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Soil nitrification, driven by ammonia‐oxidizing archaea (AOA) and ammonia‐oxidizing bacteria (AOB), is a crucial process in maintaining the soil nitrogen (N) balance. However, the influence of AOA and AOB on soil gross nitrification rates (GNR) in response to vegetation restoration remains unclear, particularly in karst regions. In this study, we investigated soil GNR and the abundance, diversity, and community composition of AOA and AOB across after vegetation restoration. Four land use types were examined: plantation forest (PF), forage grass (FG), a combination of plantation forest and forage grass (FG), and cropland (CR, control). Soil ammonium N (NH4+) was higher in the vegetation restoration compared to that in cropland, whereas nitrate N (NO3−) exhibited the opposite trend. Soil GNR were reduced by 55.4%–90.3% in the vegetation restorations compared to that in cropland. The abundance, Chao1, and Shannon index of AOB were lower in vegetation restorations compared to cropland, respectively. The abundance and diversity of AOA were higher than those of AOB but were unaffected by vegetative restoration. Furthermore, AOB community is more sensitive to vegetation restoration than AOA community. Specifically, the abundance of AOB taxa belonging to the genera Nitrosospira and Nitrosovibrio was decreased by the restoration efforts. In addition, soil nutrients availability (e.g., NH4+, NO3−, and phosphorus) and AOB index (e.g., Shannon index) were the main factors driving soil GNR. This study highlights the importance of AOB in driving soil nitrification during vegetation restoration and emphasizes the necessity to optimize soil nitrogen management in karst ecosystems. [ABSTRACT FROM AUTHOR]

Ecological restoration projects have significantly increased global vegetation cover and reduced soil erosion. However, it is very challenging to clarify the complex soil erosion mechanisms of limestone and dolomite in the southwest karst region and to identify the key factors affecting erosion. The study site has a subtropical monsoon climate with precipitation concentrated during the rainy season from May to September. In this study, four plantation restoration measures with a recovery time of approximately 16 years were selected, which included arbor forest, orchard, grassland, and cropland (control). Soil physical–chemical properties and soil erodibility K values were used to evaluate the soil erosion characteristics. The results showed that both limestone and dolomite exhibited lower soil bulk density as well as higher capillary porosity, and soil water‐stable aggregates after revegetation. The limestone and dolomite K values were reduced by 12%–15% and 15%–17%, respectively. However, the K value of limestone was 17.9% higher than that of dolomite, indicating that dolomite exhibited a higher stability. Through redundancy analysis and structural equation modeling, revegetation was found to reduce soil erosion by influencing the soil particle composition. The silt was the key factor influencing soil erosion, accounting for 84.4% and 78.2% of the variation in the limestone and dolomite K values, respectively. These findings suggest that vegetation restoration enhances soil erosion resistance; however, the effectiveness of restoration is controlled by the lithology in the southwest karst region. These findings provide a reference for soil and water management and vegetation restoration. [ABSTRACT FROM AUTHOR]

In the Loess Plateau, gaining insights into the water storage and soil retention functions of diverse vegetation types, especially, in the semi‐arid watersheds is crucial for identifying the key factors necessary to ensure sustainable development and achieve land degradation neutrality. In this study, five different land use types such as forest, shrub, artificial grass, and natural grasslands were surveyed from 2014 to 2020. Meanwhile, bare land was also used as a control plot. The trade‐off between erosion mitigation and water consumption indicator was quantified based on the ecosystem services perspective benefits. Our results showed that there are significant differences among different land use types (p < 0.05): natural grassland > shrubs > artificial grassland > forests. Vegetation restoration was able to change the soil particle size distribution, increasing clay and silt content, and decreasing sand particles. During the growing season, surface soil water storage decreased in all land use types coinciding with the higher decrease in the control plot. The change in surface water storage in the forest was the most stable, with a decrease of 0.13 mm. The trade‐off between erosion mitigation and water consumption indicator was less than 0 for all vegetation types, which indicates a synergistic effect on soil conservation and water storage benefit. Our results demonstrated that shrubs can register the most balanced benefit of water storage and soil preservation. This is a solid basis for the selection of specific vegetation types and the optimization of the watershed landscape in the middle reaches of the Yellow River, characterized by vulnerable areas due to aridification. [ABSTRACT FROM AUTHOR]

Given the developmental program outlined in United Nations Sustainable Development Goal 15 (Life on Land) and the to effectively address the challenge of biodiversity decline while mitigating the adverse effects of climate change, particularly drought, on terrestrial forest ecosystems, a fundamental reorientation of global forest restoration paradigms is warranted. It is imperative to move beyond a narrow emphasis on expanding forest area and instead prioritize the enhancement of biodiversity and functional attributes within these ecosystems. However, the differential response mechanisms of forest ecosystem functional communities and main plant functional types (PFTs) to environmental factors, especially soil and topography, remains unclear, especially at plant level. Here, we divided the functional communities of 93 sites in the study area into seven groups through Two‐way indicator species analysis (TWINSPAN), and studied the different functional communities, namely dynamic succession, species richness, and PFT compositional differences. We also analyzed the various PFTs and functional community response mechanisms to soil and topographic factors using canonical correspondence analysis (CCA). The main results were as follows: (1) With the successional stages of PFTs, vegetation diversity across multiple functional communities inceased, tree and shrub proportions and importance increased, while herbs decreased. (2) From the arid and barren areas (i.e., G2), to the humid and fertile areas (i.e., G6 and G7), various compositional PFT differences, and their responses to soil and topographic factors, were found, namely, xerophytic, annual and biennial species gradually changed to mesophytic, hygrophytic, and perennial species (richness increased 6.94 ~ 27.33%, important value (IV) increased 8.73 ~ 29.45%) for shrubs and herbs. (3) Functional communities in various successional stages display distinct sensitivities to soil and topographic factors, as evidenced by a notable increase in the richness and IV of deciduous broad‐leaved tree species, rendering their communities more responsive to SOC and AS, whereas evergreen coniferous trees (e.g., Pinus tabuliformis Carr.) were sensitive to altitude (AL) and exhibited a tendency to transition from plantations to natural secondary forests predominantly at higher altitudes (above 1200 m). Our findings suggest that site conditions influence scenarios, and that different PFT responses and adjustments to soil and topography factors affect whole functional community dynamic succession processes, which can profoundly impact forest ecosystem function predictions based on PFT changes in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]

Precise assessment of soil organic carbon (SOC) storage requires understanding how vegetation and soil physico‐chemical properties differ in SOC fractions. Therefore, we aimed to analyze the dynamics of aggregate‐associated, labile organic carbon (LOC) fractions corresponding to depth to clarify the effect of vegetation and soil properties on water stable aggregate (WSA) mineral adsorption in subtropical, red soil with five vegetation restoration regimes. The results showed that the large macro‐aggregate fraction dominated the degraded red soil, which had the highest content of dissolved organic carbon (DOC). WSA‐associated, easily oxidized organic carbon (EOC) varied from 6.26 to 20.02 g/kg and was not affected by vegetation types. Schima superba pure forest significantly increased DOC (0.38 g/kg on average) and particulate organic carbon (POC, 7.92 g/kg on average), which had the highest biomass. Along with soil depth, WSA‐associated POC declined, while exhibiting a growth trend with decreasing particle size, for example, the highest POC was found in <0.053 mm aggregates. The redundancy analysis ordination indicated that soil porosity and total nitrogen (TN) were the main soil parameters that explained the most variance. Meanwhile, the vegetation biomass, except for litter, were all significantly positively correlated with <0.053 mm aggregates. Leaf biomass played the most important role on DOC in macro‐aggregates with a 53.42% contribution. For aggregate‐related POC, the largest contribution was from the interactions between branch biomass and pH (47.78%) followed by TN (35.1%) of micro‐aggregate‐related POC. Leaf biomass, <0.053 mm aggregates, and TN can be used as indicators to evaluate the impact of vegetation restoration on WSA‐associated SOC fractions. Broad‐leaved forest or in combination with indigenous coniferous species was a better choice for SOC sequestration improvement in the study area for managing C supply, process, and flux in subtropical terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Vegetation restoration in ecologically fragile areas has a significant carbon sequestration (CS) effect. However, it is usually difficult to achieve quantitative assessment at the regional scale for this part of human activity intervention. The Chinese government's ex‐situ poverty alleviation and relocation (EPAR) project has relocated approximately 10 million people from areas with a fragile ecological environment to urban centralized resettlement, which is a typical case of weakened environmental intervention by human activities (Guizhou Province accounting for approximately 20% of the total relocated population in China). The CS model of vegetation photosynthesis and spatial analysis of geographic information were used to quantify the contribution of human activities to the natural restoration of vegetation CS, based on the data of net primary productivity (NPP) of vegetation from 2000 to 2020. The results show that the implementation of the EPAR project acts as an external force to drive vegetation restoration and CS, which increases the slope of the carbon density change trend (from k = 30.9 to k = 57.41), resulting in an overall carbon density increase of 26.51 tCkm−2. The regional spatial analysis showed that the correlation coefficients between carbon density and relocation intensity in the 5‐year and 10‐year change were r = 0.976 (p < 0.01) and r = 0.949 (p < 0.05), respectively, indicating a significant positive correlation. Based on this, the CS contribution of vegetation in 84 districts in Guizhou Province that implemented EPAR projects was calculated, showing that 79 districts contributed positively, accounting for 94%. The average contribution of CS by vegetation restoration in each district was 0.0556 Tg, and offset CO2 emissions were 0.2059 Tg. The other five districts with a negative contribution to CS were distributed in regions with relatively stable ecosystems and mature forests. This shows that human intervention in the environment changes more significantly in fragile ecological areas. [ABSTRACT FROM AUTHOR]

Restoring vegetation and constructing check dams are important measures for controlling water erosion in slope‐gully systems. However, percolation through the dam body could lead to shortened runoff paths in the gully. Moreover, the synergistic effects of vegetation patterns and siltation‐induced runoff path length decrease (RPLD) in slope‐gully systems on reducing water erosion remain unclear. In this study, 20 physical models of slope‐gully systems were constructed to quantitatively evaluate the synergistic effect of these measures under simulated rainfall. The models included four slope vegetation patterns (no vegetation, up‐slope, middle‐slope, and down‐slope) and five levels of RPLD in the gully (0, 1, 2, 3, and 4 m). Owing to synergistic effects, combined measures led to a more considerable reduction in soil and water loss than a single measure. Furthermore, the synergistic effect was related to vegetation patterns and shorter siltation‐induced runoff paths. The mean synergistic effect produced the following runoff yield order: down‐slope (2.84%) > middle‐slope (2.81%) > up‐slope (1.78%); and 4 m (3.18%) > 3 m (2.66%) > 2 m (2.29%) > 1 m (1.78%). The sediment yields were in the following order: down‐slope (18.15%) > middle‐slope (12.63%) > up‐slope (6.67%), and 4 m (14.56%) > 3 m (12.82%) > 2 m (11.73%) > 1 m (10.82%). These results suggest that revegetation of the lower parts of the slope, along with check dams, will be more effective for controlling soil erosion. Such synergistic effects should be considered in future soil erosion modeling. [ABSTRACT FROM AUTHOR]

Vegetation restoration is an important means for regional climate change mitigation and terrestrial carbon sequestration. However, large‐scale vegetation restoration in arid and semiarid regions can excessively consume local water resources, thus threatening regional water supply safety. To explore the impact of vegetation restoration on the water–carbon relationship in the Loess Plateau in China before and after the implementation of the Grain‐for‐Green Program (GfGP), the regional hydro‐ecological simulation system (RHESSys) model was used to simulate the temporal and spatial evolution of key variables of the water cycle, including the actual evapotranspiration (ET) and the surface runoff (Rs), and that of the carbon cycle, including the net primary productivity (NPP) and the total carbon density (TC). In addition, statistical methods were applied to analyze the interaction between water and carbon cycles. Results show that the RHESSys model is capable of simulating the key ecohydrological elements. In the period of 1990–2019, ET and NPP both showed significant increasing trends at rates of 8.9 mm yr−1 and 6.9 g C m−2 yr−1, respectively. The TC also had a slightly increasing trend, with rates of 0.04 t C hm−2 yr−1 (land‐use in 1995), 0.07 t C hm−2 yr−1 (land‐use in 2005), and 0.08 t C hm−2 yr−1 (land‐use in 2015). In contrast, Rs decreased at the rate of 0.35 mm yr−1. As for spatial distribution, in the middle and southeastern parts of the Yanhe River basin with the vegetation well‐restored, ET, NPP, and TC showed significant increasing trends, while the Rs showed a decreasing trend. ET was also found to have a positive correlation with NPP and TC, while the Rs has a negative correlation with NPP and TC. Moreover, the correlation of Rs‐NPP and Rs‐TC was found to increase after the implementation of the GfGP, which indicates the reinforcing effect of vegetation restoration on the water–carbon trade‐off relationship. Therefore, it is critical to coordinate and regulate the interaction between water consumption and runoff in the context of vegetation restoration in the Yanhe River basin, as well as to promote the synergy between regional ecological restoration and social economic development for water security. [ABSTRACT FROM AUTHOR]

The Grain‐for‐Green Program in China aims to restore sloping karst cropland severely degraded by intensive agriculture to secondary forest. Heterotrophic respiration (Rh) is a major process of carbon release from soils and is associated with the sequestration of soil organic carbon (SOC). However, we still do not have a comprehensive understanding of Rh and what drives it along soil profile horizons during the natural vegetative recovery process in typical karst soils. We investigated the responses of Rh (C release per gram of soil) and specific Rh (C release per gram of SOC) in soil horizons from the soil surface to bedrock at the different vegetation recovery stages in a karst region. Coincident soil microbial properties (e.g., bacterial and fungal abundance, total microbial biomass, potential enzyme activities) and physicochemical properties were quantified. Vegetation restoration after cropland abandonment significantly increased Rh rates due to increased soil nutrients and microbial biomass, bacterial abundances, and hydrolase activities (all, p < 0.05). The rates of Rh enhanced in sloping cropland (SC) from the soil surface to bedrock but reduced in the recovering stages (ASC: abandoned sloping cropland and SF: secondary forest) and primary forest (PF). The specific Rh between SF (1.34 mg CO2‐C g−1SOC d−1) and PF (1.32 mg CO2‐C g−1SOC d−1) were not significantly different but both of them were greater than those in SC (0.79 mg CO2‐C g−1SOC d−1) and ASC (0.8 mg CO2‐C g−1SOC d−1). Soil physicochemical properties and microbial properties explained approximately 48% and 22% of the variations in Rh along vegetation recovery, respectively. Nitrogen to phosphorus stoichiometry exerted the most direct and positive effects on Rh, suggesting the importance of managing soil nutrient status to regulate carbon decomposition during vegetation recovery in karst soils. The increased microbial biomass was the most important microbial factor regulating Rh in later vegetation recovery phases. Our results provide scientific insight into the impact of vegetation restoration on Rh in degraded ecosystems, which is important for reducing carbon loss in karst soils. [ABSTRACT FROM AUTHOR]

Vegetation restoration is one of the most effective ways to increase soil organic carbon (SOC). After the implementation of vegetation restoration policies such as the Grain‐for‐Green Program, which has increased regional vegetation coverage. However, the impact of land use, vegetation types, restoration time, and topographic and meteorological factors on SOC remains unclear. Therefore, this study examined the effect of vegetation restoration on SOC in the Loess Plateau through a meta‐analysis of 520 sample data collected from 60 research papers. The results showed that vegetation restoration in the Loess Plateau significantly increased SOC by 29.40%. Restoration time was the most important factor affecting the SOC after revegetation. Land use type was an important factor that influenced SOC; the most significant impact on SOC was found when the previous land use type was abandoned land and the current land use type was woodland. Different vegetation types resulted in different SOC as follows: Fagaceae > Salicaceae > Pinaceae > Leguminosae. Broad‐leaved forests had significantly higher SOC than that of coniferous forests. Non‐nitrogen‐fixing plants increased SOC significantly compared to nitrogen‐fixing plants. SOC decreased in 0–5 years after vegetation restoration, and then increased with the increase of restoration years. Especially, the soil carbon sequestration effect of vegetation has been significantly improved after 10 years of restoration. [ABSTRACT FROM AUTHOR]

Vegetation restoration potential (VRP) mapping provides important information for ecosystem restoration planning. However, the inappropriate assumption of traditional models that VRPs are identical within an individual similar habitat unit may result in low accuracy of VRP maps. This study proposes an improved data‐driven model, namely, the similar habitat and machine learning‐based VRP mapping (SHMLVRPM) model. This new model introduces a variety of machine‐learning models to mine information on geographical environment heterogeneity in areas of similar habitat, which helps to improve the accuracy of VRP maps. Taking Yan'an City, Shanxi Province, China as our study area, we demonstrate the modelling process and validate the model. Our results show that the SHMLVRPM model can effectively construct high‐accuracy VRP maps, and its information entropy is approximately 5.8 greater than that derived from the traditional models. The random forest method has the highest prediction accuracy (R2 = 0.8) among the tested machine‐learning methods. The average VRP value of Yan'an is approximately 68%; counties with the low VRP achievement are concentrated in the northern part of Yan'an, only 54%. Our research results can assist policymakers in optimizing vegetation restoration options and promoting the protection and sustainable development of fragile ecosystems. [ABSTRACT FROM AUTHOR]

China's Grain‐for‐Green Program (GFGP) motivates conversion from steep slope cropland to forest or grassland to reverse serious land degradation. However, impoverished farmers potentially persist with inefficient slope farming for survival, thereby threatening the sustainable GFGP efforts. Consequently, a strategy for balancing farming and vegetation restoration from a spatial optimization perspective is necessary. Here, we selected two catchments with high and low agricultural intensity in the loess hilly and gully regions for a case study. Spatial analysis and binary logistic regression models were used to clarify the effects of topography, accessibility, and location factors on cropland distribution and explore spatially optimized cropland distribution. The results show that steep slope cropland is still widespread, of which cropland with slopes >15° accounts for 46.7% and 34.7% in the two catchments, respectively. Residences and roads significantly impact steep slope cropland distribution, and around 80% of cropland with slopes >15° is distributed within 200 m from residences or 100 m from roads. In cropland redistribution scenarios, cropland with slopes >25° and >15° can be redistributed to gentler slopes while maintaining cropland areas in catchments with high and low agricultural intensity. Correspondingly, 38.8% and 81.2%, respectively, of simulated cropland on gentle slopes needs optimized attributes such as accessibility in order to be priorities of farmers. Our research provides new insights into GFGP strategies for steep slope cropland restoration in catchments with different agricultural intensities, thereby advancing sustainable farming and vegetation restoration in China's mountainous regions. [ABSTRACT FROM AUTHOR]

Although the influence of mechanical sand control techniques on vegetation on degraded sand dunes has received much attention for a long time, our understanding of the underlying processes of plant community formation is not yet strong. Analyses of trends in the turnover and nestedness components of beta diversity can be informative of the process of response to sand dune stabilization. In this study, we applied a field investigation of sand dunes at different stabilization stages in northern China. We then used Baselga's method to calculate total beta diversity and partition it into spatial turnover and nestedness to clarify the underlying community change processes. Our study indicated that the implementation of straw checkerboard techniques significantly increased the beta diversity of the community, leading to species heterogeneity. Species turnover was the main contributor to species beta diversity, and it was caused by high environmental heterogeneity with sand dune stabilization. The contribution of the nestedness component to beta diversity decreased with dune stabilization, indicating that with stabilization, dissimilarity was largely driven by variation in community composition rather than differences in taxonomic richness. This study provides insights into the underlying variation in species composition among sites where mechanical sand fixation engineering has been implemented and important guidelines for combating desertification. [ABSTRACT FROM AUTHOR]

Desertification is a worldwide problem caused by climate change and human activity in dryland regions. In China, approximately 27% of the land surface is desertified. In these desertified ecosystems, aboveground interactions are known to greatly affect ecological succession, but belowground soil microbial communities are relatively unstudied. It is not yet clear how these communities change with different vegetation patch types (e.g., shrub vs. grass) across successional stages in dryland ecosystems. In this study, we assessed the effects of shrub patches (dominated by Artemisia ordosica) and grass patches on soil microbial community diversity, soil environment, and soil substrates across three successional stages (mobile, semi‐mobile, and fixed dunes) in a sand dune ecosystem in the Kubuqi Desert, China. Microbial alpha diversity, as indicated by the Shannon index or operational taxonomic unit (OTU) richness, was not affected by patch type but increased with successional stages. Patch type‐ or successional stage‐induced changes in soil bacterial and fungal alpha diversity were mainly associated with soil organic carbon. Unlike alpha diversity, soil microbial beta diversity was greatly affected by successional stage and patch type. The Mantel test revealed that changes in soil bacterial beta diversity were mainly associated with soil organic carbon, and changes in soil fungal beta diversity were mainly associated with soil organic carbon and soil pH. Microbial OTU richness responded more strongly to the successional stage than the microbial Shannon index, indicating that microbial OTU richness can be used as an indicator of successional status in desert ecosystems. The consistent differences in microbial beta diversity between shrub and grass patches across the three successional stages indicate that shrubs significantly influence soil microbial communities in desert ecosystems. [ABSTRACT FROM AUTHOR]

Vegetation restoration can exert a profound influence on surface soil characteristics, which likely plays a significant role in the evolution of soil erodibility. This study was conducted to quantify the effects of vegetation restoration on the soil erodibility of carbonate‐derived laterite in karst areas. Experiments were conducted at two representative sites for different years of vegetation restoration. Six karst mountain land use types [grassland (Y1), shrubland (Y2) and woodland (Y3) in young forest (YF); forest trails (O1), shrubland (O2) and woodland (O3) in old forest (OF)]. A structural equation model and random forest regression analysis were applied to distinguish the key environmental factors dominating soil erodibility. The results showed that the soil erodibility K factor exponentially decreased with increasing restoration age and tended to remain stable after 20 years (y = 0.0466 + 0.0316e−0.2889x, R2 = 0.98). The K factor in the OF decreased by an average of 2.1%–14.8% compared to those in the YF. A structural equation model indicated that vegetation restoration indirectly reduced soil erodibility by altering plant growth and coverage and its associated soil property changes. A random forest regression analysis of global datasets indicated that soil erodibility is mainly affected by topographical factors (i.e., latitude, elevation and slope), and their mean decrease accuracy values (IncMSE) exceeded 20%. Both forestland and shrubland were not considered as the most important factors for affecting global soil erodibility. Conversely, grassland, cropland and bare land were among the important factors. These results could guide the potential benefits of vegetation restoration strategies to meet soil conservation and ecosystem function goals in karst mountain ecosystems. [ABSTRACT FROM AUTHOR]

Soil water, nitrogen, and organic matter contents are among the main limiting factors for successful vegetation restoration on degraded slopes in arid and semi‐arid areas. Combining slope engineering measures for revegetation is considered an effective eco‐rehabilitation practice used to restore degraded slopes. However, a single slope measure is insufficient to efficiently utilize runoff and sediments to improve soil water, nitrogen, and organic matter for revegetation. In this study, four treatments were implemented on a hilly slope in a temperate continental semiarid area slope engineered with fish‐scale pits (semicircle‐shaped pit, 1.0 m in diameter, 0.5 m in radius, and 0.2 m deep), namely: with gravel mulching (GM), straw mulching (SM), infiltration hole (IH), and without other measures (CK). The effects of the combined measures on soil water, nitrogen, and organic matter contents were analyzed over 4 years. The results showed that the soil water storage (0–100 cm) showed no significant differences among all treatments; however, the soil (100–260 cm) of GM/SM/IH treatment increased by 11.65%/8.62%/7.10% compared with CK (p < 0.05). The soil organic matter and nitrogen (0–100 cm) under IH were 73.34%/81.29%/98.32% and 77.37%/80.27%/85.31% higher than CK/SM/GM, respectively (p < 0.05). Overall, IH is the most effective measure for increasing nitrogen and organic matter, and it is equally effective with GM and SM to increase the water replenishment of deep soils in semiarid areas. Our findings provide the combined measures to combat soil water, nitrogen, and organic matter deficits for slope revegetation in arid and semiarid areas. [ABSTRACT FROM AUTHOR]

The significant increase in vegetation coverage in northern China over the past two decades has attracted worldwide attention. Revegetation has been completed via artificial and natural restoration techniques, and the relative performance of each needs to be further explored. Although some studies have focused on the comparison between artificial and natural methods in vegetation restoration from a micro‐perspective, there is a lack of evidence at the regional scale. This study considers Wuqi County and its adjacent areas of the Loess Plateau in northern China as our study area. First, natural and artificial restoration areas were identified. Then, the restoration sustainability of different restoration strategies and the adjustment effect of climate factors in the relationship between vegetation restoration strategy choice and vegetation restoration sustainability were analyzed. We found that the vegetation restoration strategies employed varied between local jurisdictions. In areas dominated by artificial restoration, vegetation coverage increased over a short period, but the growth rate diminished in the long term. In comparison, in areas mainly dominated by natural restoration, although the growth rate of revegetation was not very high in the short term, it was stable in the long term. In addition, the impact of vegetation restoration strategies on vegetation restoration sustainability exhibited spatial heterogeneity, and the temperature, humidity, and wind speed further affected strategy outcomes. This study provides a new perspective for vegetation restoration strategy evaluation and is expected to serve as a reference for the optimization of relevant ecological policies in the future. [ABSTRACT FROM AUTHOR]

Desertification and the expansion of deserts are regarded as a major threat to human livelihoods and ecosystem services, as well as achieving Sustainable Development Goals. Humans have been recognized as significant agents in the expansion of desert‐like conditions, through the agency of desertification/land degradation, and through contributions to global climate change. Yet, how desertification changes and whether human or climate change drives these processes and trends over the whole Mongolia Plateau is still not clear. Here we first use MODIS data for 2000–2019 to assess the long‐term vegetation changes across the Mongolian Plateau, both in Inner Mongolia of PR China and the Mongolian People's Republic. We then appied a General Linear Model to analyze the additional climate and human attribute data sets to explore relationships between the observed desert extent reduction and their potential drivers. Results show that from 2000–2019, desert extent declined by over 7%, comprised of an almost 11% reduction in Inner Mongolia and 5% reduction in Mongolia, and a reduction in the degree of desert conditions, as measured by vegetation cover grades, across the whole region (37.5% decline ‐ one grade in PR China, 28.75% in Mongolia). The majority of desert area reduction occurs in the northern and eastern areas of the Mongolia Plateau. We found that the main drivers of changing desert extent is not because of a reduction in human pressures on the land, but an increasing trend of both precipitation and temperature, which explains over 75% of all the observed changes. Besides, urbanization, and a reduction of population pressures on the land, contribute to most of the remaining changes. Our results suggest that although the climate has been the primary driver of changing desert area and severity, human interventions have played an important role, although the way it intervenes and the intensity varies in Inner Mongolia and Mongolia. Human's active response to land degradation in the desert contributes to more land restoration in Inner Mongolia than in Mongolia. [ABSTRACT FROM AUTHOR]

Water erosion affects soil carbon (C) loss and C enrichment in deposited sediment. To better understand the dynamics of water erosion and topsoil C loss with sediments after vegetation restoration, we studied the sediment yield from each rainfall event over two growing seasons (June through October) in four runoff plots with different vegetation covers (Robinia pseudoacacia, Spiraea salicifolia, Stipa bungeana, and bare soil) in an eroding soil landscape on the Chinese Loess Plateau in 2016 and 2017. The results showed that the C loss in the deposited sediments was reduced by 99.0 ± 0.5% when the soil was vegetated compared to bare soil. Decreased organic C enrichment ratios were shown under the vegetation cover (2.14 ± 0.68 for tree cover, 1.34 ± 0.20 for shrub cover, and 1.63 ± 0.26 for grass cover) compared to bare soil (2.65 ± 0.99). The decreasing organic C enrichment ratios were affected by the fractional vegetation coverage and soil organic C concentration. During organic C enrichment in the bare soil, the additional particulate organic C or mineral‐associated organic C were based on the C enrichment ratio. The results can improve our understanding of C enrichment processes under different vegetation covers and help predict the C enrichment ratio in a vegetation restoration area. [ABSTRACT FROM AUTHOR]

Vegetation restoration has been proposed as an effective measure for rehabilitating degraded land and slowing desertification in arid regions. However, the spatial variation in soil quality and plant diversity following vegetation restoration remains unclear. This study was designed to explore soil nutrient dynamics and how soil nutrients affect plant diversity and spatial heterogeneity after shrub restoration. We assessed the effect of Haloxylon ammodendron (C.A.Mey.) Bunge (which has been planted over 30 years) on the soil nutrients and plant diversity in a desert–oasis ecotone in Minqin County, Gansu, China, using geostatistics, beta diversity and rarefaction analyses, and Hill number extrapolation. Soil nutrients, including soil organic matter, total nitrogen, and alkali nitrogen, increased significantly after H. ammodendron planting. Species richness gradually increased from 1–5 years to 10–20 years after H. ammodendron was planted but then decreased at 20–30 years. The largest differences in plant composition were observed at 15 and 20 years. Plant diversity increased in the whole 30 years after shrub planting, increasing in the first 25 years and then decreasing at 26–30 year stage. The maximum coefficient of determination for the spatial heterogeneity model fit was 0.84 (25 years). The spatial heterogeneity in vegetation decreased with increasing soil available K content at 1–10 years. Our results suggest that planting shrubs can improve soil conditions and plant species diversity in desert–oasis ecotones and soil nutrients have a strong influence on plant diversity patterns and spatial heterogeneity following vegetation restoration. [ABSTRACT FROM AUTHOR]

Overexploitation of magnesium has caused serious environmental pollution, and the ecological restoration of magnesite mines has attracted increasing attention in China. The aim of this study was to assess the effects of phytoremediation with Robinia pseudoacacia (RP) on soil quality and microbial communities in magnesite mines. Here, soil samples were collected from restored areas (R. pseudoacacia), natural forest (NF), and unrestored areas (CK), and the soil microbial communities were assessed by Illumina high‐throughput sequencing. Phytoremediation with R. pseudoacacia could alleviate soil alkalization and contribute to the accumulation of soil nutrients. A total of 531,329 effective 16S rRNA and 596,344 valid Internal Transcribed Spacer rRNA gene sequences were obtained, which were classified into 30 bacterial and 12 fungal phyla. The predominant bacterial and fungal phyla were Proteobacteria and Ascomycota, respectively. Bacterial diversity indices of RP were higher than those of the CK, both of which were lower than those in the NF site. While, fungal Chao1 and ACE (abundance‐based coverage estimator) indices of RP were higher than those of the CK and even surpassed those in the NF site. Soil microbial communities significantly differed among different treatments, and the effects of soil factors on microbial communities were comprehensive and not determined by a single factor. Generally, these results indicated that phytoremediation with R. pseudoacacia could effectively improve the soil environment of the abandoned magnesium mine, which provide useful insights and practical references for the suitable species that would be planted on magnesite mine for restoration. [ABSTRACT FROM AUTHOR]

Plant community characteristics and functional traits may respond to soil erosion due to their high plasticity in varied environments. However, the linkages between plant functional traits and soil properties under erosion stress remain poorly understood, despite the fundamental role they play in controlling soil erosion. Here, we selected 50 plots on degraded land caused by long‐term water erosion representing three degrees of erosion that differed in terms of soil profile and erosion landform. We measured aboveground plant characteristics, root functional traits, and soil properties to explore their responses to the degree of erosion and to identify the main factors mitigating soil erodibility (Kr). The results showed that vegetation cover and root length density (RLD) were the plant variables that were most sensitive to the erosion stress. Topographic parameters strongly affected plant community characteristics (vegetation cover and litter mass) by favouring thicker soil layers and lower bulk densities, and soil texture strongly affected root functional traits (root mass density [RD] and RLD) by favoring lighter soils. Importantly, plant community characteristics and root functional traits were the main drivers of Kr mitigation through their mediation effects on a range of soil properties (e.g., soil organic matter, aggregate stability, and shear strength) during the restoration, and vegetation can still be efficient in maintaining and restoring soil functions, even on severely degraded land. Overall, these findings could guide restoration practices to meet soil conservation and ecosystem function goals in degraded ecosystems. [ABSTRACT FROM AUTHOR]

Vegetation restoration potential mapping (VRPM) is of great importance for regional ecosystem restoration planning after long‐term land degradation or short‐term disasters. However, there are some problems to be solved in the current models for evaluating the potential of vegetation restoration. First, the models for VRPM are mostly established based on a knowledge‐driven index system. Although this kind of model is logically rigorous, it relies too much on expert knowledge and is relatively inefficient, especially for large‐area vegetation restoration assessments. Second, because of the spatial heterogeneity, as well as the absence of important indicators, the traditional global‐based evaluation models are difficult to adapt to the entire study area. In this study, an improved data‐driven approach, that is, a sliding‐window based similar habitat potential model, is developed for VRPM. The advantages of the new model include: (a) it is more efficient in determining the importance of each influencing factor without resorting to expert knowledge; (b) it is more locally adaptive than the global model because it performs sample training, rule building, and vegetation restoration potential calculation in each current local window. We provide a case‐study to show the modeling process and result interpretation of the new model. [ABSTRACT FROM AUTHOR]

In this study, we aimed to provide a comprehensive insight into seedling and ramet recruitment at the community level on recent landslide scars (i.e., the sliding surfaces regarded as the most difficult zones of landslides to restore), which may cast new light on landslide ecology and enhance theoretical support for interventions on landslide restoration. Through seedling and ramet monitoring and adult surveying on 12 three‐year‐old landslide scars on the hilly and gullied Loess Plateau, China, we characterized seedling and ramet recruitment in terms of their trade‐offs, processes and amounts, and we also assessed compositional correspondence between the adult and young (all seedlings and ramets combined) layers. We found that when seedling recruitment was employed in tandem with ramet recruitment, which might maximize colonists' fitness. Moreover, seedlings and ramets emerged constantly and were followed by low mortality rates. However, there were problems of emergence limitation and constant death, and, as a result, seedlings and ramets remained at low densities. Therefore, there appeared to be a slow and limited recruitment process of plant colonists on the scars. In addition, there was a high degree of compositional uncoupling between the adult and young layers, implying future potential changes of plant communities driven by Poa sphondylodes Trin., Stipa bungeana Trin., Ixeridium sonchifolium (Maxim.) Shih, Astragalus discolor Bunge ex Maxim. and Artemisia scoparia Waldst. et Kit. on shady scars and I. sonchifolium (Maxim.) Shih on sunny scars. We also proposed that the first three species can be used to restore landslide scars in the study area. [ABSTRACT FROM AUTHOR]

The "Grain for Green Programme" was implemented in the 1990s as a solution to the extreme degradation of karst landscapes that cover one‐third of China, largely caused by decades of poorly managed intensive agriculture. The recovery of soil functions is key to the success of ecosystem regeneration of abandoned croplands where the carbon (C) and nutrient cycles have been severely perturbed by cultivation. However, an ecological 'tipping point' beyond which soil functions are unrecoverable in manageable timescales may have been passed in the fragile, subtropical karst ecosystem. The aim of this study was to use the activity of key enzymes for C, nitrogen (N), and phosphorus (P) acquisition in the soil as a proxy for the biological response to vegetation restoration after agricultural abandonment in a severely degraded karst catchment at the Karst Critical Zone Observatory in Guizhou Province. In 2016, a space‐for‐time approach was used to establish a chronosequence of vegetation recovery: sloping cropland < recently abandoned sloping cropland < shrubland < secondary (regenerated) forest < primary (natural) forest. Soils were sampled from the surface to the bedrock (up to 80‐cm depth) in each recovery phase. The activity of all enzymes in the top 0 to 30‐cm depth increased after abandonment and was positively correlated with soil nutrient and water contents. Nitrogen deficiencies were indicated by the reduced ratios of C‐ relative to N‐hydrolase activity and the increased ratios of N‐ relative to P‐hydrolase activity in the abandoned croplands and shrublands. Phosphorus deficiencies were indicated by the reduced ratios of N‐ relative to P‐hydrolase activity and C‐ relative to P‐hydrolase activity in the soils of the shrubland and secondary forest compared with the primary forest. Our results revealed that near‐to‐natural biological soil function was recoverable as vegetation naturally restored and suggested that the rate of recovery may be accelerated by managed nutrient amendments during the early stages after abandonment. This new information may help to inform the managed regeneration of degraded agricultural land in nutrient‐poor, subtropical environments. [ABSTRACT FROM AUTHOR]

A natural gas pipeline extends over a distance of 310 km in the Hebei Province of China and passes through various zones of natural vegetation, mostly wooded. Construction required a working width of about 40 m and a 1.4‐m‐wide trench to be dug to a depth of 2.4 m to enable the installation of a pipe with a diameter of 1,016 mm. The construction process had to manage an irregular configuration of terrain with steep slopes, varying degrees of instability, and a propensity for erosion and land degradation. To prevent potentially massive soil erosion and further deterioration of the affected environment, a comprehensive soil and water conservation plan was designed and implemented. A 3.25‐km‐long study area was selected in rugged hilly country and was divided into seven topographic zones, with slopes ranging from <10° to over 50°. Different soil and water conservation measures were adopted in each zone, including engineering measures, revegetation measures, and maintenance measures. One year after installation, trees planted in individual holes grew well in each zone and the vegetation cover on the slopes treated by hydroseeding exceeded 90%. In addition, run‐off and sediment yield on slopes were significantly reduced. These conservation measures were conducive to environmentally sustainable development and may serve as a scientific reference for ecological restoration and vegetation reconstruction in future pipeline construction projects in similar terrain. Furthermore, these measures also helped to ensure the safe operation of the pipeline and provided protection for people living and working along the pipeline route. [ABSTRACT FROM AUTHOR]

Open‐pit mining causes severe land degradation in Yunnan Province, Southwest China. Vegetation restoration on the degraded land with open‐pit mining is challenging due to great physical and chemical condition changes of the post‐mined landscape. In this study, we compared the vegetation community composition and environmental factors along three disturbance gradients (mining area, restoration area, and control area) in four typical open‐pit mine types (phosphate, zinc, tin, and iron sites). Nonmetric multidimensional scaling analysis revealed that there are significant differences in the vegetation communities along three gradients for these mine sites. Quality species were selected by indicator species analysis for vegetation restoration as follows: Chloris virgata Sw. and Artemisia princeps Pamp at the phosphate site; Coriaria nepalensis Wall., Artemisia princeps Pamp, and Picris hieracioides L. at the zinc site; Artemisia princeps Pamp at the tin site; and Panicum brevifolium L. at the iron site. Canonical Correspondence Analysis ordination and Monte Carlo permutation tests were further used to determine the effects of environmental factors on vegetation diversity. The results showed that Cd, As, Zn, Pb, TC, and altitude all had significant effects on vegetation diversity (P < 0.05). Additionally, we found that the integrated effects of these variables on vegetation were greater in the mining area than in the other two gradients based on the model with the lowest Akaike Information Criterion. These results suggest that any plans for vegetation restoration in open‐pit mining areas should take disturbance intensity, mine types, and critical environmental variables into account. [ABSTRACT FROM AUTHOR]

Afforestation brings lots of water‐related benefits, including reducing soil erosion and improving water conservation, simultaneously; it is considered to be a land use activity, which threatens water resources security. Characterizing the response of soil moisture to revegetation is important for the sustainability of water and plants on the Loess Plateau of China. In this study, we conducted a meta‐analysis of 1,262 observations from 66 published studies to evaluate the effect of land use on the soil moisture of forest, shrubland, and grassland regions at a depth of 5 m in different ecological zones of the Loess Plateau. The results indicated that (a) Soil moisture content (SMC) decreased after land use conversion in all three ecological zones and was inconsistent among different soil layers. (b) Except for other grassland species, changes in the response size for soil moisture were not significant among any tree species, including Pinus tabuliformis, Robinia pseudoacacia, other forest species, Caragana korshinskii, other shrubland species, and Medicago sativa. (c) Soil moisture changes varied with different restoration types and ages. (d) The change in response to precipitation was not significant, whereas the change in response to temperature was significant. In addition, the responses of the initial soil moisture levels exhibited a negative correlation with revegetation. These results indicate that it is vital for scientific afforestation in the Loess Plateau to complement local climate conditions and soil properties. [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) accumulation enhances carbon (C) sequestration and subsequently the restoration of degraded ecosystems, but the changes in soil N properties after vegetation restoration in such ecosystems are poorly understood. We collected data from 358 fixed points in the karst catchment in China to determine the trends, magnitude, and mechanisms of soil N sequestration after 10 years of revegetation. The revegetation types were tillage fields that were abandoned or were converted to pasture, planted forest, or converted to mixed pasture and forest and pasture lands that were abandoned (P_Aban) or converted to mixed pasture and forest (P_Mix). The changes in soil N density (g m−2) over time were insignificant, and only P_Aban, P_ Mix, and the overall catchment experienced significant increases in soil N concentration (g kg−1). Structural equation modeling indicated that bedrock exposure affected the change in soil N concentration (∆NC) and the soil N sequestration value (∆ND) via affecting the change in soil C concentration, by directly affecting bulk density, soil depth, and Ca2+. The soil C:N ratio increased significantly, and the increase in soil N was slower than that of C, suggesting a decoupling of soil C and N accumulation in the initial stage of revegetation. ∆ND was significantly related to the change in soil C:N ratio, indicating that the coupling between soil C and N may be constrained by insufficient soil N sequestration during revegetation. These findings suggest that the restoration of degraded karst ecosystems requires an increase in soil N input early during vegetation restoration. [ABSTRACT FROM AUTHOR]

The dynamics of biophysical regulations of carbon fluxes can have a major effect on an ecosystems' carbon budget. Only a handful of comprehensive assessments of such dynamics exist. To better understand the carbon cycle, we measured all major carbon flux by biophysical regulations including rainfall, runoff, infiltration, and sediment yield at eight runoff plots in an eroding soil landscape on the Chinese Loess Plateau, a typical vegetation restoration area for the region. Results show that topsoil carbon flux by infiltration into deep soil layers was the largest efflux from topsoil in plots with vegetation, followed by runoff and sediment carbon effluxes. On the contrary, the carbon flux by sediment was the largest efflux from topsoil in plot without vegetation, followed by infiltration and runoff carbon effluxes. Total topsoil carbon flux by biophysical regulations to the deep layer is about 71 ± 10% of the typical carbon sequestration rate in the region. Topsoil carbon sequestration capacity might be underestimated by up to 43 ± 3% if the infiltrated carbon was not factored into estimates. The results of this study improve understanding of soil carbon dynamics and expand the dynamic carbon replacement hypothesis; photosynthesis replaces not only lateral carbon lost by erosion but also vertical carbon lost by infiltration. [ABSTRACT FROM AUTHOR]

Desertification of arid and semiarid land is a severe environmental problem. Better understanding of the desertification process, in the context of changing climate and growing human activities, is essential for policy-making on desertification control strategies and land-use management in these environmentally sensitive areas. In this study, we analyze vegetation change and dune activity over the years 1981-2013 in Mu Us, a semiarid dune field in north-central China, using remote sensing techniques and geomorphic analysis. During this period, we have observed an increasing trend in vegetation greenness, indicated by the Normalized Difference Vegetation Index, which is consistent with the decreasing trend of the dune mobility index. Changes in dune morphologies in the study area indicate that dunes are being stabilized under vegetation growth, and this morphological change could potentially be used to detect the long-term trend in desertification. Based on a detailed analysis of both climatic and socioeconomic data, we found that the decadal changes in wind strength have significant impact on the long-term vegetation rehabilitation in the study area and that the short-term variations in vegetation growth are associated with interannual fluctuations in precipitation. Policy-driven, large ecological restoration projects implemented in recent decades can exert a positive impact on vegetation restoration, especially under favourable climatic conditions. This study implies that such climatic conditions may offer a window of opportunity for land regeneration in semiarid northern China. [ABSTRACT FROM AUTHOR]

Although the functions and characteristics of soil seed banks in topsoil layers have been described for various ecosystems, the spatiotemporal pattern of the seed bank in deep soil and its ecological implications for vegetation restoration of active sand dune have not been fully explored. In 2007 and 2008, seed densities with regard to dune position, soil depth and season were investigated on an active and a stabilized sand dune of northeastern Inner Mongolia, China. Seeds in the 0-10 cm topsoil layer accounted for 60% of total soil seed bank on the stabilized sand dune, while more than 40% of seeds were stored in the 50-100 cm layers on the active sand dune. Seed density declined significantly with soil depth on the stabilized sand dune, but it was relatively constant across the 0-100 cm soil profile on the active sand dune. Seed density fluctuated with soil depth on the active sand dune suggesting that seeds were either relocated upward or downward over time. Seeds of annual non-psammophytic species accounted for the majority of soil seed bank on the stabilized sand dune, while pioneer psammophytes contributed more to the soil seed bank of the active sand dune. Our data suggest that seeds in the deep soil layers of active sand dunes account for a large proportion of the whole soil seed bank. Because of the effect of wind erosion, seeds in deep soil could be gradually exposed to shallow soil layers and potentially contribute to population recruitment and vegetation restoration on active sand dunes. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Physical damage is one of the main factors that cause seedling mortality in many ecosystems. However, the impact of physical damage due to rainfall erosion on seedling mortality is seldom investigated. In this study, we ask the following question: how does rainfall erosion influence seedling damage and establishment in the Loess Plateau region of China? Seedling damage and establishment experiments under different patterns of simulated rainfall were conducted. The seedling damage rate, damage type and growth status were investigated. The seedling damage rate was influenced by rainfall intensity and duration and by the runoff volume. The mean damage rate of all three studied species did not exceed 15 per cent, and the highest damage rate of individual species under special rainfall events was approximately 30 per cent. The type of damage suffered by the seedlings of Sophora viciifolia (which produces large seeds) mainly took the form of striking down, whereas seedlings of Artemisia scoparia (which produces small seeds) suffered the highest rates of washing away among the three studied species. In the seedling establishment experiment, after 120 days with six rainfall events, S. viciifolia had the highest seedling establishment rate (80·1 ± 2·5 per cent), followed by Bothriochloa ischaemun (67·2 ± 2·2 per cent), and A. scoparia (28·1 ± 2·5 per cent). The seedling damage rate, damage type and establishment rate were also related to seed size. Whether physical damage to seedlings is a major factor limiting vegetation restoration in eroded environments requires further research. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Understanding the effects of land use change on soil properties is important for soil quality improvement and sustainable land use. In this study, six land use types including wasteland (WLD), cropland (CLD), abandoned land (ABD), artificial grassland (AGD), shrubland (SLD) and woodland (WOD) were selected to analyse the effects of land use types on soil nutrient in the Anjiapo catchment in the western part of the Loess Plateau in China. Significant differences were found in soil organic matter (SOM), total nitrogen (TN) and nitrate nitrogen (NON) (P < 0.01) between the six land use types. Our study also showed that land use types have different effects on soil nutrient storage, and vegetation restoration may improve soil nutrients and soil quality. While crop plantation can significantly decrease soil fertility, the trend can be reversed by cropland abandonment and afforestation. It is recommended that more C input, alternative cultivation practices, vegetation restoration and education and techniques training of local farmers could be used to improve soil conditions and to advance the sustainable land use and local development in the loess hilly area in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]