Grazing Exclusion Research Articles

Persisting effects of seed bed preparation and early grazing on plant communities in grassland restoration

Semi-natural mountain grasslands are species-rich and provide a wide range of ecosystem services, such as biomass production for livestock grazing and carbon sequestration. Land abandonment but also habitat destruction are threatening these ecosystems highlighting the need for restoration when degraded. The transfer of plant material containing seed collected at non-degraded reference sites is increasingly used for restoration but the appropriate methods to prepare the transfer and to manage the grassland afterwards are still under debates. This study aims at testing the effects of seed bed preparation by harrowing and livestock grazing on the establishment of transferred targets and community trajectories towards the reference system. In a previous study, first year seedling counts showed a positive effect of seed bed preparation and a marginally significant negative effect of grazing on the seedling recruitment of the transferred species. We asked whether the results on first year seedling densities translate into significant effects on plant cover and whether these effects on plant cover change in the following three years. Both grazing and harrowing effects on species establishment were tested using a full factorial split-plot experimental design on five replicate sites. Data on species richness and vegetation cover for both the whole plant community and the transferred species were analysed during four years after seed transfer. The cover of transferred species increased whereas their species richness remained unchanged. We found a weak positive effect of harrowing on total cover whereas grazing had no effect. Seed bed preparation by harrowing had a clear positive effect on transferred target species cover. The negative effect of grazing on first-year seedling recruitment of transferred target species turned into a positive effect in the fourth year. However, this effect was only apparent in the harrowed plots resulting in a significant grazing-by-harrowing interaction. The similarity of the plant communities to the reference increased from the first to the fourth year and this increase was stronger in grazed and harrowed plots. In conclusion, the results confirmed the positive effect of seed bed preparation on restoration by seed transfer and demonstrated that initial grazing exclusion is not needed in mountain grasslands of our study area.

Soil organic carbon and nitrogen sequestration following grazing exclusion on the Loess Plateau, China

Enhancement of soil organic carbon (SOC) and nitrogen (N) storage in degraded ecosystems is of great significance for improving soil quality and mitigating climate change. Grazing exclusion is an effective management practice to restore degraded ecosystems in drylands. However, the spatio-temporal dynamics and regulating factors of SOC and N sequestration in degraded ecosystems following grazing exclusion has not been clearly explored. Using synthesized data from 38 peer-reviewed publications, we investigated the rates of SOC (RSOC) and soil total N (RN) stock changes and their controlling factors following grazing exclusion in the Loess Plateau of China. Grazing exclusion significantly increased SOC and total N stock in most sites. The average RSOC was 0.57, 0.64 and 0.7 Mg ha–1yr−1 and the average RN was 0.033, 0.031 and 0.036 Mg ha–1yr−1 at 0–20, 20–40 and 40–60 cm soil depths, respectively. RSOC showed a Poisson function relation with the duration of grazing exclusion. RSOC and RN did not significantly change with mean annual precipitation, but they were negatively correlated with mean annual temperature at 0–20 cm. RSOC at each soil depth was positively correlated with altitude. The strong coupling relationship between RSOC and RN resulted in no significant change in the ratio of SOC to total N between grazing exclusion and grazing sites over time. The results show that altitude, age of GE and initial SOC and N contents rather than precipitation controls these processes in the Loess Plateau. Grazing exclusion promotes SOC and N sequestrations more than 30 years in the degraded lands of the Loess Plateau. The inherent increase of soil N would be beneficial to soil carbon sequestration during the recovery process.

Effects of Grazing Exclusion on Microbial Community Diversity and Soil Metabolism in Desert Grasslands

In this study, the effect of 14 years of GE exclusion in a desert grassland on soil microbial community diversity and metabolites was examined. GE changed the bacterial community structure, the alpha diversity of the bacterial community, and the total phosphorus (TP) and total potassium (TK) content in the soil. More specifically, the relative abundance of Actinobacteria, Proteobacteria, and Chloroflexi increased with GE. In contrast, the relative abundance of Acidobacteria was higher during grazing (G), so it is believed that soil bacteria adapt to environmental changes. Both amino acid and carbohydrate metabolism were enhanced, while lipid metabolism was decreased under GE. It was concluded that GE could trigger changes in both bacterial diversity and soil metabolites, increase the energy supply, and regulate ecosystem function. Consequently, GE would have positive effects on the restoration of desert grasslands by altering the soil microbial community. This work provides new insights into the response of soil microbes to GE.

Climate factors regulate the depth dependency of soil organic carbon under grazing exclusion in Chinese grasslands: A meta‐analysis

AbstractSoil carbon (C) is one of the most abundant C pools in terrestrial ecosystems, and its dynamics is highly dependent on soil depth. Grazing exclusion (GE) has proven to be a promising approach for enhancing C sequestration; however, the comprehensive analysis on the depth distribution of soil C and driving factors of soil C dynamics under GE are still lacking. This study collected data comprising 563 paired observations from 75 papers to analyze the distribution characteristics and the driving factors of soil organic carbon (SOC) changes with soil depth under GE in Chinese grasslands. The results showed that GE positively contributed to soil C sequestration, and the change range of SOC were higher (47.70%) in the subsoil (>20 cm) than in the topsoil layer (0–20 cm; 29.24%). Furthermore, SOC was influenced by GE duration, exhibiting an increasing trend and reaching its highest value at 13–15 years of GE, then remaining stable or slightly decreasing thereafter. Boosted regression trees (BRTs) showed that climatic factors were the primary determinants of SOC changes; however, the key drivers of SOC varied across different soil depths. Mean annual precipitation (MAP) was the key driver of topsoil C dynamics, accounting for 32.7% of the variance. In contrast, mean annual temperature (MAT) regulated the response of subsoil SOC to GE, explaining 48.23% of the variance. In addition, plant biomass was a significant factor influencing the depth distribution of soil C under GE, and its effect on SOC decreased with increasing soil depth. Our study provides evidence that the subsoil has a greater potential for C sequestration than the topsoil layer after GE, and future studies should consider deep soil C dynamics to accurately assess C sequestration in grassland ecosystems.

Petrography and geochemistry of the Permian-Triassic boundary interval, Kangjiaping section, South China: Implication for the drastic marine environment change

The Permian-Triassic transitional interval exposed well at Kangjiaping section, northwestern Hunan, South China, contains microbialites, oolitic and oncolitic limestones intercalated with vermiculate micritic limestones in the Lower Triassic overlying the uppermost Permian bioclastic limestones, which provides an excellent opportunity to study the environmental changes after the end-Permian mass extinction (EPME) and the origins and environmental significance of these various anomalous sediments. In this paper, we describe in detail the petrographic and geochemical characteristics of these anomalous sediments, together with the reconstruction of the marine environment after the EPME. The continental margin weathering was significantly enhanced after the EPME, indicated by the higher concentrations of terrigenous minerals, Th, Sc, Sr, and rare earth elements in the Lower Triassic carbonates than in the uppermost Permian bioclastic limestones. Indicators such as V/(V + Ni) and Ni/Co ratios suggest that the oxygen content of shallow seawater significantly decreased after the EPME. While, most samples from the Kangjiaping section preserve a negative cerium anomaly, indicating the shallow seawater was still oxygenated both before and after the EPME. In addition, the abnormally rapid carbonate precipitation rate indicates a supersaturation state with respect to calcium carbonate in the shallow seawater after the EPME, but the depth and salinity of seawater and climate indicated by different microfacies are still different. Under the setting of a rapid transgression after the EPME, the microbialites first deposited on the platform with the exclusion of grazers at the beginning of the Early Triassic, followed by the oncolites formed when the climate turned humid with a relative sea-level rise. The oolites were primarily deposited in an arid climate with a relative sea-level fall, and the salinity and hydrodynamics of seawater controlled the ooids’ grain sizes. In contrast, the (vermiculate) micritic limestones were mainly formed in a humid climate with a relative sea-level rising and more terrigenous inputs. Therefore, the periodic relative sea-level fluctuation and arid-humid climate alternations play a vital role in the evolution and repeat stacking of various microfacies in the Kangjiaping section.

Biome regulates the effects of long‐term grazing on soil microbial diversity

AbstractIntroductionLivestock overgrazing represents one of the most destructive uses of land in terrestrial ecosystems and threatens biodiversity. However, understanding the effects of livestock overgrazing on below‐ground soil microbial diversity is limited, despite soil microbes representing the majority of biodiversity and determining ecosystem functioning.Materials and MethodsTo investigate the effects of overgrazing on soil microbial richness, a long‐term grazing exclusion experiment was conducted at six sites including three meadow steppes and three typical steppes in northern China.ResultsOur results revealed that overgrazing decreased bacterial and fungal richness across temperate steppes in northern China, and the biome could regulate the overgrazing effects, especially for fungal richness. Specifically, the negative effects of overgrazing on microbial richness were highly significant in typical steppes while not significant in meadow steppes that contained higher plant diversity and precipitation. Partial least‐squares path model showed that overgrazing affected soil microbial richness in highly complex ways, and the affected pathways were different in meadow steppes and typical steppes. The direct negative effects of grazing and their indirect negative effects via soil properties resulted in a significant decrease in microbial richness in typical steppes. In meadow steppes, the indirect beneficial effects via plant attributes offset the direct negative effects of grazing. Consequently, the soil microbial community in meadow steppe resisted overgrazing disturbance.ConclusionOur study illuminates the complex and highly biome‐dependent grazing effects and pathways on soil microbiota and indicates that meadow steppe may be more resistant or resilient to human disturbance than typical steppe. These findings suggest that different grasslands might be managed differently considering their intrinsic characteristics to help biodiversity conservation. Moreover, future research should focus on the underlying mechanisms of grazing effects on soil microbial richness. Besides grazing‐induced plant and soil traits changes, other potential pathways could strongly influence soil microbial diversity.

Plant litter predicts the changing trajectories of plant communities following grazing exclusion

AbstractLitter decomposition is a key component of global biogeochemical cycles that affects the availability of soil nutrients for plant productivity. Significant variations in litter decomposability between plant taxa are attributed to diverse functional traits including litter quality, plant nutrient production, and nutrient resorption efficiency which should influence the ecological fitness of plants in the community. However, no reports to date have explored the relationships between litter decomposition and plant community dynamics, that is, plant succession and interspecific competition. We conducted a litter decomposition experiment that focused on 21 plant species in an alpine meadow. The litter decomposition rates of these species were compared with their initial litter quality and nutrient use efficiencies to examine whether the plant litter indicators of the community structures were altered following grazing exclusion. We found that among these 21 plant species, those with higher nutrient use efficiencies had a lower litter decomposition rate. Meanwhile, lower decomposition rates were correlated with higher plant importance values, and this correlation became stronger over time in plant communities following grazing exclusion, except for dominant species. Our results suggested that litter decomposability can be used to predict the changing trajectories of plant communities following grazing exclusion, except for dominant species.

Putting down roots: Afforestation and bank cohesion of Icelandic Rivers

AbstractRiparian vegetation is widely recognized as a critical component of functioning fluvial systems. Human pressures on woody vegetation including riparian areas have had lasting effects, especially at high latitude. In Iceland, prior to human settlement, native downy birch woodlands covered approximately 15%–40% of the land area compared to 1%–2% today. Afforestation efforts include planting seedlings, protecting native forest remnants, and acquiring land areas as national forests. The planted and protected nature of vegetation along rivers within forests provides a unique opportunity to evaluate the various taxa within riparian zones and the channel stabilizing characteristics of the vegetation used in afforestation. We investigated bank properties, sediment textures, and root characteristics within riparian zones along four rivers in forests in Iceland. Bank sediment textures are dominantly sandy loam overlying coarser textures. Undercut banks are common because of erosion of the less cohesive subsurface layer. Quantitative root data indicate that the woody taxa have greater root densities, rooting depths, and more complex root structures than forbs or graminoids. The native downy birch has the highest root densities, with <1 mm roots most abundant. Modeling of added bank cohesion indicates that willow provides up to six times and birch up to four times more added cohesion to the coarse sediment textures comprising stream banks compared to no vegetation. We conclude that planting and protecting the native birch and willow helps to reduce bank erosion, especially where long‐term grazing exclusion can be maintained.

Reversing habitat loss: An experimental test of the interactive effects of grazing exclusion and surface rock restoration on reptile conservation

Abstract Restoring structural elements of habitats and understanding how restoration interacts with environmental factors such as grazing management can be crucial for improving conservation outcomes in agricultural landscapes. Surface rock is a structural habitat type that is critical for a range of reptile species; yet, it is often poorly managed and protected. Using a Before/After, Control/Impact (BACI) design, we experimentally quantified the response of reptiles to surface rock restoration in an agricultural landscape, and tested whether its effects interacted with livestock grazing treatments to influence various reptile diversity measures. To implement our crossed factorial design, we added approximately 50 tonnes of rock and 1 km of grazing exclusion fencing across 10 sites in south‐eastern Australia. We found increases in the number of total reptile captures, total individuals and species richness when comparing rock addition plots to non‐rock plots. There was no significant overall grazing exclusion effect or interactive effect of grazing and rock treatment on reptile measures. Synthesis and applications. Our study provides experimental evidence that surface rock addition is an effective restoration method for reptiles in agricultural landscapes. We recommend that the addition of surface rock is prioritised as a restoration tool for reptiles, and that existing surface rock areas are protected from clearing.

Response of soil N dynamics to land‐use change and topographic position in a semiarid hilly grassland

AbstractLand‐use changes through grazing exclusion (GE) or grassland afforestation (GA) are common restoring practices in semiarid ecosystems, but whether GE and GA exert similar or distinct effect on soil nitrogen (N) dynamics in certain ecosystem is still unclear, particularly in areas with complex terrain. Here, seasonal patterns of soil net N mineralization rates and mineral N contents were characterized in a hilly grassland on the Loess Plateau, China. A fenced grassland, an afforested shrubland and a grazing grassland (reference) with three topographic positions (the top, the north slope, and the south slope) were selected. Results showed that GE decreased soil net N mineralization rates but increased mineral N contents, while GA did not affect these metrics. Furthermore, topographic positions changed the effects of GE, with greater increase of soil total mineral N and nitrate N on the north slope than those on the top and the south slop. Soil layers also changed the effects of GE, with greater decrease in soil net N mineralization rates and greater increase in total mineral N and nitrate N contents at 0–10 cm than those at 10–20 cm. However, there was no difference among three topographic positions or between two soil layers under GA. These results demonstrated that GE was a better restoration practice than GA in respective of soil N dynamics.

Recovery through proper grazing exclusion promotes the carbon cycle and increases carbon sequestration in semiarid steppe

Grazing exclusion changes soil physical-chemical characteristics, rapidly affects microbial community composition and function, and alters biogeochemical processes, e.g., carbon (C) cycle, over time. However, the temporal dynamics of CO2 emission and CH4 uptake during grassland restoration chronosequences remain poorly understood. We investigated soil CO2 emission and CH4 uptake, the genes related to CO2 and CH4 production and reduction (cbbL, cbbM, chiA, and pmoA), and associated microbial communities under different durations of grazing exclusion (0, 7, 16, 25, and 38 years) to reveal the mechanisms and potential of soil CO2 emission and CH4 uptake in a semi-arid steppe. The results showed that a proper exclusion period could significantly improve soil physical-chemical conditions, vegetation community, and soil C-cycling. The abundance of C-cycling functional genes (cbbL, cbbM, chiA and pmoA), CH4 uptake and CO2 emission rates showed a single-peak pattern with increasing duration of grazing exclusion, peaking at 16 years and then decreasing in the period between 25 and 38 years, indicating that the effect of exclusion weakened when the exclusion period was too long. The changes in C-cycling functional genes and microbial communities are primarily influenced by aboveground net primary productivity (ANPP), and are associated with CO2, CH4, soil water content (SWC), and soil organic carbon (SOC). Structural equation modeling showed that increases in SOC content and pmoA abundance caused by an increase in ANPP accelerated CO2 emission and CH4 uptake rates, respectively. Our results provide valuable insights into the critical role of grazing exclusion in promoting grassland restoration and carbon sequestration, and have potential implications for sustainable land management practices.

Long-Term Grazing Exclusion Increases Ecosystem Carbon Stock but Decreases Nitrogen Stock in the Karst Alpine Grassland of China

Grazing management practices are a major factor regulating nutrient cycling and plant growth in grasslands. However, the response of long-term grazing regimes to ecosystem carbon and nitrogen accumulation and plant productivity remains uncertain in karst landscapes. The purpose of this research is to assess the effects of long-term management measures on plant biomass and ecosystem organic carbon (EOCS), total nitrogen (ETNS), and phosphorus (ETPS) stocks in a karst alpine grassland. A 17 year-long field experiment, constituting the methods of grazing exclusion (GE), continuous grazing (CG), mowing and grazing (MG), and rotational grazing (RG) was established in 2001. Plant and soil samples were collected in 2017. Grazing treatments significantly reduced the aboveground and root biomass (MG and RG) compared to GE. SOC of GE was higher than that of CG, MG, and RG in each soil layer. Grazing promoted the mean TN content with a significant increase in CG and RG. GE significantly increased the EOCS and decreased the ETNS and ETPS. The EOCS increased by 22.29% (MG) and 16.31% (RG) and ETNS increased by 7.76% (RG), and MG significantly decreased ETNS compared to CG. EOCS were positively related to SOC, stoichiometry, and aboveground biomass, while being negatively correlated with TP; ETNS were positively related to TN and TP, while being negatively correlated with C/N, C/P, aboveground biomass, and root biomass; ETPS were positively correlated with TN and TP and negatively correlated with NH4+-N and stoichiometry. GE can provide significant improvements in plant recovery and ecosystem carbon stock, whereas RG is beneficial for promoting ecosystem nutrient stock under the condition of pasturing utilisation in the karst grasslands.

Pollen limitation and context‐dependent alleviating mechanisms in a co‐flowering alpine grassland community

The consequences of community metrics (e.g. co‐flowering diversity and floral density) and plant traits (e.g. pollinator dependency and trait similarity) on pollen limitation (PL) may depend on pollinator‐mediated competitive or facilitative interactions among plants in co‐flowering communities, which could vary with community contexts (i.e. different altitude communities) and under human disturbances (e.g. livestock grazing). However, the mechanisms to alleviate PL under different contexts, considering pollinator‐mediated interactions among neighboring plants are unclear. We investigated PL under grazing versus ungrazing conditions in low versus high altitude alpine meadows on the Tibetan Plateau to uncover the underlying mechanisms mediating PL associated with livestock grazing. We found that PL is prevalent in alpine grasslands, irrespective of community contexts. Grazing exclusion decreased PL in the two sites but in different ways. At the high‐altitude site, PL was reduced by the exclusion of grazers through increased trait similarity (suggesting facilitation). While PL was reduced by decreased trait similarity (suggesting competition avoidance) under grazing exclusion at the low‐altitude site. Our results provide a mechanistic understanding of PL in co‐flowering alpine grassland communities under distinct human disturbances at different altitudes, emphasizing the role of pollinator‐mediated interactions among plants on plant reproductive success.

Grazing exclusion facilitates more rapid ecosystem carbon sequestration of degraded grasslands in humid than in arid regions

Grazing exclusion has been proposed as an effective practice to enhance ecosystem carbon stocks in arid-semiarid degraded grasslands. However, in humid regions, the effects of grazing exclusion on ecosystem carbon stocks and their components in degraded grasslands remain largely unknown. Here, the effects of enclosure on ecosystem carbon stocks and their components were explored using four enclosure ages, each paired with adjacent grazed areas. Moreover, the results were synthesized with previous studies to test if enclosure's effects in semihumid-humid regions differed from those in arid-semiarid regions. The field experiment found that six months to 1 year of grazing exclusion sequestrated 14.6 % higher carbon in the enclosed grasslands than in paired-grazed grasslands as a consequence of increased carbon storage of plants and topsoils. However, compared to grazed areas, enclosures over 3–6 years contained 14.4 % less ecosystem carbon stocks, primarily due to markedly decreased soil carbon sequestration, despite increased plant carbon stocks. Structural equation models further suggested that the decrease in soil carbon stock might be owing to the decomposition of organic matter induced by low phosphorus. Additionally, compared with the northern slope of the mountain, ecosystem carbon stocks on the southern slope showed a lagged and weak response to grazing exclusion. The results, combined with a meta-analysis, revealed that plant and soil carbon stocks in semihumid-humid grasslands were more sensitive to enclosure than in arid-semiarid grasslands. These results highlight that short-term fencing (e.g., six months to 1 year), rather than long-term, is a practical strategy to foster degraded grassland ecosystem carbon sequestration in semihumid-humid regions, thus contributing to climate change mitigation.

Changes in vegetation structure and hydrological function in response to rangeland rest

An experiment was carried out to evaluate the effects of grazing rest on the vegetation structure, the hydrological function, and the ecological status in grasslands of regular condition for cattle. The study area is located at 4,095 meters above sea level, in the Cordillera Blanca peasant community, Ancash Region, Peru. The experimental design was factorial 2 x 2 in blocks, where the factors were: a) two grazing systems P1: uncontrolled grazing on communal usufruct lands and P2: rest or total exclusion of grazing, and b) three years of monitoring from 2011 to 2013. At the end of the study, the vegetation structure changed according to the regime of the rangeland use, where rest favored the increase of local gramineae species, but unfavorable for herbs, pseudogramineae, and shrubs. Resting increased the vegetation cover, the accumulation of biomass and mulch on the ground with respect to grazing (P < 0.01). The hydrological function improved with the application of rest compared to grazing, which was reflected in a higher infiltration capacity and soil moisture content (P < 0.01). The ecological processes improved with resting compared to grazing expressed by the increase of the ecological status of the pasture, in response to the improvement of the components that determine its value, such as forage species and vigor (P < 0.01).

Transient shifts in composition of degraded temperate native grassland following grazing exclusion

AbstractQuestionsGlobally, grassy ecosystems are threatened and are still declining in extent in many areas. Improving the management of degraded native temperate grasslands that are grazed by livestock is important to the conservation of this critically endangered ecosystem. Questions remain about the role of grazing in the management of such grasslands, particularly in the face of climate change and given the sensitivity of these systems to inter‐annual rainfall variability. Here, we investigate the effect of livestock exclusion on grassland composition.LocationTemperate grassland, Victoria, Australia.MethodsOver 9 years (2009–2017), we monitored plant functional groups in plots open‐to‐grazing or ungrazed exclusion plots within five fields of degraded native temperate grassland on private land.ResultsIn the years after grazing had been excluded, we found significant differences in cover between grazed and ungrazed plots for some functional groups (e.g. native perennial graminoids) in some years, but we did not observe long‐term divergence in cover or composition of the treatments. At the final monitoring point there were no significant differences in native or exotic species richness between the grazed and ungrazed plots. We show that the years in which differences were observed correspond with the 2010–2011 La Niña high‐rainfall event, suggesting that grazing exclusion effects are mediated by rainfall, and are likely to be evident only under certain conditions.ConclusionIn grassy ecosystems already degraded by long‐term grazing, excluding grazing has limited potential to shift plant species composition in favour of native dominance. Such grasslands may persist in the medium term in a stable but degraded state with or without continued light to moderate livestock grazing pressure. Hence, managed livestock grazing need not be incompatible with the conservation of degraded temperate grasslands particularly where biomass management is important for the maintenance of faunal habitat. However, improving the function and diversity of these degraded grasslands will seemingly require additional management, including seed addition and experimentation with alternative disturbance regimes.

Effects of Grazing Exclusion on Vegetation and Soil Properties of a Leymus chinensis Steppe in China

Effects of Grazing Exclusion on Vegetation and Soil Properties of a Leymus chinensis Steppe in China

Optimized soil bacterial structure following grazing exclusion promotes soil nutrient cycling and plant growth

Grazing exclusion is a common grassland restoration strategy, and the effectiveness on optimizing plant species community, increasing vegetation diversity and biomass, and improving soil fertility, has been widely documented in literatures. Soil bacterial community, as one of important ecological components, closely relates to plants and soil features. However, there is no definite conclusion of grazing exclusion effects on various ecological components, especially on soil bacterial community. To clarify this question, we compared the soil bacterial community characteristics and their corresponding vegetation characteristics and soil properties on one 40 years-grazing exclusion (GE) and three free grazing (FG) areas within a Leymus chinensis steppe of Inner Mongolia, China. Our results showed that grazing exclusion could significantly increase the soil bacterial abundance, and optimize the soil bacterial structure, with the synergistic increase of the soil bacterial diversity. The abundance of Euryarchaeota, Verrucomicrobia, Nitrospirae, Proteobacteria, Elusimicrobia, Latescibacteria, and Microgenomates phyla, some taxa of which involved in the N and P cycles, increased significantly following grazing exclusion, while the abundance of Chloroflexi, Firmicutes, Thaumarchaeota, and Pacearchaeota phyla which are often considered to contain many pathogens, decreased significantly. The bacterial phyla increased by grazing exclusion have a significant positive correlation with vegetation biomass and diversity, and soil alkali-hydrolyzable nitrogen content, total nitrogen content, total phosphorus content, organic matter content and water content. The reducing of pathogenic abundance after grazing exclusion provides a healthier environment for plant growth. This work indicates that grazing exclusion optimizes the soil bacterial structure to promote the growth of plants in more sufficient soil nutrients and healthier soil environments, making the enclosed grassland soil ecology form a virtuous circle.

Does grazing exclusion enhance grassland restoration? evidence from northern China

Grazing exclusion programs have been widely implemented worldwide for decades to address the negative impacts of overgrazing and promote grassland restoration. Nevertheless, there is still a lack of understanding of the causal links between grazing exclusion and grassland restoration. To explore these interactions in greater detail, we examined a large-scale georeferenced dataset focusing on a grazing exclusion program implemented in North China. The main analysis in the study showed that grazing exclusion significantly increased grassland area while having no significant effect on the improvement in grassland quality, measured by average net primary productivity (ANPP) and Normalized Difference Vegetation Index (NDVI). Our analysis also showed the heterogeneous effect of grazing exclusion on grassland restoration in regions with varying initial grassland conditions and levels of local economic development. In particular, our study suggests that grazing exclusion should first be promoted in regions with high levels of income, and we suggest to pay more attention to newly restored grassland and select proper post-restoration management. Finally, we provide new evidence of the importance of moderately increasing ecological compensation.

Maintaining scattered trees to boost carbon stock in temperate pastures does not compromise overall pasture quality for the livestock

Scattered trees in wood-pastures represent outstanding conservation value by providing microhabitats for a variety of organisms. They also diversify ecosystem services by creating shade for livestock, and capturing and storing carbon. However, trees in wood-pastures are declining Europe-wide and an appropriate legal environment to maintain them is mostly lacking. Here we looked beyond the well-documented beneficial effects of trees and assessed potential ecosystem disservices, which may drive the controversial appreciation of trees. In a grazing exclusion experiment, we assessed the effect of trees on herbage production in wood-pastures from semi-arid continental to humid montane areas in the temperate deciduous forest ecoregion, and found that trees have a suppressive effect throughout the year, although herbage nutritive value, as indicated by herbage nitrogen content, seems to be improved in spring. When we up-scaled the local ecosystem disservice on herbage yield to entire wood-pastures, the loss remained below 3%, which is lower than reported gains in livestock production due to free access to shade. Thus, the motivation for the under-appreciation of trees by land managers and decision makers may lie in that trees suppress herbage production, but the importance of this effects is offset by the magnitude of the beneficial services of trees. We recommend current wood-pasture stakeholders to revisit their attitude towards scattered trees and encourage tree planting campaigns and tree-based climate mitigation strategies to consider the protection of trees in wood-pastures and the establishment of young ones in currently open pastures up to traditionally low tree cover proportions, as livestock production is unlikely to be compromised by this action.