millennia), while 137Cs and 239+240Pu give medium-term rates (decades). A significant progress in developing new models and approaches for the calculation of erosion rates has been made; thus, we provide a global review (n = 59) of research articles to present these three isotopes (meteoric 10Be, 239+240Pu and 137Cs) as soil erosion markers in different environments and under different land-use types. Understanding the dynamics and behaviours of isotopes in the soil environment is crucial to determine their usefulness as soil erosion tracers; thus, we discuss the chemical–physical behaviour of meteoric 10Be, 137Cs and 239+240Pu in soils. The application of these isotopes sometimes has strong limitations, and we give suggestions on how to overcome them or how to adapt them to a given situation. This review also shows where these isotopic methods can potentially be applied in the future. A lack in knowledge about soil redistribution rates exists particularly in loess-dominated areas where the tillage system has changed or in areas with strong wind erosion. [ABSTRACT FROM AUTHOR]

Purpose: Spatial and temporal patterns of past erosional events are a useful and needed information to explain observed soil patterns in different landscapes. Soil thickness reflects the overall expression of pedogenesis and erosion. Forested soils of Northern Germany exhibit varying soil thicknesses with thin soils on crest positions and buried soils at the footslope. The aim of this study is to reconstruct the complex soil mass redistribution and soil patterns of this forested area due to different periods of erosion and stability. Methods: We explored the explanatory power of both 10Be (in situ and meteoric) on a hillslope and we 14C-dated buried horizons at different depths. Results: The 10Be depth profiles did not show an exponential decrease with depth. They had a 'bulge' shape indicating clay translocation and interaction with oxyhydroxydes (meteoric 10Be), bioturbation and soil mass redistribution (in situ 10Be). The combined application of both 10Be and 14C dating revealed progressive and regressive phases of soil evolution. Although Melzower Forest is protected (same vegetation) since the past 250 years, both 10Be clearly indicated major soil mass redistribution along the investigated catena. Conclusion: A strong erosion impulse must have occurred between 4.5 and 6.8 kyr BP indicating an earlier human impact on soil erosion than previously postulated (~ 3 kyr earlier). Our findings correlate in fact with the first settlements reported for this region (~ 6.8 kyr BP) and show their immediate effect on soils. The overall soil redistribution rates in this forest are surprisingly similar to those obtained from a nearby agricultural area. [ABSTRACT FROM AUTHOR]

High mountainous areas are geomorphologically active environments which are strongly shaped by redistribution of sediments and soils. With the projected climate warming in the twenty‐first century and the continued retreat of glaciers, the area of newly exposed, highly erodible sediments and soils will increase. This presents a need to better understand and quantify erosion processes in young mountainous soils, as an increase in erodibility could threaten human infrastructure (i.e. hydroelectric power, tourist installations and settlements). While soil development is increasingly well understood and quantified, a coupling to soil erosion rates is still missing. The aim of this study was, therefore, to assess how soil erosion rates change with surface age. We investigated two moraine chronosequences in the Swiss Alps: one in the siliceous periglacial area of Steingletscher (Sustenpass), with soils ranging from 30 a to 10 ka, and the other in the calcareous periglacial area of Griessgletscher (Klausenpass) with surfaces ranging from age of 110 a to 13.5 ka. We quantified the erosion rates using the 239+240Pu fallout radionuclides and compared them to physical and chemical soil properties and the vegetation coverage. We found no significant differences between the two parent materials. At both chronosequences, the erosion rates were highest in the young soils (on average 5−10 t ha‐1 a‐1 soil loss). Erosion rates decreased markedly after 3−5 ka of soil development (on average 1−2.5 t ha‐1 a‐1 soil loss) to reach a more or less stable situation after 10−14 ka (on average 0.3–2 t ha‐1 a‐1). Climate change not only causes glacier retreat, but also increased sediment dynamics. Depending on the relief and vegetational development, it takes up to at least 10 ka to reach soil stability. The establishment of a closed vegetation cover with dense root networks seems to be the controlling factor in the reduction of soil erodibility. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Tree uprooting may distinctly affect landscape dynamics and slope denudation. Little is known, however, about the corresponding soil redistribution rates (erosion and accumulation) on either a long‐term (millennia; 10Be) or a short‐term (decades; 239+240Pu) scale. We determined these rates in a well‐investigated forest reserve (Zofinsky primeval forest, Czech Republic) using complementary techniques: nuclides in soils and tors to derive short‐ to long‐term rates and monitoring data (43 years) of repeated tree censuses using tree uprooting data. Temporal trends of soil erosion rates were obtained by dating the timing of exhumation (10Be) of tors. The average long‐term denudation rates were about 30–40 t km−2 yr−1. It seems that these rates varied over time with probably a maximum during the Pleistocene/Holocene transition (58–91 t km−2 yr−1). 239+240Pu activities in the soils identified soil redistribution rates of 50 to >100 t km−2 yr−1 for the last decades and agree with results from the tree uprooting monitoring (<92 t km−2 yr−1). In‐situ 10Be in soils gave similar denudation rates (58–76 t km−2 yr−1). Meteoric 10Be provided a mean residence time of a soil particle of 33–100 ka supporting the measured average long‐term erosion rates. Soil aggregates indicated stable physical conditions meaning that soil mass redistribution occurs only sporadically. It seems that the main driving factors of denudation changed over time. An erosion peak at the Pleistocene/Holocene transition (climate change) seems likely but needs further proof. Over the last few millennia, tree uprooting seems the main driver of soil erosion. [ABSTRACT FROM AUTHOR]

How soil erosion rates evolved over the last about 100 ka and how they relate to environmental and climate variability is largely unknown. This is due to a lack of suitable archives that help to trace this evolution. We determined in situ cosmogenic beryllium‐10 (10Be) along vertical landforms (tors, boulders and scarps) on the Sila Massif to unravel their local exhumation patterns to develop a surface denudation model over millennia. Due to the physical resistance of tors, their rate of exhumation may be used to derive surface and, thus, soil denudation rates over time. We derived soil denudation rates that varied in the range 0–0.40 mm yr‐1. The investigated boulders, however, appear to have experienced repositioning processes about ~20–25 ka bp and were therefore a less reliable archive. The scarps of the Sila upland showed a rapid bedrock exposure within the last 8–15 ka. Overall, the denudation rates increased steadily after 75 ka bp but remained low until about 17 ka bp. The exhumation rates indicate a denudation pulse that occurred about 17–5 ka bp. Since then the rates have continuously decreased. We identify three key factors for these developments – climate, topography and vegetation. Between 75 and 17 ka bp, climate was colder and drier than today. The rapid changes towards warmer and humid conditions at the Pleistocene–Holocene transition apparently increased denudation rates. A denser vegetation cover with time counteracted denudation. Topography also determined the extent of denudation rates in the upland regime. On slopes, denudation rates were generally higher than on planar surfaces. By determining the exhumation rates of tors and scarps, soil erosion rates could be determined over long timescales and be related to topography and particularly to climate. This is key for understanding geomorphic dynamics under current environmental settings and future climate change. © 2019 John Wiley & Sons, Ltd. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Two principal groups of processes shape mass fluxes from and into a soil: vertical profile development and lateral soil redistribution. Periods having predominantly progressive soil forming processes (soil profile development) alternate with periods having predominantly regressive processes (erosion). As a result, short‐term soil redistribution – years to decades – can differ substantially from long‐term soil redistribution; i.e. centuries to millennia. However, the quantification of these processes is difficult and consequently their rates are poorly understood. To assess the competing roles of erosion and deposition we determined short‐ and long‐term soil redistribution rates in a formerly glaciated area of the Uckermark, northeast Germany. We compared short‐term erosion or accumulation rates using plutonium‐239 and ‐240 (239+240Pu) and long‐term rates using both in situ and meteoric cosmogenic beryllium‐10 (10Be). Three characteristic process domains have been analysed in detail: a flat landscape position having no erosion/deposition, an erosion‐dominated mid‐slope, and a deposition‐dominated lower‐slope site. We show that the short‐term mass erosion and accumulation rates are about one order of magnitude higher than long‐term redistribution rates. Both, in situ and meteoric 10Be provide comparable results. Depth functions, and therefore not only an average value of the topsoil, give the most meaningful rates. The long‐term soil redistribution rates were in the range of −2.1 t ha‐1 yr‐1 (erosion) and +0.26 t ha‐1 yr‐1 (accumulation) whereas the short‐term erosion rates indicated strong erosion of up to 25 t ha‐1 yr‐1 and accumulation of 7.6 t ha‐1 yr‐1. Our multi‐isotope method identifies periods of erosion and deposition, confirming the 'time‐split approach' of distinct different phases (progressive/regressive) in soil evolution. With such an approach, temporally‐changing processes can be disentangled, which allows the identification of both the dimensions of and the increase in soil erosion due to human influence. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The importance of gradual erosion relative to landsliding depends predominantly on the slope angle. One factor of critical influence in landsliding along with slope angle and slope shape is the soil depth. Understanding soil depth development on steep topography is fundamental for understanding and predicting the occurrence of landsliding at threshold landscapes. We develop a model to predict soil depth that addresses both threshold and gradual processes. If erosion is a gradual process, soil depth increases until the soil production rate no longer exceeds the erosion rate, and steady state is reached. The predicted soil depth (x) is proportional to the ratio of the infiltration to the erosion rate. Identifying a predictive result for erosion as a function of slope angle (S) allows a test of both the erosion and soil production models with field observations. The same theoretical approach to soil production should be applicable when the principal erosion process is shallow landsliding. After landslides, soil recovery initially follows our predicted power law increase in time, though with increasing time background erosion processes become important. At a time equal to a landslide recurrence interval, the soil depth can exceed the steady state depth by as much as a factor 2. By comparing predicted and observed x(S) results, we show that the accessed result for erosion as a function of slope angle is accurate. Soils deeper than the depth predicted at the landslide recurrence interval are beyond the stability limit. This result suggests an important practical relevance of the new soil production function. Key Points: Steady state soil depth is proportional to the infiltration, but inversely proportional to the erosion rate, when erosion is gradualA quasi‐universal prediction of soil depth as a function of slope angle is generated for gradual erosion and landslidingWhile mean slope depths for gradual erosion and landsliding are similar, for the same total erosion rate, greater depths can be achieved in the latter [ABSTRACT FROM AUTHOR]

Landscapes and soils evolve in non‐linear ways over millennia. Current knowledge is incomplete as only average denudation (or erosion) rates are normally estimated, neglecting the temporal discontinuities of these processes. The determination of regressive and progressive phases of soil evolution is important to our understanding of how soils and landscapes respond to environmental changes. The Sila Massif (Italy) provides a well‐defined geomorphological and geological setting to unravel temporal variations in soil redistribution rates. We used a combination of in situ cosmogenic radionuclide measurements (10Be) along tor (residual rock) height profiles, coupled with fallout radionuclides (239+240Pu) in soils, to model soil denudation rates over the last 100 ka. We measured rates prior to the Last Glacial Maximum (LGM) of ≤30 t km−2 yr−1 (~0.036 mm yr−1). Following the LGM, during the transition from the Pleistocene to the Holocene, these rates increased to ~150–200 t km−2 yr−1 and appeared to be above soil production rates, causing regressive soil evolution. For the last ~50 years, we even describe erosion rates of ≥1,000 t km−2 yr−1 (~1.23 mm yr−1) and consider human impact as the decisive factor for this development. Consequently, the natural soil production rates cannot cope with the current erosion rates. Thus, a distinct regressive phase of soil formation exists, which will give rise to shallowing of soils over time. Overall, our multimethod approach traced denudation and erosion histories over geologic and human timescales and made a new archive to soil science and geomorphology accessible. [ABSTRACT FROM AUTHOR]

Abstract: Soils in mountainous areas are often polygenetic, developed in slope covers that relate to glacial and periglacial activities of the Pleistocene and Holocene and reflect climatic variations. Landscape development during the Holocene may have been influenced by erosion/solifluction that often started after the Holocene climatic optimum. To trace back soil evolution and its timing, we applied a multi‐methodological approach. This approach helped us to outline scenario of soil transformation. According to our results, some aeolian input must have occurred in the late Pleistocene. During that time and the early Holocene, the soils most likely had features of Cryosols or Leptosols. Physico‐chemical and mineralogical analyses have indicated that the material was denudated (between late Boreal to the Atlantic) from the ridge and upper‐slope positions forming a colluvium at mid‐slope positions. Later, during the Sub‐Boreal, mass wasting of the remains of silt material deposited at the end of the Pleistocene age on the ridge top seems to have occurred. In addition, the cool and moist conditions caused the deposition of a colluvium at the lower‐slope positions. The next phase was characterized by the transformation of Leptosols/Cambisols into Podzols at upper‐slope or shoulder positions and to Albic Cambisols at mid‐slope positions. During the Sub‐Boreal period, Stagnosols started to form at the lower part of the slope catena. Overall, the highest erosion rates were calculated at the upper‐slope position and the lowest rates at mid‐slope sites. Berylium‐10 (10Be) data showed that the Bs, BC/C were covered during the Holocene by a colluvium with a different geological composition which complicated the calculation of erosion or accumulation rates. The interpretation of erosion and accumulation rates in such multi‐layered materials may, therefore, be hampered. However, the multi‐methodological reconstruction we applied shed light on the soil and landscape evolution of the eastern Karkonosze Mountains. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Spatially discontinuous permafrost conditions frequently occur in the European Alps. How soils under such conditions have evolved and how they may react to climate warming is largely unknown. This study focuses on the comparison of nearby soils that are characterised by the presence or absence of permafrost (active-layer thickness: 2-3 m) in the alpine (tundra) and subalpine (forest) range of the Eastern Swiss Alps using a multi-method (geochemical and mineralogical) approach. Moreover, a new non-steady-state concept was applied to determine rates of chemical weathering, soil erosion, soil formation, soil denudation, and soil production. Long-term chemical weathering rates, soil formation and erosion rates were assessed by using immobile elements, fine-earth stocks and meteoric 10Be. In addition, the weathering index (K + Ca)/Ti, the amount of Fe- and Al-oxyhydroxides and clay minerals characteristics were considered. All methods indicated that the differences between permafrost-affected and non-permafrost-affected soils were small. Furthermore, the soils did not uniformly differ in their weathering behaviour. A tendency towards less intense weathering in soils that were affected by permafrost was noted: at most sites, weathering rates, the proportion of oxyhydroxides and the weathering stage of clay minerals were lower in permafrost soils. In part, erosion rates were higher at the permafrost sites and accounted for 79-97% of the denudation rates. In general, soil formation rates (8.8-86.7 t/km2/yr) were in the expected range for Alpine soils. Independent of permafrost conditions, it seems that the local microenvironment (particularly vegetation and subsequently soil organic matter) has strongly influenced denudation rates. As the climate has varied since the beginning of soil evolution, the conditions for soil formation and weathering were not stable over time. Soil evolution in high Alpine settings is complex owing to, among others, spatio-temporal variations of permafrost conditions and thus climate. This makes predictions of future behaviour very difficult. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: A toposequence of Holocene soils located between 1100–2400 m asl in the Italian Alps served as the basis for the following analyses: the weathering of limestone and dolomite, the calculation of mass balances, understanding the formation of pedogenic Fe and Al, the determination of soil mineral and clay mineral reactions and transformation and the measurement of accumulation and stabilisation mechanisms of soil organic matter. Leaching of carbonates is most intense at the lower elevations, although calcite and dolomite have a higher solubility at low temperatures. The pCO2 in the soil is higher at lower elevations and weathering is driven mainly by carbonic acids. At higher elevations, organic acids appear to determine the mineral transformations and weathering reactions to a greater extent. This suggests that two very different weathering regimes (carbonic and organic acid weathering) exist along the toposequence. The transformation of mica into vermiculite is the main process in both the clay and fine-earth fraction. Weathering of silicate minerals started even before the carbonates had been completely removed from the soils. The transformation mechanisms of silicate minerals in the A and O horizon at higher elevations was at least as intensive as that at the climatically warmer sites. The neoformation of pedogenetic clays at climatically cooler sites was slightly greater than that at the warmer sites. However, the formation rate of secondary Fe and Al phases was more pronounced at lower elevation, which means that this process seemed to be driven dominantly by carbonic acid (weathering of primary minerals). Soil organic matter (SOM) abundance in the mineral soil is nearly 15 kg/m2 at all sites and, surprisingly, no climate-driven effect could be detected. In general, the preservation and stabilisation of SOM was due to poorly crystalline Al and Fe phases and vermiculite, regardless of some variations in the composition of the parent material (varying calcite/dolomite ratio). [Copyright &y& Elsevier]

An introduction is presented in which the author discusses various reports within the issue on topics including the soil weathering rates, short- to long-term erosion processes and the contributions of soil formation and landscape modeling over time and space.

Plutonium (Pu) isotopes are attracting an increasing interest among fallout radionuclides (FRN) for their suitability as soil erosion/deposition tracer. Most of the recent studies were carried out on permanent grasslands and some in coniferous forests. One usually assumes that no erosion occurs in forested areas. However, this paradigm might be challenged because forest soils of Northern Germany in a hummocky ground moraine landscape exhibit sometimes a very shallow thickness on crest positions (Calcaric Regosols) and buried soils on slope positions (buried Ah as indicator). The question consequently is: Are these on-going or ancient processes? Therefore, a technique is needed that enables the determination of recent erosional process and a possibility to relate it to more long-term soil changes.In the present study, we measured the 239+240Pu stocks in a small, forested catchment (deciduous trees) that is characterised by a hummocky terrain including a kettle hole ("Melzower Forst"). Together with soil development depths, 239+240Pu stocks were correlated to relief parameters, e.g. the topographic position index (TPI). The TPI compares the elevation of each grid cell in a DEM with the mean elevation of a neighbourhood defined by a circle of a certain radius, in our study of 25 m.We compared the 239+240Pu stocks of fifteen different profiles and their relative erosion/accumulation rates to the TPI. Moreover, we used several mathematical models to evaluate the Pu-data and to quantify the erosion rates for the last 55 years. Our results show a very high spatial variability of the 239+240Pu stocks, from 35 to 70 Bq/m2, and no relationship to the TPI as has been demonstrated for arable land. Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240Pu stocks, giving rise to a patchy input pattern. The missing relationship between TPI and 239+240Pu stocks however demonstrated that no or negligible soil erosion has occurred during the last 55 years. As the forest has been protected for several hundreds of years, anthropogenic activities and maybe also natural events during the medieval times or earlier seemed to have caused strong erosional events which led to the soil pattern observed. [ABSTRACT FROM AUTHOR]

Young soils are typical in high-alpine regions as more and more new terrain is exposed to the atmosphere by the retreat of glaciers. Physical and chemical weathering alters the young soils' physical and chemical properties and deepens the soil profile with time. The trend of this development can be traced by using chronosequences. The high Alps are especially suitable to investigate early soil development, due to the relatively high proportion of young surface. Chemical weathering proceeds faster or slower depending on whether the parent material is siliceous or calcareous. Soil redistribution processes reshape the landscape by eroding the loose glacial sediments and by redepositing them downslope. Fallout Radionuclides (FRN) are often used to quantify such soil distribution processes. Using FRN, average erosion/accumulation rates for last few decades can be estimated. The FRNs have been deposited in soils worldwide following the numerous nuclear weapons tests which peaked in the 1960s. Plutonium (239+240Pu) is currently the most suitable element for this purpose. In contrast to 137Cs, its isotopes have a long half-life and will therefore be still available decades from now. This study pursued two goals: 1) gain data on calcareous soil evolution and 2) quantify how soil erosion differs with soil age. We investigated a soil chronosequence with moraines of different ages in the calcareous proglacial area of Griessgletscher, close to the Klausenpass in the Swiss Alps. Soil ages span from a century to about 13'000 years. We measured a variety of parameters in order to cover the most important physical and chemical processes soil development. We also measured the 239+240Pu inventories and the short-term erosion rates for each soil age. The top soil showed a strong decrease in the sand fraction from ca. 65% to 15% while clay-sized particles increased by the same factor after several millennia of soil development. Both the decarbonatization and the accumulation of organic matter may have caused this step-wise development. The isotopic composition of the Plutonium inventories showed that the input was almost exclusively from global fallout. The comparison of the short-term soil erosion rates with the soil ages showed lower erosion rates with increasing soil age. It suggests that the youngest soils are more prone to soil erosion than the older. This behavior was expected, as the more mature soils are also more vegetated soils and therefore more protected. [ABSTRACT FROM AUTHOR]

The European Alps are a geomorphologically active region and experience a number of gravity-driven hillslope processes. Soil and landscape formation in the Alps has consequently undergone several minor and major traceable changes of developmental trajectories during the Holocene. Soil development is hypothesised to be often non-linear with time and characterised by stages of progressive and regressive evolution caused by upbuilding (formation, profile deepening) and erosion (profile shallowing). Several cold and warm climate phases are identified during the Holocene but it is largely unknown which effects these might have had on slope processes. By using datable moraines ( 10 Be) and mires ( 14 C), we have constructed a temporal framework for these processes. Using the geochemical imprint of mires in the Alpine setting of the Göschener-valley of the Central Swiss Alps, we reconstructed general (mostly erosional) landscape processes for the last ca. 10 ka. As this is the type locality for the Göschener cold phase, we assumed that this phase (Göschener cold phase I and II ~ 1.5 and ~ 2.5 ka BP) should have left easily recognizable traits. After deglaciation (11–12 ka BP), soil evolution was progressive. Beginning around 8 ka BP, we detect a distinct increase in erosion here, together with a vegetation change (towards tundra vegetation) and the highest measured rates of carbon sequestration. Other phases of high geomorphic activity were recognised ca. 5–6 ka BP, 4 ka BP and, to a lesser extent, 1–3 ka ago. The cold phase at 5–6 ka BP corresponds to a less distinct change in vegetation and lessened erosion. Human impact is increasingly obvious since about 2.4 ka BP which overlaps with the Göschener cold phase. Nonetheless, erosion processes were not extraordinarily high during this period and a climate effect cannot be distinguished. We detect evidence of increasing human disturbance (regressive soil evolution) for about the last 1 ka. We also detect an increase in dust flux during the last ca. 4–5 ka, presumably due to the landscape change(s) in the Sahara during this time. [ABSTRACT FROM AUTHOR]

Trees have the ability to distinctly determine soil evolution and hillslope processes through mechanical soil disturbances such as tree uprooting. Recent findings have resulted in new biogeomorphic state transition models for old-growth forests in the temperate climate zone. The situation in tropical forests, however, is mostly unknown. Here, we focus on determining short- (decades) and long-term (millennia) soil erosion rates and the biogeomorphic role of trees on hillslope dynamics in the species-rich Wanang primeval tropical forest, Papua New Guinea. We hypothesized that trees play a significant role in hillslope dynamics on a background of powerful soil erosion dominated by abiotic factors, and that this role has potentially intensified over the last decades. The long-term soil erosion was assessed using the meteoric 10Be levels in three soil profiles along the whole depth gradient along with one natural outcrop. The recent soil erosion rate was determined using 239+240Pu levels in the uppermost soil layers. The specific role of trees in hillslope processes was evaluated based on repeated tree censuses of 65,535 tree individuals, calculating the tree mortality rate and modeling the soil volume affected by uprooted trees and by the in situ decay of the root systems of broken trees. Soil erosion was 6.25 m3 ha−1 yr−1 over the long term and indeed did increase during the last decades. While this rate was significantly affected by trees, they were not the main factor, with circa 0.95 m3 ha−1 influenced annually by uprooting, and an additional 0.61 m3 ha−1 by the in situ decay of root systems. These results reflect a forest ecosystem that is currently in the biogeomorphic stage of biotic/abiotic feedbacks. [Display omitted] • Erosion in a primary tropical forest was 6.3 m3 ha−1 yr−1 over the last thousands of years. • The erosion rate has increased in the last decades in primary tropical forest. • Individual trees significantly affected hillslope processes and pedocomplexity. • The forest ecosystem is in the biogeomorphic stage of biotic/abiotic feedbacks. [ABSTRACT FROM AUTHOR]

• Formerly glaciated area has a lower degree of soil weathering. • Non-glaciated area has high soil erosion rates (900–1700 [t km−2 yr−1]) • Meteoric 10Be indicates soil mixing. Few data are available on how soil erosion rates compare between surfaces of different ages because short-term processes often overprint the longer-term erosion signal. This study investigated the soil dynamics among two end-member sites, a formerly glaciated ('young', maximum glacial extent at 22–30 ka BP) and a non-glaciated ('old') area at the Serra da Estrela (Portugal). To disentangle soil distribution rates over different timeframes, isotopes for long-term (10Be), mid-term (δ13C) and short-term (239+240Pu) periods were applied together with principles of the percolation theory. The formerly glaciated area has soils with a lower degree of weathering and lower carbon content compared to soils of the 'old', non-glaciated area. The selected isotopes and their distribution along the soil profiles revealed temporal differences in soil mixing process. It is hypothesised that the slightly higher elevation and formerly glaciated sites experienced cryoturbation effects over a longer period, while being less active or absent for the last few decades at the older, non-glaciated soils. The average long-term (millennia) soil erosion rates correspond to the expected higher rates at the younger surface and lower rates at the older surface. Once the formerly glaciated area became ice-free, soil erosion rates were high and decreased giving rise to average long-term rates of 101–140 [t km−2 yr−1] for the older surfaces and 176–248 [t km−2 yr−1] for the younger surfaces. In addition, seasonal freeze–thaw of the soils has persisted over a long period and affected the younger soils more intensively than the older soils. The current (last decades) soil redistribution rates, however, are up to one order of magnitude higher than the millennia rates and are controlled by surface angle and vegetation cover and less by soil texture. The more undulated, non-glaciated older surface had the highest short-term (decades) soil erosion rates in the range of 900–1700 [t km−2 yr−1], exhibits degrading conditions and relatively shallow soils. The younger soils, however, showed short-term (last few decades) average soil deposition rates of ∼ 230 [t km−2 yr−1]. Human impact (bush fires, grazing) is the cause for the currently strong soil degradation at the non-glaciated area. [ABSTRACT FROM AUTHOR]

Peat and lake sediments as well as a nearby soil catena were sampled to reconstruct the environmental history of a small infilled lake basin (mire) in the central alpine foreland of Switzerland. Soil evolution is best regarded as discontinuous over time and conceptualised by ‘progressive’ or ‘regressive’ process phases. We analysed the surrounding soils and used corresponding pedosignatures in the mire sediments to characterise notable phases of erosion and deposition. We assumed that the mire sediments would reflect these phases, that elemental composition (major and minor compounds) and rare earth elements (REEs) would allow us to differentiate past processes and that progressive and regressive phases of soil development can be discerned. Although radiocarbon ages are equivocal, it appears from pollen analyses that a lake was present here by c. 45 ka BP. After the retreat of the glacier from this area following the LGM, continuous sedimentation occurred until a mire developed during Pleistocene–Holocene transition. This transition period was accompanied by more intense erosion, as characterised by chemical signatures. A stable phase developed between c. 10–5 ka BP giving rise to progressive soil evolution. Between 5 and 4 ka BP, evidence appears for several erosional phases, predominantly detectable at the margin of the mire. These erosion phases, coupled with accumulation in the mire, are even more evident after 4 ka BP and especially after 2.1 ka BP. Based on soil investigations, elemental fluxes are detected along the slopes with distinct accumulations at the footslope. Evidence for anthropogenic influences and subsequent regressive soil formation phases appear in this pre-alpine landscape about 5 ka BP (Neolithic/Early Bronze Age), which appears to intensify after 2.1 ka BP (Roman period to present). Multi-elemental signatures enabled us to identify the important geochemical processes that have occurred here. Together with radiocarbon and pollen analyses, we placed these processes in a logical temporal context. The use of lacustrine (lake or mire) sediments has great potential to decipher and detail the surrounding landscape history and soil evolution of this region of Switzerland. [ABSTRACT FROM AUTHOR]

Landscapes are subjected to surface denudation during their complex and non-linear evolution. In order to quantify the in situ surface lowering and, thus, denudation or soil erosion rates, new, multi-millennia archives are needed and must be rigorously tested. Large residual rocks, tors, are the basis for the Tor Exhumation Approach. Here we present novel results on meta-sedimentary (schist) rock tors using this approach, which previously has only been applied in granitic terrains. The exhumation patterns of eight schist tors in three landscape locations (valley, ridge, distal) of Otago, New Zealand, were studied using cosmogenic dating. The in situ 10Be ages have high variability along individual vertical tor profiles. Average surface age is 122 ± 12 ka and ranges from 836 ± 89 ka to 19 ± 2 ka. The majority of investigated tors have surfaced during the MIS 5 which was one of the wettest and warmest climate periods. The resulting surface denudation trend of the three locations differs. The valley commenced denudation no earlier than ~200 ka with rates of ~0.22 [m kyr−1] to ~0.02 [m kyr−1]. In contrast, exposure started at the ridge position around 230 ka at ~0.03 [m kyr−1]. An age inversion found in the valley is considered to be the result of mushroom-like exposure by undercutting and repeated rock breakoffs. The distal site tor has been exhumed continuously for ~120 ka at a rate of ~0.2 to ~0.05 [m kyr−1]. We identified a mix of surface emergence patterns of the tors such as continuous-, mushroom-, tafoni- and structural-like. The comparison to modern erosion rates indicates that surface erosion has increased up to a factor of ten during the last few decades. To determine the actual surface uplift, we linked the tor derived surface denudation rates with rock uplift data. The data indicates that the surface uplift rates started to decrease during the Middle Pleistocene (0.04–0.09 [m kyr−1]), remained relatively low during the Late Pleistocene (~0.01 [m kyr−1]) and started to increase again during the Holocene (c. 0.21–0.64 [m kyr−1]). In summary, the emergence pattern of local tors enabled reconstruction of the evolution of Pleistocene-Holocene surfaces in East Otago. [Display omitted] • In situ 10Be ages determined on meta-sedimentary (schist) tors, New Zealand • Tors were primarily exposed during warm and humid MIS 5 (~130–71 ka). • Tor derived surface denudation rates range from ~0.04 to ~0.22 [m kyr−1]. • Surface erosion rates appear to have increased during the last few decades. • Climate and tectonic uplift drive tor exposure in Otago. [ABSTRACT FROM AUTHOR]

• The integrated soil quality index produced more plausible results than the Nemoro index. • Slope and elevation significantly influence soil quality. • Organic matter and grain size play a dominant role on the soil quality. • High erosion rates keep soil quality low to moderate in the Kan catchment. • Soil quality can be evaluated precisely enough by using the minimum dataset. The objective of this study was to better understand the functional links between soil quality, erosion, geomorphology and land-use. This was done for the Kan catchment of the Tehran province, central Iran. Soil quality was assessed by using the integrated quality index (IQI) and the Nemoro quality index (NQI): this enabled the total and minimum datasets (TDS) to be obtained by using the principal component analysis. Soil erosion was calculated using the revised universal soil loss equation (RUSLE) model using the InVEST software. The calculated erosion rates are very high (on average 7 t ha−1 yr−1) in the region due to the variety of topography, steep slopes and lack of suitable vegetation. The variety of topography and steep slopes are a caused by the high uplift rates. Consequently, the modelled actual erosion rates are in the same order of magnitude as measured, long-term denudation rates (10Be). The erosion rates in the rangeland were higher than in agriculture land and built-up areas and exhibit a positive correlation with elevation and slope angle. The integrated soil quality index produced more plausible results than the NQI. According to the IQI, the soils in the study area mostly have a moderate to low quality. The statistical analyses showed that organic matter and sand play a more important role on the soil quality than all the other soil characteristics. Slope and elevation seem to significantly influence the soil quality. We demonstrated that soil quality can be evaluated precisely enough by using the minimum dataset (which reduces costs and time) and that it is dependent only on a few soil parameters. Soil quality and erosion rates vary strongly in areas having a rough and steep topography and the effect of land-use is partially overshadowed. [ABSTRACT FROM AUTHOR]

• No correlation between 239+240Pu inventories and forest landscape attributes exist. • Pu isotopes indicate no erosion for the last decades in the Melzower forest. • Forest soil thickness reveals strong ancient erosional and depositional processes. • 239+240Pu and soil morphology help to separate ancient from recent processes. Forested areas are assumed not to be influenced by erosion processes. However, forest soils of Northern Germany in a hummocky ground moraine landscape can sometimes exhibit a very shallow thickness on crest positions and buried soils on slope positions. The question consequently is: Are these on-going or ancient erosional and depositional processes? Plutonium isotopes act as soil erosion/deposition tracers for recent (last few decades) processes. Here, we quantified the 239+240Pu inventories in a small, forested catchment (ancient forest "Melzower Forst", deciduous trees), which is characterised by a hummocky terrain including a kettle hole. Soil development depths (depth to C horizon) and 239+240Pu inventories along a catena of sixteen different profiles were determined and correlated to relief parameters. Moreover, we compared different modelling approaches to derive erosion rates from Pu data. We find a strong relationship between soil development depths, distance-to-sink and topography along the catena. Fully developed Retisols (thicknesses > 1 m) in the colluvium overlay old land surfaces as documented by fossil Ah horizons. However, we found no relationship of Pu-based erosion rates to any relief parameter. Instead, 239+240Pu inventories showed a very high local, spatial variability (36–70 Bq m−2). Low annual rainfall, spatially distributed interception and stem flow might explain the high variability of the 239+240Pu inventories, giving rise to a patchy input pattern. Different models resulted in quite similar erosion and deposition rates (max: −5 t ha−1 yr−1 to +7.3 t ha−1 yr−1). Although some rates are rather high, the magnitude of soil erosion and deposition - in terms of soil thickness change - is negligible during the last 55 years. The partially high values are an effect of the patchy Pu deposition on the forest floor. This forest has been protected for at least 240 years. Therefore rather natural events and anthropogenic activities during medieval times or even earlier must have caused the observed soil pattern, which documents strong erosion and deposition processes. [ABSTRACT FROM AUTHOR]

The relationship between the spatial variability of soil elements, weathering and erosion rates can be very complex. Topography, abruptly-changing elevation gradients and slopes of varying geological composition exert an important influence on weathering trajectories and erosion. This complex interconnectivity is only rarely addressed in weathering studies. The main objectives of this investigation are, therefore, to relate weathering and erosion to various and geomorphic units in a dry-alpine and threshold landscape having steep slopes (Kan catchment, Tehran Province, Iran). A number of common weathering indices were tested using a genetic algorithm. The best indices are the (K + Na)/Ti ratio, the WIP (weathering index according to Parker), and the PI (product index according to Ruxton). However, the recently suggested 4Si-M+-R2 and M-F-W min systems discriminate weathering trends more accurately. Our results show that these soils have a low to moderate weathering stage. Weathering trajectories point to the active formation of kaolinite and oxyhydroxides. River sediments are slightly more weathered and contain the most-weathered topsoils and suggest erosion in the catchment is predominantly due to topsoil removal. Chemical weathering is influenced by the dominant geomorphic units (unconsolidated deposits of the Quaternary and solid bedrock) and landform features (combination of altitude and slope). Aspect does not appear to have a significant impact on weathering. Denudation (~erosion) rates were determined using meteoric 10Be since the fluvial sediments did not contain enough quartz for in situ 10Be analyses. This procedure has higher uncertainties due to difficulties in estimating the depositional flux of meteoric 10Be. Due to tectonic uplift, the erosion rates are very high. To maintain a soil layer, soil production rates must be also high. Although annual precipitation is relatively low, slope and soil dynamics seem particularly high, which leads to a fast turnover of the soil material and maintains the weathering intensity at a rather low to intermediate level. • The 4Si-M+-R2+ and M-F-W min systems trace chemical weathering of soils and sediments. • High erosion rates in a dry alpine area were coupled to moderate chemical weathering. • Meteoric 10Be is useful in tracking denudation rates, but prone to higher uncertainties. • Denudation in the Kan catchment is predominantly due to soil erosion. • Weathering and erosion rates are affected by geomorphic units, geology and landform. [ABSTRACT FROM AUTHOR]

Granitic landforms such as boulders and tors adorn the upland of several landscapes worldwide. The rate of emergence of these tors from surface could be an indicator of surface lowering over time. Therefore, tors might be a good archive of soil erosion rates over time. We applied in-situ cosmogenic nuclide techniques (10Be) along vertical landforms (tors, boulders and scarps) on the upland of the Sila Massif in southern Italy, to explore their exhumation and formation pattern. The investigation aimed at deciphering surface denudation models covering the last 100 ka. The modelled surface denudation rates are mostly in the range of 0–0.37 mm year-1 and revealed different patterns for individual landforms. The local emerging scarps indicated the highest surface and soil denudation rates of up to 0.40 mm year-1 and demonstrate a rather fast bedrock exposure within the last 8–15 ka. From 75 ka BP to 17 ka BP, the soil erosion rates were low, but increased thereafter strongly. For the last 5000 years, however, the rates continuously have decreased. Three key factors were identified for these developments – climate, vegetation and topography. The climate was principally colder and drier between 75 and 17 ka BP compared to today. We report that during the transition from the Pleistocene to the Holocene a prompt change towards a warmer and humid environment was accompanied by increased denudation rates. With time, the growing density of the vegetation cover (e.g. forest) acted as antagonist to surface denudation.Topography seemed to control the extent of the past increase denudation rates. We found out that slopes experienced higher denudation rates than planar surfaces. Overall, our data suggest that i) tors and boulders are potentially very valuable archive for tracing surface lowering and ii) climate and vegetation were the controlling factors of paleosurface denudation processes. [ABSTRACT FROM AUTHOR]