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Fens are the predominant peatlands in temperate regions and provide key ecosystem services such as water retention and carbon sequestration. Under threat of drainage, discharge of polluted water, and subsequent eutrophication, fen conservation is a priority. A key feature of fens is their high biodiversity, particularly of specialist bryophytes that play a pivotal role in peat formation. Since many mosses are poor competitors, increased growth of vascular plants following eutrophication is often remediated by annual mowing with litter removal. The precise mowing method favoring bryophytes is rarely investigated, yet creation of “recruitment gaps” by mowing of the bryophyte layer has been recommended. We performed a 3‐year field experiment with three annual treatments: (1) mowing of the bryophyte and vascular plant layer to create gaps, (2) only mowing of vascular plants above the bryophyte layer, and (3) not mowing. Our results show that mowing of bryophytes is detrimental for endangered bryophytes, specifically Sphagnum contortum, S. teres, Warnstorfia exannulata, Calliergon giganteum, and Hamatocaulis vernicosus. Only the generalist species S. palustre and Calliergonella cuspidata benefited from bryophyte mowing. We also found that accretion of the bryophyte layer and development of micro‐topography are impeded by bryophyte mowing, potentially hampering future water retention and carbon sequestration. Nevertheless, mowing of vascular plants proved necessary as fen specialists S. teres, S. contortum, S. subsecundum, W. exannulata, and Bryum pseudotriquetrum declined in the unmown treatment. We conclude that, if mowing is necessary to remediate eutrophication, it should be restricted to vascular plants, particularly in fens with endangered bryophytes. [ABSTRACT FROM AUTHOR]

Ion-adsorption rare earth element (REE) deposits are a major source of REEs and are found mainly in China. The formation of such deposits is affected by a combination of endogenic and exogenic factors. This study investigated the effect of micro-topography on the REE distribution in four weathering profiles at different topographic sites on a knoll in Hedi, Zhejiang Province, China. The weathering profile and REE accumulation are both most developed at mid-slope positions of the knoll. The intensity of chemical weathering decreases in the order of mid-slope > base > summit. As weathering progressed, REE enrichment initially increased but later decreased, with a progressive increase in light/heavy REE fractionation. REE fractionation is more pronounced on the north-facing slope than on the south-facing slope. Weathering degrees and clay mineral characteristics are key factors influencing the varying REE distributions on the knoll. Water leaching and the evolution of clay minerals towards higher maturity reduce REE adsorption capacity. Clay minerals also play a significant role in REE fractionation; the abundance of these minerals and the presence of illite enable the retention of more HREEs with minimal desorption. Taking into account water content, it is inferred that hydrological conditions, modulated by the micro-topography, strongly affect the depth and extent of REE accumulation, as well as fractionation. [ABSTRACT FROM AUTHOR]

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Accurately characterizing rainfall runoff processes in plain farmland, especially at the plot scale with significant micro-topographic features, has presented challenges. Integrated surface–subsurface flow models with high-precision surface flow modules are appropriate tools, yet open-source versions are rare. To address this gap, we proposed an open-source integrated surface–subsurface flow model called the FullSWOF-Plain model, in which the one-dimensional subsurface module Hydrus-1D was integrated with a modified two-dimensional surface water flow module (FullSWOF-2D) using the sequential head method. Various experimental scenarios were simulated to validate the model's performance, including two outflow cases (i.e., 1D and 2D) without infiltration, a classical one-dimensional infiltration case, and two typical rainfall events at the experimental field. The results demonstrate the accuracy of this proposed model, with the Nash–Sutcliffe efficiency (NSE) of the simulated discharge exceeding 0.90 in the experimental field case and the root mean squared error (RMSE) values for soil moisture at five depths consistently below 0.03 cm3/cm3. However, we observed a lag in the simulated response time of soil moisture due to the neglect of preferential flow. The micro-topography significantly influenced ponding time and ponding areas. Lower local terrain normally experienced earlier surface ponding. Scattered surface ponding water first occurred in the ditch and followed in the relatively low areas in the main field. The concentration process of surface runoff exhibited hierarchical characteristics, with the drainage ditch contributing the most discharge initially, followed by the connection of scattered puddles in the main field, draining excess surface water to the ditch through rills. This quantitative study sheds light on the impact of micro-topography on surface runoff in plain farmland areas. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural rainfall affects the stability of soil aggregates by the kinetic energy of the rain changing the morphological characteristics of slope micro-topographic factors. Although the relationship between the stability of soil aggregates and micro-topography is not very significant at the slope scale, there are also rules to be found. This study aims to explore the relationship between slope micro-topography and aggregate stability, and to observe the spatial distribution of aggregate stability after water erosion. In this study, a digital elevation model of slope micro-topography was established by using a three-dimensional laser scanner to observe the slope erosion changes after rainfall events and clarify the spatial changes of soil aggregate stability and its relationship with slope micro-topography by combining geostatistics and generalized additive model (GAM). The results showed that the area of serious water erosion in the lower part of the slope accounted for 38.67% of the slope, and the micro-topography index of the slope changed obviously after rainfall, with the slope increasing by 3.1%, the surface roughness increasing by 5.34%, the surface cutting degree increasing by 26.67%, and the plane curvature decreasing by 61.7%. In addition, the GAM model was used to fit the multivariate variables. The results revealed that the slope and surface roughness were the key factors affecting the stability of water-stable aggregate. The slope and surface roughness were negatively correlated with the stability of water-stable aggregates. [ABSTRACT FROM AUTHOR]

Understanding the influence of roughness and terrain slope on stable boundary layer turbulence is challenging. This is investigated using observations collected from October to November of 2018 during the Stable Atmospheric Variability ANd Transport (SAVANT) field campaign conducted in a shallow sloping Midwestern field. We analyze the turbulence velocity scale and its variation with the mean wind speed using observations up to 10–20 m on four meteorological towers located along a shallow gully. The roughness length for momentum over this complex terrain varied with wind direction from 0.0049 m to a maximum of 0.12 m for winds coming through deciduous trees present in the field. The variation of the turbulence velocity with wind speed shows a transition from a weak wind regime to a stronger wind regime, as reported by past studies. This transition is not observed for winds coming from the tree area, where turbulence is enhanced even for weak wind speeds. For weak stratification and stronger winds, the turbulent velocity scale increased with an increase in roughness while the terrain slope is seen to have a weak influence. The sizes of the dominant turbulent eddies seen from the vertical velocity power spectra are observed to be larger for winds coming through the tree area. The turbulence enhancement by the trees is found to be strong within a fetch distance of 7 times the tree height and not observable at 16 times of the tree height. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] The present paper aimed to analyze the spatial distribution characteristics of soil physicochemical properties and soil enzyme activities in different micro-topography and their differences, and to explore the interrelationship between them, which can provide a theoretical basis for the study of alluvial fan development mechanism, ecological restoration and agricultural production in the eastern part of the Helan Mountain. [Method] The physical and chemical properties of soil and soil enzyme activity were analyzed in different micro-topography ( alluvial terrace, high diffuse beach, slotted beach and gully bed) and soil depth ( 0 - 20, 20 - 40 cm) based on field survey sampling and laboratory analysis, and the relationship between soil enzyme activity and soil physical and chemical properties was investigated by using geographic probe combined with exemplary ranking method. The relationship between soil enzyme activity and soil physicochemical properties was investigated using a geodetector combined with the canonical ranking method. [ Result] In different micro-topography, the contents of soil gravel, organic matter, total nitrogen and alkaline nitrogen showed that alluvial terrace > alluvial terrace > trough terrace > furrow bed, and the contents of fast-acting phosphorus and fast-acting potassium showed that alluvial terrace > trough terrace > furrow bed, and the contents of each element decreased with the increase of soil thickness; The differences of soil pH, total phosphorus and total potassium were not significant in different micro-topography; Soil enzyme activities in different micro-topography showed that Alkaline phosphatase and urease activities were the highest in alluvial terraces and the lowest in gully beds, while catalase and peroxidase activities were the highest in gully beds and the lowest in alluvial terraces. The activities of alkaline phosphatase, urease and peroxidase decreased with the increase of soil thickness, and the activities of peroxidase increased with the increase of soil thickness. The results of geodetecting showed that the spatial variation of soil enzyme activities in different micro-topography in the study area was the result of the joint action of various soil physicochemical properties, and different factors had different degrees of influence on soil enzyme activities. Further redundancy analysis showed that total nitrogen, alkaline nitrogen, soil gravel content and fast-acting potassium were the main indicators influencing the variation of soil enzyme activity in the alluvial fan area of the eastern Helan Mountains, with the following order of importance: Total nitrogen > alkaline nitrogen > soil gravel content > fast-acting potassium. [Conclusion] The distribution of soil enzyme activity in the alluvial fan area of the eastern Helan Mountain varies significantly between different micro-topographic soils, and the effect of each soil physical and chemical property on soil enzyme activity varies, revealing the complexity of the relationship between soil physical and chemical properties and soil enzyme activity and the diversity of factors affecting the variation of enzyme activity spatial distribution. [ABSTRACT FROM AUTHOR]

Utilizing the ice thickness data， temperature data， relative humidity data， meteorological reanalysis data and topographic elevation data obtained from the icing monitoring system of ultra-high-voltage transmission lines in China Southern Power Grid， combined with the numerical model of icing， this paper analyze the spatial and temporal distribution characteristics of a large-scale sustained icing on transmission lines in the Yunnan-Guizhou Plateau during January 24 -28， 2018.In addition， the cause of the weather is analyzed.Results show that： （1） Transmission lines in central part of Guizhou Province are the first to monitor the ice-covered， with an overall ice-covered duration length of 60 to 120 hours， and ninety percent of transmission lines have an ice-covered thickness larger than 15 millimeters， with a maximum can reach 50.74 millimeters.Transmission lines in Yunnan Province and northeastern Guangxi Province have an ice-covered duration length of 0 to 10 hours and 40 to 80 hours， respectively， with a maximum ice-covered thickness no more than 25.22 millimeters.（2） The correlation coefficient between the model simulation results and the monitoring data is above 0.9， passing the significance test with ninety-five percent confidence level （when the P value is equal to 0.049）.However， complex terrain has a significant impact on the simulation icing on transmission lines.Best simulation of transmission line ice cover for altitudes of 920 -1060 m， slopes of 7.73°~20.3°， northwest pass and northeast pass.The liquid water content of transmission lines with elevations below 920 m or slopes greater than 20.3° is overestimated.Underestimated wind speeds on transmission lines in southwest and southeast pass.The simulation results for the above two terrain backgrounds are not good.（3） The "high north and low south" potential height field and the "two troughs and one ridge" stable circulation situation in Eurasia will continuous steadily transport the cold air gathered in the East Siberian region to the south of China.In addition， the active southern branch trough and the existence of low-level southwest rapids （wind speed larger than twenty meters per second） make the abundant water vapor in the South China Sea & the Bay of Bengal continuously transported northward， providing stable water vapor conditions for this widespread ice cover event.

Copyright of Plateau Meteorology is the property of Plateau Meteorology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ptilostemon greuteri is one of the most endangered and poorly studied woody vascular plant species of the Mediterranean Basin, endemic to Sicily (Italy). Several peculiar traits confer to P. greuteri a character of uniqueness and an enigmatic attractiveness. In fact, at first glimpse the largest individuals of this species remind the most remarkable and peculiar cases of herbaceous genera (e.g., Echium, Senecio) turned woody on insular or insular-like mountain ecosystems. Following the discovery of a second population of this rare species, a project aiming at the study and conservation of P. greuteri was set up. We present here updated information on the distribution, conservation status, biology and ecological requirements of this species. Field surveys supported by drone imagery were carried out to estimate the current range of the two populations. The data obtained allowed to refine the conservation status assessment of the species and to update the distribution pattern of P. greuteri by means of detailed digital maps of each population. Ongoing field investigations currently provide valuable information about the ecological requirements of the species and point out the impact of wildfires on population size and structure. Our research has also highlighted several knowledge gaps that need to be filled to apply more effective conservation measures. Preliminary results suggest that local topographic and mesoclimatic factors (air humidity and shade) are key variables explaining the persistency and survival of P. greuteri in the area.

For developing performing medical devices, the biomechanical adaptation plays a key role for both, the bulk material (at macro scale) and surfaces (at micro/nano scale). As concerning the interaction of living cells with artificial surfaces, the cellular mechano‐sensitivity has direct effects on tissue structure and functions. In this work, surfaces architectures, obtained by self‐nano‐crystallization, were realized on a gum‐alloy as substrate (titanium‐niobium‐zirconium‐iron‐oxygen), using silicone masks with micrometric patterns/perforations, on which a near‐surface‐severe‐plastic‐deformation process was applied. For finding 3D suitable geometries of the perforations and their distribution on the masks, generative design algorithms were developed using dedicated software tools. The masks were obtained by 3D printing using the fused filament fabrication method. Multidirectional repeated mechanical impacts on the sample surface with high velocity balls at high strain rates were applied. Deeper compressive residual stresses are generated, creating a superficial self‐nano‐crystallized structure on un‐covered areas, due to small volume‐multidirectional local plastic deformation. The applied parameters have a direct effect on local micro‐topography and microstructure evolution. [ABSTRACT FROM AUTHOR]

Plant functional traits can reflect response strategies of plants to environmental changes. In this study, we used a one-way ANOVA and redundancy(RDA)to compare the differences in leaf functional characters of Dicranopteris pedata in three micro-topographies(ridge, slope and valley of the ephemeral gully)and to analyze the response and adaptation strategy of D. pedata to shallow trench micro-topography. The results were as follows:(1)The overall variation degree of leaf functional characters of D. pedata was between 0.05 and 0.47. Both leaf thickness and leaf area were showed as the order of valley > slope > ridge(P<0.05). The leaf N content at the slope was significantly higher than that at the ridge and valley. The leaf P content was significantly lower at the ridge than those at the slope and valley. There was no significant differences in specific leaf area and leaf C content among three micro-topographies.(2)D. pedata at the ridge reduced water loss to protecte itself by reducing leaf area. D. pedata at the slope increased the photosynthetic rate of leaves to promote growth by increasing the N content of leaves. D. pedata at the valley improved light capture ability to promote growth by increasing the leaf area. The above results indicate that due to the differences of soil nutrients, temperature and humidity conditions, D. pedata can achieve better adaption to the environment by adjusting nutrient content and changing leaf morphology. [ABSTRACT FROM AUTHOR]

Copper thin film has been identified as a promising material for multi-level interconnecting materials in IC fabrication due to its unique electrical properties and high electrical conductivity. However, it is very challenging to manufacture a superior planar surface with low dishing and minimal erosion of copper thin film in the chemical mechanical polishing (CMP) process. In this study, the micro-topography model of a soft polishing pad is performed using an X-ray micro-computed tomography scan combined with finite element method simulation to evaluate the contact area between the CMP pad and wafer during the CMP process. Additionally, the material removal rate (MRR) model for the copper wafer is calibrated based on the wear of the material between abrasive particles and the wafer surface. The results of this study not only investigate the effect of CMP pad asperities during the CMP process but also provide a new method for fully calibrating MRR in comparison with CMP experiments for the verification of model parameters. [ABSTRACT FROM AUTHOR]

Abstract The hummock–depression micro‐topography characteristics of the alpine marshy wetland in Sanjiangyuan are indicative of wetland degradation and the process by which healthy wetlands are transformed into flat grasslands. The aim of the present study was to examine changes in plant community structure and soil characteristics in a hummock–depression micro‐topography along a degradation gradient. We observed that: (a) the height and cover of dominant hydrophytes decreased gradually with an increase in degradation severity, leading to replacement by xerophytes; (b) with the transition from healthy to degraded wetlands, hummocks became sparser, shorter, and broader and became merged with nearby depressions; water reserves in the depressions shifted from perennial to seasonal, until they dried out completely; and (c) soil moisture content, porosity, hardness, and organic matter gradually decreased by 30.61%, 19.06%, 37.04%, and 73.27%, respectively, in hummocks and by 33.25%, 8.19%, 47.72%, and 76.79%, respectively, in depressions. Soil bulk density, soil electrical conductivity, and soil dry weight increased by 31%, 83.33%, and 105.44%, respectively, in hummocks, but by only 11.93%, 7.14%, and 97.72%, respectively, in depressions. The results show that hummock soils in healthy wetlands have strong water absorption properties, through which plant roots can penetrate easily. Wetland degradation reduces the water absorption capacity of hummock soil and soil saturation capacity of depressions, thus enhancing soil erosion potential and susceptibility to external factors. Soil moisture is a key environmental factor influencing wetland degradation, and grazing accelerates the process. Based on the changes observed in hummock morphology, vegetation, and soil properties along a degradation gradient, a conceptual model is proposed to illustrate the process of gradual degradation of marshy wetlands from healthy to transitional wetlands and finally to a degenerated state. Thus, our research provides insights into the degradation process of the alpine marshy wetland ecosystem in Sanjiangyuan.

Soil erosion is one of the main environmental threats to sus-tainability and crop productivity in the agricultural sector. In agricultural fields, no-till management is considered a key approach for mitigating soil erosion. The measurement of soil erosion is par-ticularly challenging, especially when surficial morphological changes are relatively small. Conventional experiments are com-monly time-consuming and labour-intensive in terms of both field surveys and laboratory methods. On the other hand, the structure from motion (SfM) photogrammetry technique has enhanced the experimental activities by enabling the temporal evolution of soil erosion to be assessed through detailed micro-topography. This work presents a multitemporal quantification of soil erosion, using SfM through uncrewed aerial vehicles (UAV) survey for under-standing the evolution of no-till (NT) and conventional tillage (CT) in experimental plots. Considering that morphological changes at the plot scale had millimetre orders of magnitude, it was necessary to minimise SfM errors (e.g., co-registration and interpolation) in volumetric estimates to reduce noise as much as possible. Therefore, a methodological workflow was developed to analyse and identify the effectiveness of multi-temporal SfM-derived products, e.g., the conventional difference of digital terrain models (DoDs) and the less used differences of meshes (DoMs), for soil volume computations. We validated the erosion volumetric changes calculated from the SfM outputs with the amount of soil directly collected through conventional runoff and sediment measurements in the field. In this way, we recognised the most suitable estimation method. This study presents a novel approach for using DoMs instead of DoDs to describe the micro-topography changes and sediment dynamics accurately. Another key and innovative aspect of this work often overlooked in soil erosion studies, was identifying the contributing sediment surface by delineating the channels potentially routing runoff directly to water collectors. The sediment paths and connected areas inside the plots were identified using a multi-temporal analysis of the sediment connectivity index for achieving the volumetric estimates, using DoMs (e.g., 2213 cm3 for no-till management system - NT and 38155 cm3 for conventional tillage regime - CT during September 2018-June 2020) that showed mild overestimation respect to field measurements results (e.g., 2359 cm3 for NT and 4525 cm3 for CT in the same period). This difference was attributable to other factors (e.g., the soil compaction processes) or variables rather than to photogrammetric or geometric ones. The developed workflow enabled low cos quantification of soil erosion dynamics for assessing the mitigation effects of no-till management that can also be extended in the future to different scales, based on SfM and UAV technologies. [ABSTRACT FROM AUTHOR]

Purpose: To mechanically characterize and assess the biological properties of Ti6Al4V surfaces obtained by Selective Laser Melting in order to determine whether this process is conceivable for production of implant‐supported prostheses and particularly trans‐gingival components. As‐built and polished surfaces were studied in comparison with components obtained by computer numerical control machining technology in order to consider whether the properties are in the same range as the conventional method currently used. Materials and Methods: Cylindrical specimens of Ti6Al4V (n = 6) were built with Selective Laser Melting for the characterization of mechanical properties according to ISO 22674 and discs (n = 12) were fabricated in the same conditions for cytotoxicity evaluation. Discs (n = 12) of Ti6Al4V were also obtained by computer numerical control machining as control. Half of the number of discs (n = 6) from each process were polished, to simulate the laboratory protocol for polishing of transmucosal components and half of the discs remained unaltered (as‐built). Surface roughness measurements of disc specimens (as‐built and polished) were compared with computer numerical control milling specimens (as‐built and polished). Proliferation of human gingival fibroblasts on Ti6Al4V surfaces was also assessed for each condition. Viability and cell morphology were then evaluated qualitatively. Ra and Sa data were compared using Student's t‐test (α = 0.05) and metabolic activity data were compared using Kruskal‐Wallis statistical test (α = 0.05). Results: Selective Laser Melting specimens showed elongation at break greater than 2% and 0.2% yield strength better than 500MPa which complied with ISO 22674 standards. Although Selective Laser Melting samples displayed significantly increased roughness on as‐built surfaces compared to computer numerically controlled milling samples (p < 0.05), no statistically significant difference was observed after mechanical polishing (p = 0.279). Regarding metabolic activity, no statistical difference was observed between groups at day 3 (p > 0.05) and fibroblasts showed a viability higher than 97% on all discs. Cell shapes on polished samples suggested moderate adhesion compared to unpolished samples. Conclusion: With the manufacturing parameters selected in this study, Selective Laser Melting of Ti6Al4V appeared to be compatible with a prosthetic application type 4 according to ISO 22674. Surfaces obtained, followed by recommended postprocessing provided components with equivalent biological properties compared to computer numerical control machining technology. [ABSTRACT FROM AUTHOR]

Soil erosion is one of the main environmental threats to sustainability and crop productivity in the agricultural sector. In agricultural fields, no-till management is considered a key approach for mitigating soil erosion. The measurement of soil erosion is particularly challenging, especially when surficial morphological changes are relatively small. Conventional experiments are commonly time-consuming and labour-intensive in terms of both field surveys and laboratory methods. On the other hand, the structure from motion (SfM) photogrammetry technique has enhanced the experimental activities by enabling the temporal evolution of soil erosion to be assessed through detailed micro-topography. This work presents a multitemporal quantification of soil erosion, using SfM through uncrewed aerial vehicles (UAV) survey for understanding the evolution of no-till (NT) and conventional tillage (CT) in experimental plots. Considering that morphological changes at the plot scale had millimetre orders of magnitude, it was necessary to minimise SfM errors (e.g., co-registration and interpolation) in volumetric estimates to reduce noise as much as possible. Therefore, a methodological workflow was developed to analyse and identify the effectiveness of multi-temporal SfMderived products, e.g., the conventional difference of digital terrain models (DoDs) and the less used differences of meshes (DoMs), for soil volume computations. We validated the erosion volumetric changes calculated from the SfM outputs with the amount of soil directly collected through conventional runoff and sediment measurements in the field. In this way, we recognised the most suitable estimation method. This study presents a novel approach for using DoMs instead of DoDs to describe the microtopography changes and sediment dynamics accurately. Another key and innovative aspect of this work often overlooked in soil erosion studies, was identifying the contributing sediment surface by delineating the channels potentially routing runoff directly to water collectors. The sediment paths and connected areas inside the plots were identified using a multi-temporal analysis of the sediment connectivity index for achieving the volumetric estimates, using DoMs (e.g., 2213 cm3 for no-till management system - NT and 38155 cm3 for conventional tillage regime - CT during September 2018-June 2020) that showed mild overestimation respect to field measurements results (e.g., 2359 cm3 for NT and 4525 cm3 for CT in the same period). This difference was attributable to other factors (e.g., the soil compaction processes) or variables rather than to photogrammetric or geometric ones. The developed workflow enabled low cos quantification of soil erosion dynamics for assessing the mitigation effects of no-till management that can also be extended in the future to different scales, based on SfM and UAV technologies.

Soil moisture is a limiting factor for vegetation restoration on the Loess Plateau, China. Micro-topography may cause heterogeneities in the distribution of soil moisture, but little is known about its effect on deep soil moisture. Our study aims to explore the distribution and impact of soil moisture within the upper 10 m of soil for different microtopographies. Taking undisturbed slope as the control, five micro-topographies were selected. Soil moisture over a depth of 0–10 m from 2017 to 2019 was investigated, and soil particle size and soil organic matter were measured. Variance analysis and multiple comparisons were used to analyze the difference in soil moisture for different microtopographies and multiple-linear regression was used to analyze the influence of micro-topography on soil moisture. There are significant differences in soil moisture within the different layers underlying the examined micro-topographies, while the inter-annual variation in soil water storage for the selected microtopographies increase with increased rainfall. The depth of influence of micro-topographic vegetation on soil moisture exceeded 1000 cm for a gully (GU), 740 cm for a sink hole (SH), 480 cm for a scarp (SC), 360 cm for an ephemeral gully (EG) and 220 cm for a platform (PL). Micro-topography will cause the heterogeneous distribution of soil moisture in the shallower layers, which changes the vegetation distribution differences between micro-topographies. This may be the survival strategy of herbaceous vegetation in response to climate change in the Loess Plateau. For future vegetation restoration efforts, we need to pay attention to the influence of microtopography on soil moisture. [ABSTRACT FROM AUTHOR]

Wetland vegetation dynamics are vital but difficult to understand due to complex impact factors and their spatial heterogeneities. Poyang Lake, the largest freshwater lake in China, is well-known for its ecological importance as a floodplain wetland. However, heterogeneity in vegetation extent and its response to water regimes across different geomorphic units of Poyang Lake remain unclear to date. To address this gap, Landsat images acquired during dry seasons from 1987 to 2018 were selected to explore vegetation extent and its response to water level fluctuations across multiple elevation bands and four wetland types, namely Riparian Wetland (RW), Delta Wetland (DW), Dish-shaped Wetland (DSW), and Fan-shaped wetland (FSW). Results show that vegetation extent in lower elevation bands of the four wetland types increased remarkably with an average increase rate of 0.53 km2/year between 2003 and 2018 compared to −0.17 km2/year−1 during 1987 to 2002. Hydrological variables indicating high-flow events negatively affected vegetation extent in DSW while variables indicating low-flow events appear to be positive for vegetation extent in RW, DW, and FSW. Over-long floods as happened in 2016 has caused fatal damage to vegetation extent in DSW. In addition, extreme droughts in recent years caused by the Three Gorges Dam promoted significant (p

The geomorphological characteristics is the most directive reflection of soil erosion results. The mechanism of erosion processes and the influence of the micro-topographic characteristic value of erosion can be revealed by analyzing the fluctuation characteristics of micro-topography on slope. In this paper, the typical karst area of Huaying City is taken as the research area. The three slope gradients of <25°, 25-30° and >30°, five terrain factor eigenvalues, including average slope, slope variability, surface roughness, terrain relief and variation coefficient of elevation, are selected to compare the statistical distribution, entropy weight index and terrain interpretation rate, and to analyze the differences in the description of micro-topographic characteristics of soil erosion with different gradients and scales. The results show that (1) the difference of micro-topography feature values of steep slope (>30°) is significantly greater than that of gentle slope (<25°), and the steeper the slope is, the greater the coefficient values of terrain variation is, so the characteristic values of terrain factors with strong variability should be used to describe, such as the variation coefficient of elevation, terrain relief and surface roughness. (2) With the increase of micro-topographic scale, terrain relief and variation coefficient of elevation are positively correlated with scale change, while average slope, slope variation rate and surface roughness are negatively correlated with scale change. The characteristics of terrain relief and variation coefficient of elevation coefficient are relatively sensitive to scales factors, which recommended in the study of erosion mechanism at the microscale. (3) The four factors of surface roughness, variation coefficient of elevation, terrain relief and average slope are better used to present the slope micro-topographic characteristics comprehensively. The comprehensive terrain interpretation rate is the highest (more than 90%) at the scale of 0.5-1 m, which can well reflect the characteristics information of the micro-topography feature. [ABSTRACT FROM AUTHOR]

The hummock–depression micro‐topography characteristics of the alpine marshy wetland in Sanjiangyuan are indicative of wetland degradation and the process by which healthy wetlands are transformed into flat grasslands. The aim of the present study was to examine changes in plant community structure and soil characteristics in a hummock–depression micro‐topography along a degradation gradient. We observed that: (a) the height and cover of dominant hydrophytes decreased gradually with an increase in degradation severity, leading to replacement by xerophytes; (b) with the transition from healthy to degraded wetlands, hummocks became sparser, shorter, and broader and became merged with nearby depressions; water reserves in the depressions shifted from perennial to seasonal, until they dried out completely; and (c) soil moisture content, porosity, hardness, and organic matter gradually decreased by 30.61%, 19.06%, 37.04%, and 73.27%, respectively, in hummocks and by 33.25%, 8.19%, 47.72%, and 76.79%, respectively, in depressions. Soil bulk density, soil electrical conductivity, and soil dry weight increased by 31%, 83.33%, and 105.44%, respectively, in hummocks, but by only 11.93%, 7.14%, and 97.72%, respectively, in depressions. The results show that hummock soils in healthy wetlands have strong water absorption properties, through which plant roots can penetrate easily. Wetland degradation reduces the water absorption capacity of hummock soil and soil saturation capacity of depressions, thus enhancing soil erosion potential and susceptibility to external factors. Soil moisture is a key environmental factor influencing wetland degradation, and grazing accelerates the process. Based on the changes observed in hummock morphology, vegetation, and soil properties along a degradation gradient, a conceptual model is proposed to illustrate the process of gradual degradation of marshy wetlands from healthy to transitional wetlands and finally to a degenerated state. Thus, our research provides insights into the degradation process of the alpine marshy wetland ecosystem in Sanjiangyuan. [ABSTRACT FROM AUTHOR]

Near-surface vegetation and micro-topography have a great impact on the surface runoff process in the mountainous areas of southwestern China. It is, therefore, necessary to clarify the combined influence on the soil and water loss of steep slopes. In this study, 10 natural runoff plots were set to reveal the effects of cypress spatial pattern and micro-topography on the surface runoff. Pearson correlation coefficient method was applied to determine the correlation between cypress spatial pattern, micro-topography, and characteristic parameters of surface runoff. A response surface method (RSM) was also utilized to analyze the measured cypress spatial pattern and micro-topography in the process of precipitation and surface runoff. The results showed that: 1) The peak flow coefficient in all runoff plots behaved short-duration rainstorm (the rainfall lasted no more than 3 h, and the maximum 1 h rainfall intensity exceeded 30 mm/h) > long-duration rainstorm (the rainfall lasted more than 3 h, and the average rainfall intensity exceeded 2.5 mm/h) > long-duration heavy rainfall (the rainfall lasted more than 3 h, and the average rainfall intensity was between 1.5-2.5 mm/h), indicating that the blocking effect of different underlays on surface runoff decreased, with the increase of rainfall intensity and concentration of precipitation. 2) Five factors were significantly correlated with the peak flow (P<0.05) in the long-duration heavy rainfall or rainstorm, including topographic relief, surface roughness, runoff path density, contagion index of cypress, and stand density of cypress. Nevertheless, there was no significant correlation with the peak flow under the condition of short-duration rainstorm. 3) In long-duration heavy rainfall or rainstorm, the response of peak flow to the composite index were that: a) There was no significant change in the peak flow, when the composite index for cypress spatial pattern (V) was below 20.5, while the composite index of micro-topography (U) was below 10.5 (Low surface roughness, high runoff path density, and low stand density of cypress). b) The peak flow was relatively promoted, as the composite index for cypress spatial pattern increased within a certain range, when U > 9.0 (High surface roughness, low runoff path density, low stand density of cypress, and uniform structure among cypress). c) The peak flow was reduced significantly with the increase of V value, when U < 7.5 and V > 18 (Low runoff path density, while high stand density of cypress). As such, when the V value was adjusted to 41 under the condition of long-duration heavy rainfall (rainstorm), an optimal combination was achieved, where the peak flow was reduced from 39.6 L/10 min (14.2 L/10 min) to 6.3 L/10 min (4.2 L/10 min), while the reduction rate reached 84% (70%). d) Once the V value exceeded the critical one (the specific critical value increased with the increase of U value), the dominant influencing factor of peak flow shifted gradually from cypress spatial pattern to micro-topography. This finding can provide promising theoretical support to accurately adjust the vegetation patterns for the prevention and control of soil erosion in the mountainous areas of southwest China. [ABSTRACT FROM AUTHOR]

The Tibetan Plateau, a vulnerable eco‐region undergoing global change, is hard to revegetate where land has become desertified due to the harsh habitat conditions. Sophora moorcroftiana shrubs, which are widely distributed in the middle reaches of the Yarlung Zangbo River basin of Tibet, China, have been naturally restored on desertified land during the last few decades. However, the influences of micro‐topography on the distribution and structure of the S. moorcroftiana population have been rarely reported. Here, we first describe the spatial variation of S. moorcroftiana population on a restored alluvial fan, and then explore the effects of micro‐topography on the restored S. moorcroftiana population, through a series of field surveys combined with the data collected by terrestrial laser scanning. The results indicate that the dominant age structure was adult shrubs (30–60 cm). Although the topographic effect had no significant impacts on soil organic matter and some other structural traits, which remained stable on the restored alluvial fan, it changed population density, plant growth, and distribution. The habitat conditions on the southwest aspect wapproximately 20°–25° slope with altitudes ranging between 3,593–3,643 m, conditions that mostly favouring the distribution of the shrub population. The micro‐topography played an important role in species distribution and growth of the S. moorcroftiana population. Our findings could help to understand the effect of micro‐topography on plant population structure and distribution for ecological restoration of desertified land in the Southern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Topographic heterogeneity provides a potential opportunity for seedling recruitment in the disturbance-dynamic ecosystem. Micro-topography manipulation is the typical way to imitate or recover the natural topographic heterogeneity for the degraded salt marsh restoration. However, it is still not clear how different micro-topographic structures work along the lateral gradient of a tidal creek. In this study, we performed three micro-topographic treatments, i.e., hollow topography, fine and coarse biotic grille structures, to restore the degraded Suaeda salsa wetlands. The results showed that the effectiveness of micro-topography restorations varied with structures and elevation levels. The hollow topography performed well in high marshes by relieving salinity stress and enhancing seeds retention. Moreover, in middle and low marshes, fine biotic grille structure improved the seeds retention and soil conditions better, including soil salinity and moisture, which were critical physico-chemical factors for Suaeda salsa biomass restoration according to redundancy analysis. In contrast, coarse biotic grille structure showed little significance on Suaeda salsa restoration. The findings of this work emphasized that seeds retention and post local soil conditions were significant aspects for salt marsh restoration. Meanwhile, it provided an alternative design for micro-topographic structures by native biotic materials in the complex and dynamic salt marshes. [ABSTRACT FROM AUTHOR]

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Soil water is an important factor restricting afforestation on the semi-arid Loess Plateau. The micro-topography of the loess slope has changed the distribution pattern of soil water on the slope. To improve water utilization efficiency and optimize afforestation configuration patterns, the relationship between soil water and precipitation at micro-topographic scale must be studied. We used time series analysis to study the temporal variation of soil water and its response to precipitation in four kinds of micro-topographies and undisturbed slope on loess slopes. Micro-topographies significantly influenced soil water distribution and dynamics on the slopes. Soil water stored in the platform, sinkhole, and ephemeral gully influenced subsequent soil water for 4 weeks, whereas soil water stored in the scarp and undisturbed slope could influence soil water for 2 weeks. It took 12 weeks, 10 weeks, 18 weeks, 6 weeks, and 12 weeks for precipitation to reach the deeper soil layer in the platform, sinkhole, scarp, ephemeral gully, and undisturbed slope, respectively. These soil water characteristics in different micro-topographies are vital factors that should be taken into consideration when undertaking afforestation on the Loess Plateau. [ABSTRACT FROM AUTHOR]

Background and Aims The growth rate of pioneer species is known to be a critical component determining recruitment success of marsh seedlings on tidal flats. By accelerating growth, recruits can reach a larger size at an earlier date, which reduces the length of the disturbance-free window required for successful establishment. Therefore, the pursuit of natural mechanisms that accelerate growth rates at a local scale may lead to a better understanding of the circumstances under which new establishment occurs, and may suggest new insights with which to perform restoration. This study explores how and why changes in local sediment elevation modify the growth rate of recruiting salt marsh pioneers. Methods A mesocosm experiment was designed in which the annual salt marsh pioneer Salicornia procumbens was grown over a series of raised, flat and lowered sediment surfaces, under a variety of tidal inundation regimes and in vertically draining or un-draining sediment. Additional physical tests quantified the effects of these treatments on sediment water-logging and oxygen dynamics, including the use of a planar optode experiment. Key Results In this study, the elevation of sediment micro-topography by 2 cm was the overwhelming driver of plant growth rates. Seedlings grew on average 25 % faster on raised surfaces, which represented a significant increase when compared to other groups. Changes in growth aligned well with the amplifying effect of raised sediment beds on a tidally episodic oxygenation process wherein sediment pore spaces were refreshed by oxygen-rich water at the onset of high tide. Conclusions Overall, the present study suggests this tidally driven oxygen pump as an explanation for commonly observed natural patterns in salt marsh recruitment near drainage channels and atop raised sediment mounds and reveals a promising way forward to promote the establishment of pioneers in the field. [ABSTRACT FROM AUTHOR]

Background Over 25% of the UK land area is covered by uplands, the bulk of which are comprised of blanket bog. This not only contains most of the UK’s terrestrial carbon stocks, but also represents 15% of this globally rare habitat. About 30% of UK blanket bog is managed for red grouse by encouraging ling heather (Calluna vulgaris) with rotational burning, which has been linked to habitat degradation, with reduced carbon storage and negative impacts on water storage and quality. Alternative cutting is currently being pursued as a potential restoration management. However, the often used heavy cutting machinery could cause considerable compaction and damage to the peat surface. Two particular issues are (i) a potential increase in bulk density reducing water storage capacity (i.e., less pore volume and peat depth), and (ii) a possible reduction of the micro-topography due to cutting off the tops of hummocks (i.e., protruding clumps or tussocks of sedges). Methods We set up a fully replicated field experiment assessing cutting versus burn management impacts on peat physical and surface properties. Both managements reflected commonly used grouse moor management practice with cutting using heavy tractors fitted with load distributing double wheel and tracks (lowering ground pressure), whilst burning was done manually (setting heather areas alight with flame torches). We assessed management impacts on peat depth, bulk density and peat surface micro-topography which either included pre-management measurements or plot-level data for uncut plots. Total peat depth and bulk density in four 5 cm sections within the top 50 cm was assessed. Micro-topography was determined as the standard deviation of the height offsets measured over several plot transects in relation to the plot peat surface level at the start and end points of each transect. Results Despite an anticipated compaction from the heavy machinery used for cutting, the peat showed resilience and there was no lasting plot-level impact on either peat depth or bulk density. Notably, bulk density showed differences prior to, and thus unrelated to, management, and an overall increasing bulk density, even in uncut plots. However, cutting did reduce the plot micro-topography by about 2 cm, mostly due to removing the tops of hummocks, whereas burnt plots did not differ from uncut plots. Discussion Cutting is suggested as a suitable alternative to burning on grouse moors, although compaction issues might be site specific, depending on the nature of the peat, the machinery used and impacts at resting and turning points (which were not assessed). However, any observed bulk density differences could reflect natural changes in relation to changes in peat moisture, requiring adequate experimental comparisons. Moreover, where micro-topography is a priority, cutting equipment might need to consider the specific ground conditions, which could involve adjusting cutting height and the type of cutting machinery used.

• Revegetation effectiveness has been improved greatly on sandy land in 2008–2017. • Micro-topography affects habitat conditions of ecological restoration on sandy land. • Habitat conditions on the southeastern and eastern aspects favor revegetation. • LiDAR can be used to accurately measure revegetation structure on sandy land. The Qinghai-Tibetan Plateau (QTP) is one of the most difficult eco-regions for revegetation on degraded grassland because of its harsh environment. Micro-topography could affect habitat conditions important to ecological restoration on sandy land; however, the interaction between revegetation and micro-topography has been rarely reported on sand dunes of the QTP. Here, we quantified vegetation (including coverage, leaf area index (LAI), height, and crown diameter) and micro-topographic parameters (including elevation, slope, and aspect) to assess the effects of topography on revegetation using field observation data during 2008–2017 and terrestrial laser scanning (TLS) in 2017. The results showed that: 1) the tested plant species for revegetation has changed significantly from 2008 to 2017, and the current dominant plant species were mainly introduced from north China, including Hedysarum scoparium, H. fruticosum, and Artemisia sphaerocephala. 2) The effectiveness of revegetation has been improved remarkably over the past ten years. The vegetation coverage varies from 68.4% to 80.5% at four big quadrats of 20 m × 20 m, while the LAI value varies from 2.30 to 3.27, the shrub height ranges from 1.12 m to 7.57 m, and the crown diameter ranges from 0.24 m to 6.96 m. 3) A total of 153 shrubs were extracted in these four quadrats using TLS; and 56.9%, 21.6% and 10.5% of them are distributed on the southeastern, southern, and eastern aspects, respectively. The height and crown diameter of individual shrubs are significantly correlated with the local slope (p < 0.05) of which could affect the distribution of artificial seeding. These results suggest that aspect and slope are two key limiting factors for revegetation, and the habitat conditions on the southeastern and eastern aspects favor revegetation on valley-slope sand dunes. These findings provide a useful guidance in developing an integrated ecological restoration plan for sand dunes and selecting the best practice management of ecosystem services on degraded grassland on the QTP. [ABSTRACT FROM AUTHOR]

The interactions between soil organic matter (SOM) and micro-topography and vegetation drive the ecology of wetland ecosystems. We investigated the distribution pattern of SOM and its relationships with elevation, slope, aspect, topographic wetness index (TWI), and normalized difference vegetation index (NDVI) in Poyang Lake, the largest freshwater lake of China. The local parameters were obtained by applying a geographically weighted regression model. Local parameter differences were analyzed between two dominant wetland types (dish-shaped pit wetland and delta wetland) and among nine land-cover types (deep water, shallow water, very shallow water, mudflat, meadow, sparse grassland, Carex-Phalaris community, Phragmites-Triarrhena community, and Artemisia-Cynodon community). The SOM response to elevation was most sensitive in the dish-shaped pit wetland and mudflat, whereas the effects of slope on SOM were more significant in the delta wetland and vegetated land-cover types. Relatively weaker correlations were observed between SOM and aspect in all study zones. Positive correlations were found between SOM and TWI, which was strongest in dish-shaped pit wetland and deep water. NDVI was positively related to SOM in most areas, but the relationships were not significant in the southern area and in the mudflat. This study helps to better understand the spatial heterogeneity of Poyang Lake. [ABSTRACT FROM AUTHOR]

• Secondary dispersal is an important process in seagrass meadows. • Microtopography could affect secondary seed dispersal distances. • A theory relating secondary dispersal with the microtopography is formulated. • The formulation is validated with computational fluid dynamics for two seagrasses. • These results can inform seed-based restoration to assess secondary dispersal. Motivated by observational and experimental evidence, a theoretical model is proposed to relate the secondary dispersal of seagrass seeds with the complexity of microtopography in natural environments. Complexity is encoded in terms of the Hurst exponent of a fractal description of the microtopographical geometry. The percentage of a seafloor transect where secondary dispersal of seagrass seeds occurs, is quantified in terms of the mainstream velocity, bottom complexity and properties of the seeds. Theoretical expressions are validated considering the cases of Zostera marina and Posidonia oceanica seeds and using computational fluid dynamics (CFD). A total of 200 CFD simulations with different bottom complexities and flow conditions, were done for each seagrass genus to validate the theoretical model. Numerical results agree with theoretical predictions. This finding provides a management tool to assess the degree of seed retention in seed-based restoration areas. [ABSTRACT FROM AUTHOR]

This systematic review examines effects of surface texture on marine biofouling and characterizes key research methodologies. Seventy-five published articles met selection criteria for qualitative analysis; experimental data from 36 underwent quantitative meta-analysis. Most studies investigated fouling mechanisms and antifouling performance only in laboratory assays with one to several test species. Textures were almost exclusively a single layer of regularly arranged geometric features rather than complex hierarchical or irregular designs. Textures in general had no effect or an inconclusive effect on fouling in 46% of cases. However, effective textures more often decreased (35%) rather than increased (19%) fouling. Complex designs were more effective against fouling (51%) than were regular geometric features (32%). Ratios of feature height, width, or pitch to organism body length were significant influences. The authors recommend further research on promising complex and hierarchical texture designs with more test species, as well as field studies to ground-truth laboratory results. [ABSTRACT FROM AUTHOR]

Background. Over 25% of the UK land area is covered by uplands, the bulk of which are comprised of blanket bog. This not only contains most of the UK’s terrestrial carbon stocks, but also represents 15% of this globally rare habitat. About 30% of UK blanket bog is managed for red grouse by encouraging ling heather (Calluna vulgaris) with rotational burning, which has been linked to habitat degradation, with reduced carbon storage and negative impacts on water storage and quality. Alternative cutting is currently being pursued as a potential restoration management. However, the often used heavy cutting machinery could cause considerable compaction and damage to the peat surface. Two particular issues are (i) a potential increase in bulk density reducing water storage capacity (i.e., less pore volume and peat depth), and (ii) a possible reduction of the micro-topography due to cutting off the tops of hummocks (i.e., protruding clumps or tussocks of sedges). Methods. We set up a fully replicated field experiment assessing cutting versus burn management impacts on peat physical and surface properties. Both managements reflected commonly used grouse moor management practice with cutting using heavy tractors fitted with load distributing double wheel and tracks (lowering ground pressure), whilst burning was done manually (setting heather areas alight with flame torches). We assessed management impacts on peat depth, bulk density and peat surface micro-topography which either included pre-management measurements or plot-level data for uncut plots. Total peat depth and bulk density in four 5 cm sections within the top 50 cm was assessed. Micro-topography was determined as the standard deviation of the height offsets measured over several plot transects in relation to the plot peat surface level at the start and end points of each transect. Results. Despite an anticipated compaction from the heavy machinery used for cutting, the peat showed resilience and there was no lasting plot-level impact on either peat depth or bulk density. Notably, bulk density showed differences prior to, and thus unrelated to, management, and an overall increasing bulk density, even in uncut plots. However, cutting did reduce the plot micro-topography by about 2 cm, mostly due to removing the tops of hummocks, whereas burnt plots did not differ from uncut plots. Discussion. Cutting is suggested as a suitable alternative to burning on grouse moors, although compaction issues might be site specific, depending on the nature of the peat, the machinery used and impacts at resting and turning points (which were not assessed). However, any observed bulk density differences could reflect natural changes in relation to changes in peat moisture, requiring adequate experimental comparisons. Moreover, where micro-topography is a priority, cutting equipment might need to consider the specific ground conditions, which could involve adjusting cutting height and the type of cutting machinery used. [ABSTRACT FROM AUTHOR]

Influence of molding pressure on Ca(OH)2 carbonation reaction was analyzed by temperature and humidity monitoring, cube compressive strength testing, XRD and SEM test. The conclusions are as follows: calcium hydroxide test block formed under 8 MPa exhibited the most violent carbonation reaction, which is reflected in the high temperature and humidity in the carbonation kettle during the carbonation reaction process. When the molding pressure increases from 10 MPa to 14 MPa, the cube compressive strength and weight gain rate both decreased obviously. For 8 MPa molding pressure, the strongest diffraction peak of calcite exhibited sharper front and smaller half height and width, and the calcite generated by Ca(OH)2 reacting with CO2 presents ellipsoidal shape. [ABSTRACT FROM AUTHOR]

The surface scars of the First World War (WWI; 1914–1918) are rapidly disappearing due to modern and fast changing landscapes. Therefore, there is a need to monitor landscape relicts that mark our past. This study examines depressions caused by shelling. These shell holes are still present today and are one of the last remains of the military impact during the 4 years long stalemate on the Western Front. Shell hole landscapes are until now overlooked in landscape research and little attention is given to the causes behind the absence or presence of these shell holes in the present-day micro-topography. This paper aims to identify these causes by using digital interdisciplinary techniques on a landscape scale: Light detection and ranging (LiDAR) giving insights into the presence of the shell holes today, landscape maps indicating the evolution of land use/land cover in the past century and a shell hole density map representing the situation of 1918. Results revealed that the WWI shell hole landscape is still abundantly present today, and where it has disappeared, a direct link was found to land use/land cover transformations and the intensity level of cultivated fields from past to present. To work towards a sustainable management of WWI heritage, these findings are indispensable. [ABSTRACT FROM AUTHOR]

This paper focused on the illumination model of machined surface based on micro-image. According to micro-image forming condition, the theory that the image brightness is related to the microfacet topography and surface reflection characteristics is presented. The distribution rule of micro-topography and reflection characteristics of sample surface is analyzed according to the measured data. An illumination mode of machined surface is established based on the analysis result, and the model parameters are obtained by using the simulated annealing algorithm. Verification results show that this proposed model can improve the simulation accuracy significantly and describe the lighting effect of machined surface. The research will provide a new idea and method for the 3D reconstruction. [ABSTRACT FROM AUTHOR]

Abstract It is rather difficult to achieve uniform surface texture and high convergence rates of surface roughness (CRSR) at the same time in the conventional optical polishing process. The dual-axis wheel polishing (DAWP) technology, which uses a semi-rigid wheel with combined dual-axis rotational movements, shows a strong capability directly changing the rough ground surface status down to mirror status with nanometer level surface roughness, and achieving a uniform and smooth surface texture. In order to provide a better scientific understanding of the surface texture generation in DAWP process, in this paper, two comprehensive mathematical models are proposed. The first model is to predict the generation of micro-topography and roughness within single-axis TIF (tool influence function) area, based on the abrasive wear theory, abrasives distribution investigation and accumulative removal theory. On the basis of this model, another surface micro-topography generation model is also built to predict the micro-topography and roughness generated on workpiece surface in actual DAWP process (both for single and dual-axis modes). A series of fixed spot polishing tests and uniform polishing tests on BK7 glass were carried out to analyze the influence of polishing parameters and motion modes on the generated surface texture and roughness. The measurement results show that the surface micro-topography and roughness within TIF area and on polished surface can be well predicted by the two models. After actual polishing process, the dual-axis mode tends to produce much lower surface roughness with uniform texture. The single-axis mode tends to generate directional surface textures with relatively higher surface roughness. Under the dual-axis mode, the variation of co-rotating speed has less influence on the polishing quality, very high CRSR and uniform texture can be achieved under different co-rotating speeds. Highlights • The surface topography within TIF has a direct effect on the generated surface topography of the polished surface. • A comprehensive model is proposed to predict the generation of topography and roughness within single-axis TIF. • A surface micro-topography generation model of DAWP process is proposed. • Better surface quality with uniform texture and nanometer level roughness is achieved by introducing the dual-axis motion. • The variation of rotational speed of the co-rotating motion has less influence on the surface quality. [ABSTRACT FROM AUTHOR]

The extensive artificially accelerated erosion of spoil heaps on newly engineered landforms is a key ecological management point requiring better understanding. Soil surface roughness is a crucial factor influencing erosion processes; however, study on spoil heap erosion with a view of surface roughness is lacking. This study investigated the erosion processes and the spatiotemporal variation of surface roughness on spoil heaps, and then, analyzed how the roughness affected the hydrological and sediment yield characteristics. Sequences of four artificial rainstorms with constant rainfall intensity (90 mm/h) were applied to cone-shaped spoil heaps (ground radius 3.5 m, height 2.3 m) of a loess soil containing 30 mass percent rock fragments. The surface elevation was sampled by a laser scanner. For the surface roughness indicators, the root mean square height (rmsh) and the correlation length (cl) increased sharply during the first rainfall event, and in the last three rainfall events, rmsh increased slightly and cl showed a relative decrease. The initial rmsh/cl of the whole slope surface ranged from 0.063 to 0.135, and increased with the rainfall sequence, thus, indicating that the spoil heap surface became rougher. Increasing soil roughness in the rainfall sequence delayed the initial runoff time and increased the runoff yield. The average runoff coefficient of the spoil heaps was 0.658. The average erosion rate of each rainfall event can be simulated by a regression equation of the corresponding average runoff rate and median cl (R-square of 0.816). Soil slumping with an average volume of 0.014 m3 occurred in the first two rainfall events, thus, significantly changing the roughness and peak instant erosion rate. Together, the results revealed the effects of surface roughness on the erosion of spoil heaps and would provide a useful reference for soil loss prediction and control.

Phytogenic hillocks are a type of wind-deposited biological micro-topography exhibiting a bulging shape under plant clusters in arid regions. In this study, we quantitatively measured the phenotypic characteristics of phytogenic hillocks, the soil particle size distribution in phytogenic hillocks and bare surfaces, and the sediment particle size distribution in hillocks of three heights under different grazing treatments. The results showed that the proportion of dense cluster phytogenic hillocks in the no grazing treatment was higher than in the moderate grazing treatment, and the proportion of scattered cluster phytogenic hillocks under moderate grazing was higher than under no grazing. The total area of dense cluster phytogenic hillocks under no grazing was higher than under heavy grazing and under moderate grazing. For the scattered cluster phytogenic hillocks, the total area was greatest under moderate grazing, followed by heavy grazing and, finally, no grazing. For single hillocks, grazing had a significant impact on the width of dense cluster phytogenic hillocks, while the heavy grazing treatment had a significant impact on the height of scattered cluster phytogenic hillocks. The results for windblown sediment showed that the only significant difference among grazing treatments occurred at a height of 2-8 cm. Grazing changed the relationships among the phenotypic characteristics of phytogenic hillocks, the soil particle size of phytogenic hillocks, and the particle size of wind-deposited sediments. Our results suggested that grazing increased the proportion of scattered cluster phytogenic hillocks and caused the relationship between somewhat bare land and phytogenic hillocks to change from symbiosis to competition. [ABSTRACT FROM AUTHOR]

Large gullies occur globally and can be classified into four main micro-topographic types: ridges, plane surfaces, pipes and cliffs. Afforestation is an effective method of controlling land degradation worldwide. However, the combined effects of afforestation and micro-topography on the variability of soil moisture remain poorly understood. The primary objectives of this study were to determine whether afforestation affects the spatial pattern of the root-zone (0-100 cm) soil moisture and whether soil moisture dynamics differ among the micro-topographic types in gully areas of the Chinese Loess Plateau. The results showed that in the woodland regions, the spatial mean moisture values decreased by an average of 6.2% and the spatial variability increased, as indicated by the standard deviation (17.1%) and the coefficient of variation (22.2%). In general, different microtopographic types exerted different influences on soil moisture behavior. The plane surface presented the largest average soil moisture values and the smallest spatial variability. The lowest soil moisture values were observed in the ridge, mainly due to the rapid drainage of these areas. Although pipe woodland region can concentrate surface runoff during and after rainfall, the larger trees growing in these areas can lead to increased soil moisture evapotranspiration. [ABSTRACT FROM AUTHOR]

Abstract: Questions: Does restoration management of a formerly afforested blanket bog lead to the vegetation, and the environmental conditions it indicates, becoming similar to intact bog? Location: A 147‐ha blanket bog in Scotland's Flow Country, afforested in the 1980s but undergoing restoration since 1998. Methods: Vegetation in the restoration area was surveyed in nine, 1.6–6.4‐ha plots, in 1998, 2003 and 2011. Each plot was matched to nearby plots that were either intact bog or remained afforested. Principal Response Curves were used to highlight the main axes of vegetation variation and test whether plant community trajectories in the restoration area differed from intact bog. The following restoration outcomes were assessed: floristic similarity to bog vegetation; and moisture, fertility and acidity, as inferred from vegetation using Ellenberg indicator values. Results: In the 6 years after restoration began, vegetation developed towards bog‐like conditions. In the subsequent 8 years, overall vegetation change stalled, and spatial variability increased, reflecting diverging trajectories in wetter and drier parts of the site. Ellenberg's F‐values implied significant re‐wetting in the restoration area, reaching moisture levels similar to intact bog. Other restoration outcomes progressed in wetter microsites and areas (furrows and flat ground), but stalled in drier locations (plough‐ridges and steeper slopes). Conclusions: Overall moisture conditions, as indicated by plants, have recovered. However, restoration progress has stalled in drier areas, where additional management may be needed. Long‐term vegetation monitoring has helped clarify barriers to recovery and the management needed to overcome them. The value of such monitoring schemes in guiding restoration should be reflected in their wider implementation, within an adaptive management framework. [ABSTRACT FROM AUTHOR]

Fine-resolution Light Detection and Ranging (LiDAR) data often exhibit excessive surface roughness that can hinder the characterization of topographic shape and the modeling of near-surface flow processes. Digital elevation model (DEM) smoothing methods, commonly low-pass filters, are sometimes applied to LiDAR data to subdue the roughness. These techniques can negatively impact the representation of topographic features, most notably drainage features, such as headwater streams. This paper presents the feature-preserving DEM smoothing (FPDEMS) method, which modifies surface normals to smooth the topographic surface in a similar manner to approaches that were originally designed for de-noising three-dimensional (3D) meshes. The FPDEMS method has been optimized for application with raster DEM data. The method was compared with several low-pass filters while using a 0.5-m resolution LiDAR DEM of an agricultural area in southwestern Ontario, Canada. The findings demonstrated that the technique was better at removing roughness, when compared with mean, median, and Gaussian filters, while also preserving sharp breaks-in-slope and retaining the topographic complexity at broader scales. Optimal smoothing occurred with kernel sizes of 11−21 grid cells, threshold angles of 10°−20°, and 3−15 elevation-update iterations. These parameter settings allowed for the effective reduction in roughness and DEM noise and the retention of terrace scarps, channel banks, gullies, and headwater streams.