Grassland Restoration Research Articles

Dominant drivers of vegetation changes in key ecological barrier of northeastern Tibetan Plateau since 2000: Human impacts or natural forces?

Human activities and natural forces have profoundly influenced vegetation ecosystems in the Tibetan Plateau over the recent decades. However, contributions of these two driving forces to vegetation changes remain controversial, especially in the ecological barriers like the Qilian Mountains (QM) in the northeast where many protecting measures and strategies were applied to enhance ecosystem stability and services. Our study employed a process-based model and a multi-perspective assessment method to determine dominant drivers of vegetation changes in the QM since 2000. The result indicated that human activity changes contributed 40.74% to the significant vegetation amelioration of the QM as a whole, which is comparable to natural forces. Areas dominated by human activity changes accounted for 18.42% of the entire region, which were mainly distributed in grassland restoration area, oasis agricultural area and forestry protection area. In these areas, increased human activities (including desertified grassland restoration, agricultural irrigation and fertilization, forest protections and afforestation) mainly promoted the vegetation amelioration. Yet, natural forces resulted in amelioration in partial alpine grasslands in southeastern QM, accounting for 10.53% in area. Areas dominated by both human activity changes and natural forces, mainly in grazing grasslands, accounted for 47.80%. Variations in grazing intensity and climate jointly determined fluctuations in vegetation therein. Additionally, there remained 23.25% areas lack of obvious drivers, generally with sparse vegetation. Ecological protections and agricultural measures significantly promoted the vegetation amelioration of the QM since 2000. The findings could provide essential insights for protection and construction of the ecological barriers in the Tibetan Plateau.

Effects of Manipulated Rainfall and Intraspecific Variation Within Dominant Species on Community Assembly: Insights From a Long‐Term Grassland Restoration Experiment

ABSTRACTGrasslands converted to agricultural land use can be reestablished by sowing seeds of native species and temporal dynamics of diversity under altered climate can inform community assembly in the context of global change. We quantified three aspects of diversity (species richness, phylogenetic diversity, and functional diversity) in restored prairie plots sown with different ecotypes of two dominant grass species and manipulated rainfall to understand the relative importance of abiotic filtering and population source of dominant species on community assembly. We also evaluated the contributions of intra‐ and interspecific variations in functional traits across plots sown with different ecotypes of dominant species. Since the fourth year of community establishment, species richness decreased over time as dominant species gradually established. Phylogenetic and functional diversity was unaffected by the ecotypic sources of dominant species during restoration. Experimental drought did not affect species richness, phylogenetic, or functional diversity. Community structure in the grasslands was mainly shaped by intraspecific, within‐population variation in the dominant species rather than by differences in traits among species. Our results showed that intraspecific biotic interactions contribute more than environmental filtering to community assembly in a tallgrass‐dominated prairie ecosystem.

Quantitative Analysis of Human Activities and Climatic Change in Grassland Ecosystems in the Qinghai–Tibet Plateau

Net primary production (NPP) serves as a critical proxy for monitoring changes in the global capacity for vegetation carbon sequestration. The assessment of the factors (i.e., human activities and climate changes) influencing NPP is of great value for the study of terrestrial systems. To investigate the influence of factors on grassland NPP, the ecologically vulnerable Qinghai–Tibet Plateau region was considered an appropriate study area for the period from 2000 to 2020. We innovated the use of the RICI index to quantitatively represent human activities and analyzed the effects of RICI and climatic factors on grassland NPP using the geographical detector. In addition, the future NPP was predicted through the integration of two modeling approaches: The Patch-Generating Land Use Simulation (PLUS) model and the Carnegie–Ames–Stanford Approach (CASA) model. The assessment revealed that the expanded grassland contributed 7.55 × 104 Gg C (Gg = 109 g) to the total NPP, whereas the deterioration of grassland resulted in a decline of 1.06 × 105 Gg C. The climatic factor was identified as the dominant factor in grassland restoration, representing 70.85% of the total NPP, as well as the dominant factor in grassland degradation, representing 92.54% of the total NPP. By subdividing the climate change and human activity factors into sub-factors and detecting them with a geographical detector, the results show that climate change and anthropogenic factors have significant ability to explain geographic variation in NPP to a considerable extent, and the effect on NPP is greater when the factors interact. The q-values of the Relative Impact Contribution Index (RICI) and the RICI of the land use change NPP are consistently greater than 0.6, with the RICI of the human management practices NPP and the evapotranspiration remaining at approximately 0.5. The analysis of the interaction between climate and human activity factors reveals an average impact of greater than 0.8. By 2030, the NPP of the natural development scenario, economic development scenario (ED), and ecological protection scenario (EP) show a decreasing trend due to climate change, the dominant factor, causing them to decrease. Human activities play a role in the improvement. The EP indicates a positive expansion in the growth rate of forests, water, and wetlands, while the ED reveals rapid urbanization. It is notable that this is accompanied by a temporary suspension of urban greening.

From lawns to meadows: spiders (Arachnida: Araneae) as indicators to measure urban grassland restoration success

In the present study, we investigate how spiders can be used to assess the effectiveness of restoring mesic grasslands on former urban lawns. We compile and analyze a comprehensive dataset, including both past and current data, focusing on the Aachen region. By systematically examining this data, we identify various indicators using different analytical methods. This approach allows us to distinguish distinct species communities, making them useful as diagnostic tools at various stages of habitat development. Additionally, we identify further parameters that are essential for evaluating meadow restoration in urban settings. We highlight the crucial importance of understanding the local species repertoire, as this knowledge is vital for setting realistic benchmarks for restoration projects.

Effect of Caragana microphylla Lam. on Desertified Grassland Restoration

Background: The restoration of the degraded sandy grasslands in Hulun Buir is crucial for maintaining the local ecological balance and sustainable development. Caragana microphylla Lam., a shrub species widely employed in the restoration of sandy vegetation. It is essential to understand its impact on the understory vegetation and soil properties during this process. Methods: This study employed ANOVA, Pearson correlation, and redundancy analysis to systematically analyze the impact of C. microphylla on the three critical stages of desertified grassland vegetation recovery: semi-fixed dunes, fixed dunes, and sandy grasslands. It provided strategies for the restoration of desertified grassland vegetation and offered additional theoretical evidence for the role of vegetation in promoting the recovery of sandy lands. Results: (1) As the degree of vegetation recovery in desertified grasslands increases, the species richness of understory vegetation, Shannon–Wiener index, community height, and biomass also increase. Both the community height and biomass within shrublands are higher than outside, with species richness within the shrublands being higher than outside during the semi-fixed and fixed-sand land stages. (2) In both the 0~10 cm and 10~20 cm soil layers, soil water content showed an increasing trend, peaking in the sandy grassland stage (1.2%), and was higher within the shrublands than outside. The soil water content at 10~20 cm was higher than in the 0~10 cm layer. In both layers, clay and silt content gradually increased with the degree of vegetation recovery in the sandy land, and higher within the shrublands than outside, while the opposite was true for sand content. (3) In both soil layers, soil organic carbon gradually increased with the degree of vegetation recovery, peaking in the sandy grassland stage (4.12 g·kg−1), and was higher within the shrublands than outside. Total nitrogen increased from the semi-fixed-sand land stage to the fixed-sand land stage, with higher levels within the shrublands than outside at all stages. Soil pH within the shrublands decreased as the degree of vegetation recovery increased. There was no significant change in the total phosphorus content. (4) In both soil layers, soil physicochemical characteristics accounted for 59.6% and 46.9% of the vegetation changes within and outside the shrublands, respectively, with the main influencing factors being the soil particle size, total nitrogen, soil water content, and soil organic carbon. Conclusions: In the process of sandy grassland restoration, C. microphylla facilitates the growth and development of vegetation by enhancing the underlying soil physicochemical properties, specifically regarding the soil particle size distribution, soil water content, soil organic carbon, and total nitrogen.

Less hay collected at more dates: toward successful restoration of subtropical grasslands by hay transfer

Hay transfer is a promising method to restore temperate and subtropical grasslands, but its efficiency may depend on the harvesting timing and amount of hay used. We evaluated effects of harvest date (mid‐spring/November, early summer/December, and mid‐summer/February) and hay quantity (500 and 1000 g/m2) on vegetation cover, species richness, and species composition in an experimental study in subtropical southern Brazil for a period of 2 years. We transfer undried hay from a well‐conserved reference area onto a former grassland site degraded by pine plantations. Hay harvested during mid‐spring and early summer led to higher soil cover and species richness compared to the mid‐summer hay treatment in the first year of the experiment. A drought spell decreased vegetation cover in the second year following the hay transfer, with the mid‐spring hay treatment being the least affected. C3 grasses were more effectively introduced by mid‐spring and early summer hay, in contrast to C4 grasses that were better introduced by mid‐summer hay. Lower quantities of hay tended to lead to higher cover and species richness for all harvest dates. Freshly cut undried hay can be an effective way to reintroduce native species in degraded subtropical grasslands. We conclude that timing of hay collection and the amount of hay used influence vegetation cover and species composition at the restoration site and that multiple harvest dates increase restoration success. The drought in the second year of the experiment illustrates the need to consider the possibility of adverse climatic conditions in restoration planning.

Effects of short-term nitrogen addition on the recovery of alpine grassland in the Tianshan Mountains of Xinjiang, China.

The restoration of alpine grasslands has garnered significant attention across various sectors. Historically, natural restoration has been the primary approach for grassland recovery, characterized by its prolonged duration. To expedite the recovery of degraded grasslands, it is essential to identify the limiting factors of restoration, enabling efficient and rapid recovery. Appropriate nitrogen (N) addition levels have been considered a potential strategy to enhance the recovery of grassland ecosystems and augment their ecological benefits. However, the effectiveness of N addition in alpine grassland restoration remains debated. This study investigated the impact of five N addition levels (CK: control [0 g/m2]; LN: low N [5 g/m2]; MN: medium N [10 g/m2]; HN: high N [15 g/m2]; SN: severe N [20 g/m2]) and two experimental approaches (N addition once per year [NPY] and three times per year [NTY] at the same dosages) on plant and soil properties and the maximum restoration capacity of alpine meadows. Our findings reveal three key insights: The level of N addition was the primary factor influencing aboveground plant biomass and coverage. Plant diversity decreased under the NTY regime and increased with NPY in the Bayinbruck grassland. N addition significantly altered soil properties, including pH, salinity, soil organic carbon (SOC), soil-available phosphorus (AP), and soil total phosphorus (TP). Notably, soil TP, total nitrogen (TN), and AP substantially impacted plant community structure and diversity. Based on structural equation model (SEM) and analysis of variance (ANOVA), optimal grassland restoration was achieved with the HN (15 g/m2) treatment under NPY and the MN and HN (10 and 15 g/m2) treatments under NTY. Overall, our study offers crucial insights into the conservation, management, and restoration of grassland ecosystems on the Bayinbruck Plateau. It underscores the significance of N addition effects on plant communities, vegetation restoration, and soil properties.

Variation Patterns and Affecting Factors of Plant Alpha Diversity, Beta Diversity and Its Components in Restoration Grasslands on Loess Plateau

ABSTRACTUnderstanding spatiotemporal variation in diversity and identifying key external affecting factors are essential for biodiversity conservation. However, community assembly and species diversity in natural grassland (NG) restoration on the Loess Plateau remain unclear. In this study, we examined α diversity (species richness), β diversity (βtotal), and its components (βrepl and βrich) across 89 grassland communities, which were categorized into five restoration stages: recent grassland (RG), early restoration (ER), middle restoration (MR), later restoration (LR), and NG. Linear mixed models (LMM) were used to analyze the effects of topographic, soil, and landscape factors on diversity. Results showed that α diversity followed an increasing‐decreasing trend across restoration stages (7–21 species m−2), peaking at the MR stage. In contrast, β diversity and its two components declined with duration, with βtotal and βrepl being notably higher in ER than in LR and NG. Differences in βtotal primarily resulted from species replacement (βrepl, 61%–70%), with a smaller contribution from species gain and loss (βrich, 30%–39%). The LMM also revealed that restoration stage was the most important factor affecting plant diversity, explaining 59.3%, 68.4%, 53.5%, and 58.8% of richness, βtotal, βrepl, and βrich, respectively. In comparison, landscape had weaker effects on diversity (17.2%, 24.2%, 46.5%, 39.8%), while topography and soil factors had the least effects. In summary, deterministic processes (restoration stage) dominate natural restoration, but substantial differences persist between restoration grassland and NG. This study provides valuable insights for assessing restoration progress, prioritizing conservation areas, and informing future grassland management in semi‐arid and fragmented regions.

Responses of plant and microbial C:N:P stoichiometry to livestock removal

Livestock removal (LR) is considered an effective strategy for recovering ecosystem functions in degraded grasslands. Carbon (C), nitrogen (N), and phosphorus (P), as well as their ratios in plants and microorganisms, act as key regulators of ecosystem stability and nutrient limitation during grassland succession. However, few studies have comprehensively evaluated plant and microbial nutrient limitations through C:N:P stoichiometry following LR over different durations. Here, our study explored the C, N, P contents, and C:N, C:P and N:P ratios of green and senescent leaves, microbial biomass and extracellular enzymes after 33 years of LR on the Loess Plateau, China. The results showed that LR increased the C, N, and P contents of plant and microbial communities. LR (>26 years) enhanced C, N, P contents of green leaves by 364.7 %, 232.2 %, 134.6 %, and C, N, P contents of senescent leaves by 164.8 %, 230.8 %, 86.3 %, respectively. LR also increased plant C:P and N:P ratios and the P reabsorption efficiency, indicating that the plant communities shifted from N to P-limitation during grassland restoration. Compared with the grazing sites, LR26 increased C, N, P contents, C:P and N:P ratios of soil microbial biomass, whereas reduced soil N-acquiring enzyme activity and enzymatic N:P ratio, indicating that the microbial community experienced higher P limitation than that of grazing sites. Plant and microbial communities showed strong plastic relationships with soil resource. Vegetation cover and productivity played strong roles in altering the plant and microbial C:N:P stoichiometry following LR. These findings indicate that long-term LR (>26 years) will exacerbate plant and microbial P limitation during grassland succession.

Effects of Long-Term Fenced Enclosure on Soil Physicochemical Properties and Infiltration Ability in Grasslands of Yunwu Mountain, China

Fenced enclosures, a proven strategy for restoring degraded grassland, have been widely implemented. However, recent climate trends of warming and drying, accompanied by increased extreme rainfall, have heightened soil erosion risks. It is crucial to assess the long-term effectiveness of fenced enclosures on grassland restoration and their impact on soil physicochemical properties and water infiltration capacity. This study investigated the effects of enclosure duration on soil organic matter, aggregate composition and stability, and infiltration capacity in Yunwu Mountain Grassland Nature Reserve, comparing grasslands with enclosure durations of 2, 14, 30, and 39 years. Results showed that grasslands enclosed for 14, 30, and 39 years had infiltration rates increased by 20.66%, 152.03%, and 61.19%, respectively, compared to those enclosed for only 2 years. After 30 years of enclosure, soil quality reached its optimum, with the highest root biomass, soil organic matter, aggregate stability, and a notably superior infiltration rate. The findings suggest that long-term fenced enclosures facilitate grassland vegetation restoration and enhance soil infiltration capacity, with the most significant improvement observed at the 30-year enclosure milestone, followed by a gradual decline in this effect.

Classification Model of Grassland Desertification Based on Deep Learning

Grasslands are one of the most important ecosystems on earth, and the impact of grassland desertification on the earth’s environment and ecosystem cannot be ignored. Accurately distinguishing grassland desertification types has important application value. The appropriate grazing strategies can be implemented based on these distinctions. Grassland conservation measures can be tailored accordingly. This contributes to further protecting and restoring grassland vegetation. This project takes color images labeled with the desertification types of grasslands as the research object, uses the currently popular deep learning model as the classification tool, and then establishes a color image-based grassland desertification classification model based on the feature extraction network, based on the Vision Transformer model, by comparing the various deep learning image classification models. The experimental results show that, despite the complex structure and large number of parameters of the grassland desertification classification model obtained in this project, the test accuracy rate reaches 88.72% and the training loss is only 0.0319. Compared with the popular classification models such as VGG16, ResNet50, ResNet101, DenseNet101, DenseNet169, and DenseNet201, and so on, the Vision Transformer demonstrates clear advantages in classification accuracy, fitting ability, and generalization capacity. By integrating with deep learning technology, the model can be applied to grassland management and ecological restoration. Mobile devices can be used to conveniently capture image data, and information can be processed quickly. This provides efficient tools for grazing managers, environmental scientists, and conservation organizations. These tools assist in quickly assessing the extent of grassland desertification, optimizing grassland management and conservation decisions. Furthermore, strong technical support is offered for the ecological restoration and sustainable management of desertification grasslands.

Natural grassland restoration exhibits enhanced carbon sequestration and soil improvement potential in northern sandy grasslands of China: An empirical study

Vegetation restoration is an effective measure for restoring degraded ecosystems. Soil carbon mineralization, a crucial indicator for evaluating the effectiveness of vegetation restoration, is essential in soil carbon cycling. However, the response of soil carbon mineralization to different vegetation restoration types remains unclear. In this study, grassland (Leymus chinensis and Stipa bungeana), shrubland (Corethrodendron fruticosum), and forestland (Ulmus pumila) with 20 years of consistent restoration in the Xilingol sandy grassland were selected to determine the effects of vegetation restoration types on soil carbon mineralization. The results showed that the soil cumulative carbon dioxide emissions (CCE) and microbial respiration rate (SMR) in grassland and forestland were significantly higher than those in shrubland, while soil carbon mineralization efficiency (CME) and microbial metabolic quotient (MQ) were significantly lower than those in shrubland. Furthermore, soil organic carbon (SOC) and its fractions were influenced considerably by vegetation restoration types, with grassland exhibiting the highest SOC content. The ratios of soil total effective nutrients (C/N, N/P, and C/P) and the content of active organic carbon (DOC, MBC, EOC, and POC) can effectively reflect the changes in soil carbon mineralization and the stability of SOC pools. The variations in CCE were influenced by litter biomass, macroaggregates organic carbon, mineral-associated organic carbon (MAOC), and dissolved organic carbon (DOC), while the changes in SMR were affected by aboveground biomass (AGB), soil total nitrogen and phosphorus ratios (N/P), and microaggregate organic carbon and microbial biomass carbon. The changes in CME were affected by AGB, N/P, pH, MAOC, and DOC, while the changes in MQ were influenced by AGB, N/P, DOC, MAOC, and easily oxidizable organic carbon. Given the higher carbon sequestration benefits and soil quality improvement capability of naturally restored grassland, this study suggests that grassland could be considered the primary vegetation restoration type in the Xilingol sandy grassland.

Mixed-cultivation grasslands enhance runoff generation and reduce soil loss in the restoration of degraded alpine hillsides

Abstract. Vegetation restoration is among the most effective measures for controlling runoff and soil erosion resulting from human activities. Nevertheless, few studies have been undertaken to analyze the effects of grassland restoration on maintaining local runoff, especially on alpine degraded hillsides where mixed-cultivation grasslands predominate. In this research, runoff plots were established to investigate the impact of three mixed-cultivation grasslands, each sowing two grass species per plot on a 20° slope: Deschampsia cespitosa and Elymus nutans (DE), Poa pratensis L. cv. Qinghai and Elymus nutans (PE), and Poa pratensis L. cv. Qinghai and Deschampsia cespitosa (PD). The activation and volume of surface runoff and the magnitude of soil loss on alpine degraded hillsides over 3 years (2019, 2020, and 2022) were assessed. A severely degraded meadow (SDM) plot was used as a control. The findings indicated that mixed-cultivation grasslands can effectively maintain runoff and reduce soil loss as planting age increases. Between 2019 and 2022, the values of the average runoff depth for DE, PE, PD, and SDM were 0.47, 0.55, 0.45, and 0.27 mm, respectively. Despite the increase in runoff, grassland restoration favored soil conservation: the net soil losses per unit area of SDM were 1.4, 1.3, and 1.9 times greater than those in DE, PE, and PD, respectively. The key factors affecting soil loss and runoff were rainfall amount, duration, and intensity (60 min intensity). We conclude that the results of this study can serve as scientific guides to formulate efficient policy decisions for planning the most effective vegetation restoration in severely degraded hillside alpine meadows. To improve the effectiveness of grassland restoration, we suggest that protective measures should be prioritized during the initial planting stage of cultivated grasslands.

Stronger influences of grassland growth than grassland area on hydrological processes in the source region of the Yellow River

Concerns about regional hydrological responses to land use cover changes have arisen worldwide. However, the separation and quantification of the effects of changes in vegetation area and growth status on hydrological processes remains unclear. Here, we applied a distributed hydrology soil vegetation model (DHSVM) to analyze how the grassland growth state and surface area influence hydrological processes in the source region of the Yellow River (SRYR). The results showed that although the grassland surface area decreased slightly from 1981 to 2020, grassland growth (represented by the leaf area index) tended to increase from 2000. Grassland changes (including area and growth status) increased soil moisture storage and evapotranspiration to an overall extent of 2.03 % and 5.66 %, respectively; and most of the increase occurred after 2000 by 2.90 % and 9.40 %, respectively. These processes under grassland change led to an overall decrease in runoff of 2.41 %, with a much stronger decrease after 2000 of 4.3 %. Changes in grassland growth accounted for ∼95 % of the runoff variations caused by grassland changes in the SRYR during the 40-year study period, compared to changes in grassland surface area. Simulations assuming different extents of grassland degradation suggest that such degradation can reduce evapotranspiration and soil moisture storage, thereby increasing runoff, whereas grassland restoration has the opposite effect. Our results highlighted the sensitivity of hydrological processes in the SRYR to grassland growth and the need for appropriate interventions to maintain and restore grasslands.

Grassland restoration on linear landscape elements – comparing the effects of topsoil removal and topsoil transfer

Artificial linear landscape elements, including roads, pipelines, and drainage channels, are main sources of global habitat fragmentation. Restoration of natural habitats on unused linear landscape elements can increase habitat quality and connectivity without interfering with agricultural or industrial development. Despite that topsoil removal and transfer are widely applied methods in restoration projects, up to our knowledge these were previously not compared in the same study system. To address this knowledge gap, we compared spontaneous vegetation recovery after the elimination of positive (embankments) and negative landscape scars (drainage channels) in lowland alkaline landscapes in South Hungary. The novelty of our study is that we compared the fine-scale and landscape-scale results of both methods. At the fine scale, we monitored the spontaneous vegetation development on the created open surfaces in the first, second and fourth year after restoration in 160 permanent plots per year. For characterizing the habitat changes on the landscape scale, we prepared habitat maps and assigned naturalness scores to each patch before and after the restoration activities. Both restoration methods resulted in a rapid vegetation recovery at the fine scale, progressing toward the reference state. In the topsoil removal treatment, a large part of the soil seed bank was removed; therefore, the colonization of the bare surface was a slower process. Seeds of halophytes, including the endemic and protected Suaeda pannonica, were probably present in the deeper soil layers, and these species became established in the restored surfaces, despite being absent in the surrounding vegetation. For restoring vegetation cover, topsoil transfer was a more rapid option; however, vegetation closure and competition by generalist species and weeds hampered the establishment of target species. The removal of the landscape scars by both methods made the sites accessible for grazing. At the landscape scale, the two methods had different effects: there was a slight increase in the habitat naturalness in the topsoil removal site, and a slight decrease in the topsoil transfer site because of weed encroachment. Spreading an upper layer of nutrient-poor soil with low amounts of weed seeds, direct propagule transfer, and targeted grazing regimes could enhance restoration success.

Monitoring invasive exotic grass species in ecological restoration areas of the Brazilian savanna using UAV images

Identifying and monitoring invasive exotic grasses (IEG) is critical for the ecological restoration of grasslands and savannas, as they are the main barrier to the successful recovery of native grasslands and savannas. The integration of high-resolution remote sensing data, acquired through UAVs (Unmanned Aerial Vehicles), with machine learning algorithms is advancing restoration monitoring. The present study aimed to estimate IEG cover and identify plots with different invasive species dominance in ecological restoration areas in the Brazilian savanna. For ground truth, species cover estimates were carried out in plots through point-line intercept sampling. Then, the areas were classified according to the dominance of each invasive species (>40% vegetation cover) or of a mix of native species. A multispectral camera onboard a UAV was used to acquire images in the visible to near-infrared spectrum. From the images, vegetation indices and texture metrics were derived as predictor variables. The Random Forest (RF) algorithm was used to estimate the percentage of invasive species cover and to classify plots in terms of species dominance. The final RF regression for invasive species cover percentage presented an R2 of 0.71 and selected the blue band, NIR and Ratio Vegetation Index (RVI) as the most important variables. The overall accuracy of plot classification according to species dominance was 84%. The most prominent predictors were the Green Chlorophyll Index (GCI), the atmospherically resistant vegetation index (ARVI), and the RVI. The structural and photosynthetic characteristics of exotic and native species influenced the spectral responses. In conclusion, multispectral images acquired with UAV can be used to estimate the proportion of invasion in restoration sites and to map areas dominated by different invasive grass species in grasslands and savannas. This is a useful tool for evaluating restoration success and can help indicate areas that require management interventions.

Disembedding and Disentangling Grassland Valuation: Insights into Grassland Management Institutions and Ecological Research in China

After two decades of implementing top-down grassland restoration projects focused on reducing livestock numbers and pastoralist populations, the Chinese government’s well-funded efforts have not significantly reversed grassland degradation. This study reviews the institutional changes in grassland management over the past forty years, highlighting the Livestock and Grassland Double Contract Household Responsibility System of the early 1980s and the Grassland Ecological Reward and Compensation Policy introduced in 2011. It demonstrates how these institutional transformations have shaped pastoralists’ evolving understanding of grassland value and reveals that commodifying grassland’s economic and ecological value has led to the capitalization of nature, disembedding husbandry from grassland production, and undermining the effectiveness of conservation projects. This article also showcases the development of grassland ecology research in China, noting its increasing detachment from a holistic understanding of ecosystems and the interdisciplinary needs of management practices. The disjunction between grassland ecology research and practical management has resulted in a lack of techniques aligned with local ecological and socioeconomic contexts. This article champions active engagement with and protection of pastoralist communities to reintegrate grasslands’ true economic and ecological value into management practices, thereby effectively restoring degraded grasslands and achieving sustainable management.

Grazing exclusion enriches arbuscular mycorrhizal fungal communities and improves soil organic carbon sequestration in the alpine steppe of northern Tibet

Fencing for grazing exclusion is regarded as a traditional and effective method for the natural restoration of degraded alpine steppe, and it effectively promotes plant growth and enhances soil carbon stocks. Arbuscular mycorrhizal fungi (AMF) are essential microorganisms in grassland that play a major role in plant-derived C translocation into the soil. However, the effects of fencing on AMF communities and their contributions to soil carbon sequestration are still unclear. In this study, alpine steppe areas with three different fencing durations (free grazing, medium-term fencing for 5-6 years and long-term fencing for more than 10 years) in the northern Tibetan Plateau were selected to explore the effects of grazing exclusion on AMF communities and their roles in soil carbon sequestration. The results showed that medium- and long-term fencing significantly increased both plant aboveground biomass and soil organic carbon (SOC) content. The AMF community composition varied significantly during different fencing durations, with a dramatic increase in the relative abundance of Glomus but a significant reduction in the relative abundance of Diversispora with longer fencing time. Medium-term fencing significantly increased AMF richness and the Shannon-Wiener index. Meanwhile, fencing significantly increased hyphal length density (HLD), glomalin-related soil protein (GRSP) and the proportion of macroaggregates (250-2,000 μm), all of which contribute positively to SOC. Structural equation modeling revealed that fencing time positively influenced HLD and the AMF community composition, subsequently affecting T-GRSP, which was tightly correlated with SOC. Our findings suggest the potentially important contribution of AMF to SOC sequestration, so more attention should be paid to AMF during alpine steppe fencing, particularly for enhancing the efficiency of degraded grassland restoration efforts.

Linear relationships between aboveground biomass and plant species diversity during the initial stage of degraded grassland restoration projects.

The relationship between aboveground biomass and plant diversity has been extensively examined to understand the role of biodiversity in ecosystem functions and services. Degraded grassland restoration projects can enhance carbon sequestration. However, the relationship between biomass and diversity remains one of the most actively debated topics regarding grassland ecosystems in degraded grassland restoration projects. We speculated that establishing the linear relationships between aboveground biomass and plant species diversity could contribute to enhancing the efficacy of degraded grassland restoration projects. This study sought to determine whether these relationships were linear during the initial stages of the restoration projects of degraded grasslands in Xing'an League, China. The investigations were based on an examination of seventy-six 1 × 1 m2 plots distributed among 15 areas in which the degraded grassland was at the initial stages of restoration. To quantify the species diversity of the degraded grassland communities, we used the species richness, Shannon-Wiener, inverse Simpson's reciprocal, and Pielou's evenness indices. Our analyses revealed that aboveground biomass had clear positive linear relationships with species richness during the initial stages of degraded grassland restoration. However, there were less pronounced associations with species diversity as assessed using the Shannon and inverse Simpson indices, based on regression models. Furthermore, weed biomass was found to have significant negative effects on species richness and Pielou's evenness. The weak linear relationship between aboveground biomass and species richness could be ascribed to an increase in weed biomass. We concluded that aboveground biomass and plant species diversity could be enhanced during the initial stages of degraded grassland restoration projects and suggest that the extent of weed biomass could serve as a key indicator of the efficacy of restoration from the perspective of plant species diversity and aboveground biomass in carbon sequestration projects.

Scale dependency of taxonomic and functional diversity in pristine and recovered loess steppic grasslands

Widespread campaigns on forest restoration and various tree planting actions lower the awareness of the importance of grasslands for carbon sequestration and biodiversity conservation. Even lower attention is given to the conservation of biodiversity and ecosystem functioning in remnants of ancient, so-called pristine grasslands. Pristine grasslands generally harbour high biodiversity, and even small patches can act as important refuges for many plant and animal species in urbanised or agricultural landscapes. Spontaneous succession of grassland is frequently viewed as a cost-effective tool for grassland restoration, but its applicability is strongly dependent on many local to landscape-scale factors, and the recovery is often slow. It is therefore essential to monitor the success of grassland restoration projects that rely on spontaneous succession. We compared the species diversity and functional attributes of pristine and recovered grasslands by studying the taxonomic and functional diversity in thirteen (8 pristine and 5 recovered) loess steppic grasslands using differently sized sampling plots from 0.01 to 100 m2. Our results indicate that there are remarkable differences in taxonomic and functional diversity between pristine and recovered grasslands. We also found that during secondary succession there is a likely functional saturation of the species assembly in the first few decades of recovery, and while patterns and structure of recovered grasslands became quite similar to those of pristine grasslands, species richness and diversity still remained much lower. Pristine grasslands support considerable plant diversity, and species composition is slow to recover if destroyed by agricultural land use. This underlines the importance of preserving existing pristine grassland remnants, which might serve as sources of species for future restoration measures.