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Climate change is increasing the frequency and severity of short-term (~1 y) drought events-the most common duration of drought-globally. Yet the impact of this intensification of drought on ecosystem functioning remains poorly resolved. This is due in part to the widely disparate approaches ecologists have employed to study drought, variation in the severity and duration of drought studied, and differences among ecosystems in vegetation, edaphic and climatic attributes that can mediate drought impacts. To overcome these problems and better identify the factors that modulate drought responses, we used a coordinated distributed experiment to quantify the impact of short-term drought on grassland and shrubland ecosystems. With a standardized approach, we imposed ~a single year of drought at 100 sites on six continents. Here we show that loss of a foundational ecosystem function-aboveground net primary production (ANPP)-was 60% greater at sites that experienced statistically extreme drought (1-in-100-y event) vs. those sites where drought was nominal (historically more common) in magnitude (35% vs. 21%, respectively). This reduction in a key carbon cycle process with a single year of extreme drought greatly exceeds previously reported losses for grasslands and shrublands. Our global experiment also revealed high variability in drought response but that relative reductions in ANPP were greater in drier ecosystems and those with fewer plant species. Overall, our results demonstrate with unprecedented rigor that the global impacts of projected increases in drought severity have been significantly underestimated and that drier and less diverse sites are likely to be most vulnerable to extreme drought.

Soil microbial communities perform critical ecosystem services through the collective metabolic activities of numerous individual organisms. Most microbes use corrinoids, a structurally diverse family of cofactors related to vitamin B12. Corrinoid structure influences the growth of individual microbes, yet how these growth responses scale to the community level remains unknown. Analysis of metagenome-assembled genomes suggests that corrinoids are supplied to the community by members of the archaeal and bacterial phyla Thermoproteota, Actinobacteria, and Proteobacteria. Corrinoids were found largely adhered to the soil matrix in a grassland soil, at levels exceeding those required by cultured bacteria. Enrichment cultures and soil microcosms seeded with different corrinoids showed distinct shifts in bacterial community composition, supporting the hypothesis that corrinoid structure can shape communities. Environmental context influenced both community- and taxon-specific responses to specific corrinoids. These results implicate corrinoids as key determinants of soil microbiome structure and suggest that environmental micronutrient reservoirs promote community stability.

Global warming modulates soil respiration (RS) via microbial decomposition, which is seasonally dependent. Yet, the magnitude and direction of this modulation remain unclear, partly owing to the lack of knowledge on how microorganisms respond to seasonal changes. Here, we investigated the temporal dynamics of soil microbial communities over 12 consecutive months under experimental warming in a tallgrass prairie ecosystem. The interplay between warming and time altered (P

The long-standing assumption that aboveground plant litter inputs have a substantial influence on soil organic carbon storage (SOC) and dynamics has been challenged by a new paradigm for SOC formation and persistence. We tested the importance of plant litter chemistry on SOC storage, distribution, composition, and age by comparing two highly contrasting ecosystems: an old-growth coast redwood (Sequoia sempervirens) forest, with highly aromatic litter, and an adjacent coastal prairie, with more easily decomposed litter. We hypothesized that if plant litter chemistry was the primary driver, redwood would store more and older SOC that was less microbially processed than prairie. Total soil carbon stocks to 110 cm depth were higher in prairie (35 kg C m-2) than redwood (28 kg C m-2). Radiocarbon values indicated shorter SOC residence times in redwood than prairie throughout the profile. Higher amounts of pyrogenic carbon and a higher degree of microbial processing of SOC appear to be instrumental for soil carbon storage and persistence in prairie, while differences in fine-root carbon inputs likely contribute to younger SOC in redwood. We conclude that at these sites fire residues, root inputs, and soil properties influence soil carbon dynamics to a greater degree than the properties of aboveground litter.

Estimating the latent heat flux (λET) accurately is important for water-saving irrigation in arid regions of Northwest China. The Penman-Monteith model is a commonly used method for estimating λET, but the parameterization of canopy resistance in the model has been a difficulty in research. In this study, continuous observation of λET during the growing period of maize and grassland in Northwest China was conducted based on the Bowen ratio energy balance (BREB) method and the Eddy covariance system (ECS). Two methods, Katerji-Perrier (K-P) and Garcıá-Santos (G-A), were used to determine the canopy resistance in the Penman-Monteith model and the estimation errors and causes of the two sub-models were explored. The results indicated that both models underestimated the λET of grassland and maize. The K-P model performed relatively well (R² > 0.94), with the root mean square errors (RMSE) equaled 37.3 and 28.1 W/m² for grass and maize, respectively. The accuracy of the G-A model was slightly lower than that of the K-P model, with the determination coefficient (R²) equaled 0.90 and 0.92, and the RMSE equaled 46.2 W/m² (grass) and 42.1 W/m² (maize). The vapor pressure deficit (VPD) was the main factor affecting the accuracy of K-P and G-A sub-models. The error of two models increased with the increasing in VPD for both crops. [ABSTRACT FROM AUTHOR]

Coprophilous fungal spores are an emerging and potential proxies for indicating the long-term pastoral history. However, the indication of coprophilous fungal spores for dung and grazing intensity remains uncertain. In this study, in Horqin Sandy Land, 27 livestock dung samples and 33 surface soil samples were collected, and the indication of coprophilous fungal spores was discussed for the first time. The results showed that a total of 38 fungal spore types were recognized in the modern samples from the Horqin Sandy Land, including seven coprophilous fungal spore types. The coprophilous fungi assemblages vary in different dung types and may enable the diagnosis of specific livestock taxa. Coprophilous fungal spores, especially Sporormiella and Podospora are the most reliable dung indicators and can indicate the presence of herbivores. Moreover, some fungal spores, including Helminthosporium, Apiosordaria, HdV-104, and Glomus A were also potential indicators of grazing activities in the Horqin Sandy Land. On this basis, the concentration of coprophilous fungal spores may have the potential to be a quantitative indicator of grazing intensity. This study clarifies the indication of coprophilous fungal spores on dung and grazing intensity in the Horqin Sandy Land and provides a theoretical reference for further research on pastoral history in the region. [ABSTRACT FROM AUTHOR]

The study of the polarimetric target decomposition algorithm with physical scattering models has contributed to the development of the field of remote sensing because of its simple and clear physical meaning with a small computational effort. However, most of the volume scattering models in these algorithms are for forests or crops, and there is a lack of volume scattering models for grasslands. In order to improve the accuracy of the polarimetric target decomposition algorithm adapted to grassland data, in this paper, a novel volume scattering model is derived considering the characteristics of real grassland plant structure and combined with the backward scattering coefficients of grass, which is abstracted as a rotatable ellipsoid of variable shape. In the process of rotation, the possibility of rotation is considered in two dimensions, the tilt angle and canting angle; for particle shape, the anisotropy degree A is directly introduced as a parameter to describe and expand the applicability of the model at the same time. After obtaining the analytical solution of the parameters and using the principle of least negative power to determine the optimal solution of the model, the algorithm is validated by applying it to the C-band AirBorne dataset of Hunshandak grassland in Inner Mongolia and the X-band Cosmos-Skymed dataset of Xiwuqi grassland in Inner Mongolia. The performance of the algorithm with five polarimetric target decomposition algorithms is studied comparatively. The experimental results show that the algorithm proposed in this paper outperforms the other algorithms in terms of grassland decomposition accuracy on different bands of data. [ABSTRACT FROM AUTHOR]

A major factor hindering ecological restoration is uncertainty about which plant species will best establish. We account for this uncertainty in the design of seed mixes, though our developments are relevant to other planting mixes (e.g. root stock). We view seed mixes as being comprised of one or more species groups (e.g. shrubs, grasses, and nitrogen fixers). We mathematically establish that chances of relatively low densities decline as a species group's seeding rate (e.g. 100 seeds/m2) is divided more evenly among more species. This decline is sharpest if survival probabilities vary widely among species. To determine how much survival probabilities typically vary, we studied grasses commonly seeded in Great Plains grasslands and Mediterranean annual grasslands in the western United States. Survival probabilities varied extensively, so the chances of low densities declined markedly with increasing seeded species numbers. In the Great Plains, the chances of establishment failures (0 plants/m2) were 50% when the seeding rate was allocated to one species versus 0% when the seeding rate was divided evenly among five or more species. Similarly, in Mediterranean annual grasslands, the chances of very low densities (≤1.0 plants/m2) declined from 24% when one species was seeded to 0% when three or more species were seeded. The seeding rate for each plant group should be divided as evenly as possible among as many species as practical. Compared to increasing seeding rates to provide greater densities, dividing fixed rates more evenly among more species could prove less expensive. [ABSTRACT FROM AUTHOR]

Ungulate herbivores shape grassland plant communities at multiple scales, ultimately affecting ecosystem function. However, ungulates have complex effects on grasslands, including defoliation, trampling, excreta return and their interactions. Moreover, the effects of ungulate density on grasslands are regulated by these three mechanisms. Nevertheless, how these three mechanisms affect biodiversity at multiple scales and community assembly remains poorly understood. Here, we conducted a 4‐year novel field experiment to disentangle the effects of defoliation, trampling, and excreta return by ungulates on plant community assembly in a temperate grassland in Inner Mongolia, China. This experiment set two different scenarios: moderate ungulate density (Moderate, characterised by selective defoliation and moderate trampling) and high ungulate density (Intense, characterised by non‐selective defoliation and heavy trampling), including different combinations of defoliation, trampling and excreta return in each scenario. We found that defoliation and trampling increased stochasticity in community assembly and promoted alpha and beta diversity under both scenarios. Specifically, defoliation promoted the coexistence of species with multiple resource acquisition strategies (higher functional trait diversity) by reducing interspecific competition; trampling tended to facilitate random species colonisation. Conversely, excreta return favoured grasses, promoting deterministic assembly and impacting species coexistence. Notably, selective defoliation in the Moderate scenario led to a dominance of stochastic processes during community assembly, whereas non‐selective defoliation still did not change the dominance of deterministic processes. Further, communities subject to selective defoliation were insensitive to changes in soil properties caused by trampling and excreta return, maintaining a high‐level beta diversity and the stochastic of community assembly. Synthesis: Our study provides important insights into the mechanisms by which ungulate herbivores influence plant community assembly, suggesting that defoliation and trampling have the potential to drive stochastic processes, while excreta return plays the opposite role. Our study also suggests that selective foraging by ungulates acts as stronger stochastic forces during community assembly compared to non‐selective defoliation. These results imply that considering ungulate feeding preferences and foraging behaviour in grassland management will help prevent biodiversity loss and biotic homogenisation. [ABSTRACT FROM AUTHOR]

In organic farming, clover is an important basis for green manure in crop rotation systems due to its nitrogen-fixing effect. However, clover is often sown in mixtures with grass to achieve a yield-increasing effect. In order to determine the quantity and distribution of clover and its influence on the subsequent crops, clover plants must be identified at the individual plant level and spatially differentiated from grass plants. In practice, this is usually done by visual estimation or extensive field sampling. High-resolution unmanned aerial vehicles (UAVs) offer a more efficient alternative. In the present study, clover and grass plants were classified based on spectral information from high-resolution UAV multispectral images and texture features using a random forest classifier. Three different timestamps were observed in order to depict the phenological development of clover and grass distributions. To reduce data redundancy and processing time, relevant texture features were selected based on a wrapper analysis and combined with the original bands. Including these texture features, a significant improvement in classification accuracy of up to 8% was achieved compared to a classification based on the original bands only. Depending on the phenological stage observed, this resulted in overall accuracies between 86% and 91%. Subsequently, high-resolution UAV imagery data allow for precise management recommendations for precision agriculture with site-specific fertilization measures. [ABSTRACT FROM AUTHOR]

This study modelled the drivers of satellite-derived Net Primary Productivity (NPP). The NPP drivers used were human foot print (HFP), soil organic carbon (SOC), Total Nitrogen (TN), Total Phosphorus (TP), Potential evapotranspiration, (PET), and Aridity Index (AI). The results showed that inclusion of non-vegetated land cover types (LCT) in the modelling leads to establishment of wrong relationships between the NPP and its drivers, and wrong relationships among the drivers. Inclusion of the non-vegetated LCT revealed that 1) HFP had no relationship with NPP, CUE, and SOC; 2) PET had no relationship with all the three soil variables (SOC, TN, and TP), AI and the CUE; 3) PET and NPP were strongly and positively correlated; and 4) there was no relationship between the NPP and all the three soil variables and the AI. While exclusion of the non-vegetated LCT revealed that 1) HFP had negative relationship with NPP, CUE, and SOC; 2) PET had negative relationship with the CUE, AI and all the three soil variables; 3) PET and NPP were strongly negatively correlated; and 4) there was positive correlations between the NPP and all the three soil variables and AI. However, results of both the inclusion and exclusion of the non-vegetated LCT indicated that: 1) HFP did not correlate with TN, TP, PET, and AI; and 2) there was strong and positive correlation among all the three soils and AI. It is worth noting that exclusion of the non-vegetated LCT in the modelling established the most accurate results on the relationship between the NPP and its drivers; and on the relationships among the drivers. However, there is a need to replicate this study in different geographical regions to guarantee global generalization of the results. [ABSTRACT FROM AUTHOR]

In Central Europe, Taraxacum officinale Weber ex Wiggers (dandelion) is an economically important admixture in grasslands. Its spread is supported by its ability to germinate in gaps in grass stands. In a 5‐year experiment, we examined the effect of gap size on the germination rate and percentage of dandelion achenes. Each year, achenes were sown in late spring and mid‐summer in 90 square plots of six sizes, ranging from 2.5 × 2.5 cm to 80 × 80 cm. The plots were placed on a 2 × 6 m experimental area covered with low‐cut lawn. The course of germination varied among individual replicates depending on the weather. In each replicate, however, the rate of germination increased, and the percentage of germinated achenes decreased with increasing gap size. Differences in germination paralleled differences in the microclimate on the soil surface of plots where humidity decreased and temperature increased with plot size. The ultimate cause of this difference was the variance among gaps of different sizes in proportion to which the total area of the gap surface is insolated during the day. The colonization of lawns by dandelion is supported by the formation of small gaps in grass stands. [ABSTRACT FROM AUTHOR]

Agricultural grasslands play an important role in conserving the biodiversity of the European cultural landscape. Both, litter cover and soil nutrient availability, change with grassland management, but it is not well‐studied how seedling recruitment and growth of multiple grassland species are influenced by their single or combined effects. Therefore, we studied the effects of nitrogen fertilization (100 kg N per year and ha) and litter cover (250 gdw per m2) on seedling recruitment and growth of 75 temperate grassland species (16 graminoid species, 51 forb species, 8 legume species) in a full factorial microcosm experiment. Overall, fertilizer reduced seedling emergence, while litter cover increased it even when combined with fertilization. Fertilization increased seedling height and biomass, and the combination of fertilizer and litter resulted in even stronger responses. Litter cover alone did not influence seedling biomass or seedling height. While the overall direction of treatment effects was similar across functional groups, their strengths were mostly weaker in graminoids than in non‐legume forbs and legumes. Positive litter effects on seedling emergence were stronger in large‐seeded species. Positive fertilization effects on seedling growth were stronger in small‐seeded species, while their seedling biomass was negatively affected by litter cover. In summary, our results show for multiple grassland species that the combination of litter cover and fertilization modulates their single effects. The varying sensitivity of how grassland species representing different functional groups and seed sizes respond with their seedling emergence and growth to litter cover and nitrogen fertilization indicates that the consequences of land‐use change on grassland diversity and composition already start to manifest in the earliest stages of the plant life cycle. [ABSTRACT FROM AUTHOR]

Soils are a valuable renewable resource on human timescales, and they interact with distinctive grassland ecosystems characterized by unique biodiversity and essential provision of ecosystem services, such as water supply and carbon sequestration. However, knowledge of the effects of wildfires on soil properties and nutrient availability in the Andes remains limited. Andean grasslands are currently one of the ecosystems of the Peruvian Andes most affected by wildfires. Our objective is to analyze the effect of fire activity on the physicochemical properties of soil and analyze its social context in Cusco, in the southern Andes of Peru. Soil samples were collected during five periods, spanning both the dry and rainy seasons, to characterize changes in soil properties and monitor vegetation recovery post-fire in two local communities dedicated to livestock activities. The vegetation restored after the wildfire was measured by the "step transect" method. Post-fire changes in soil properties indicate slight increases in pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium during the onset of the rainy season; thereafter, a gradual reduction in these values was observed. This reduction can be attributed to leaching associated with the seasonal rainfall and runoff regime. Our findings indicate that one-year post-fire, the biomass in burned areas is reduced to 30–46% of the biomass in unburned areas. A complete regeneration is likely to occur in up to 4 years; this assertion is supported by the perceptions of the affected population, as expressed in interviews conducted in the two farming communities. These results are significant for decision-makers formulation of policies and regulations regarding grasslands and their seasonal restoration. [ABSTRACT FROM AUTHOR]

Plant growth and food security depend heavily on phosphorus (P). Recovering and recycling P from animal, municipal, and food waste streams can significantly reduce dependency on traditional mineral P. This is particularly pertinent in the EU regions with limited native P supplies. The agronomic performance of including P-based recycling-derived fertilisers (two struvite and two ashes) or cattle slurry was compared to a conventional mineral P fertilisation programme along with no P and no fertiliser controls over three years. A field-scale experiment was set up to evaluate the perennial ryegrass dry matter yield (DMY), P uptake, and soil test P effects. Struvite, ash, and cattle slurry proved effective in replacing P mineral fertiliser and produced yields similar to those of the mineral fertiliser programme. Differences were observed in plant P recovery, with struvite-based programmes achieving a significantly higher P recovery than ash-based programmes, which had the lowest plant P recovery. Differences in Morgan's soil test P were also noted, with potato waste struvite (PWS) and poultry litter ash (PLA) showing significantly higher soil test P values. The findings strongly indicate that a range of recycled bio-based fertilisers from the bioeconomy can be used to reduce reliance on conventional imported mineral P fertiliser, with some programmes based on recycled fertilisers even surpassing the performance of conventional linear economy mineral fertilisers. [ABSTRACT FROM AUTHOR]

Phosphorus is one of the major constraints to karst grassland productivity. Understanding the effects of different fertilization practices on soil phosphorus dynamics is essential for enhancing phosphorus bioavailability and rational management of soil phosphorus in karst grasslands. Here, we investigated the effects of fertilizers and manures on soil bioavailability of phosphorus fractions and explored the relationship between soil properties and soil phosphorus fractions. The four fertilizer application designs were as follows: control (CK; no fertilizer or manure); fertilization (F); manure application (M); fertilization and manure application (FM). The results showed that total phosphorus (TP) concentration was elevated by 23%, 1%, and 42% in F, M, and FM treatments, respectively, compared with CK. F and FM treatments enhanced the total inorganic phosphorus (Pi) concentration by 65% and 66%, respectively, while M and FM treatments enhanced the total organo-phosphorus (Po) concentration by 21% and 35%, respectively. FM treatment elevated bioavailable P, active Po, secondary mineral P, primary mineral P, and occluded P by 69%, 39%, 50%, 31%, and 41%, respectively. Fertilizers inhibited soil acid phosphatase activity, whereas alkaline phosphatase did not respond significantly to fertilizer management in low-latitude karst regions. SOM, TN, AP, and MBP are the key factors affecting the bioavailability of phosphorus fractions. The combined application of fertilizer and manure is the most beneficial measure for enhancing soil phosphorus bioavailability. This research helps deepen our understanding of soil phosphorus dynamics in the karst areas and provides a basis for further enhancement of nutrient availability and vegetation productivity of grassland ecosystems. [ABSTRACT FROM AUTHOR]

The fraction of net primary productivity (NPP) allocated to belowground organs (fBNPP) in grasslands is a critical parameter in global carbon cycle models; moreover, understanding the effect of precipitation changes on this parameter is vital to accurately estimating carbon sequestration in grassland ecosystems. However, how fBNPP responds to temporal precipitation changes along a gradient from extreme drought to extreme wetness, remains unclear, mainly due to the lack of long‐term data of belowground net primary productivity (BNPP) and the fact that most precipitation experiments did not have a gradient from extreme drought to extreme wetness. Here, by conducting both a precipitation gradient experiment (100–500 mm) and a long‐term observational study (34 years) in the Inner Mongolia grassland, we showed that fBNPP decreased linearly along the precipitation gradient from extreme drought to extreme wetness due to stronger responses in aboveground NPP to drought and wet conditions than those of BNPP. Our further meta‐analysis in grasslands worldwide also indicated that fBNPP increased when precipitation decreased, and the vice versa. Such a consistent pattern of fBNPP response suggests that plants increase the belowground allocation with decreasing precipitation, while increase the aboveground allocation with increasing precipitation. Thus, the linearly decreasing response pattern in fBNPP should be incorporated into models that forecast carbon sequestration in grassland ecosystems; failure to do so will lead to underestimation of the carbon stock in drought years and overestimation of the carbon stock in wet years in grasslands. [ABSTRACT FROM AUTHOR]

Plant enemies can influence plant community assembly and structure. However, it is unclear how insect herbivores and fungal pathogens affect seedling recruitment. Complex interactions with competition and resource availability make it difficult to isolate the effect of enemies. This uncertainty can impede understanding of community assembly drivers, species coexistence and trophic interactions; and limits hypothesis testing such as of the enemy release hypothesis, a key hypothesis in invasion biology. Using a novel species‐specific approach, we examine how enemies affect seedling survival and recruitment of 16 grassland species.We planted seedlings of 16 native species from two functional groups (C4 grasses and non‐legume forbs) into two grassland sites (early and mid‐succession). We hand‐painted 1512 individual seedlings with pesticides (insecticide and fungicide) over the course of one growing season to enforce aboveground species‐specific release from enemies and tested whether it enhanced survival relative to untreated controls. Applying treatments to individuals allowed us to test for the effect of enemies on plant performance while controlling for contexts such as competition from the resident community and resource levels.Release from insects increased seedling survival by 56% on average, with no additional benefit of release from fungal pathogens. This effect was observed for both forbs and C4 grasses across both sites and was strongest in resource‐acquisitive species. There was no effect of the mean phylogenetic distance between our target species and the resident plant community, or of light availability or soil moisture.Synthesis. The significant positive effect of release from insect herbivores on survival early in colonisation—a trend that held across functional groups and types of resident community—suggests insects play an important regulatory role in community assembly, especially for resource‐acquisitive species. As variation between species could be explained by traits but not by phylogeny, we emphasise the importance of trait‐based approaches to plant community ecology. Our results also support the key mechanism (increased performance following release from enemies) underlying the enemy release hypothesis. Enemy release may therefore aid initial recruitment of plants during the invasion process. [ABSTRACT FROM AUTHOR]

Root production influences carbon and nutrient cycles and subsidizes soil biodiversity. However, the long‐term dynamics and drivers of belowground production are poorly understood for most ecosystems. In drylands, fire, eutrophication, and precipitation regimes could affect not only root production but also how roots track interannual variability in climate.We manipulated the intra‐annual precipitation regime, soil nitrogen, and fire in four common Chihuahuan Desert ecosystem types (three grasslands and one shrubland) in New Mexico, USA, where the 100‐year record indicates both long‐term drying and increasing interannual variability in aridity. First, we evaluated how root production tracked aridity over 10–17 years using climate sensitivity functions, which quantify long‐term, nonlinear relationships between biological processes and climate. Next, we determined the degree to which perturbations by fire, nitrogen addition or intra‐annual rainfall altered the sensitivity of root production to both mean and interannual variability in aridity.All ecosystems had nonlinear climate sensitivities that predicted declines in production with increases in the interannual variance of aridity. However, root production was the most sensitive to aridity in Chihuahuan Desert shrubland, with reduced production under drier and more variable aridity.Among the perturbations, only fire altered the sensitivity of root production to aridity. Root production was more than twice as sensitive to declines with aridity following prescribed fire than in unburned conditions. Neither the intra‐annual seasonal rainfall regime nor chronic nitrogen fertilization altered the sensitivity of roots to aridity.Synthesis. Our results yield new insight into how dryland plant roots respond to climate change. Our comparison of dryland ecosystems of the northern Chihuahuan Desert predicted that root production in shrublands would be more sensitive to future climates that are drier and more variable than root production in dry grasslands. Field manipulations revealed that fire could amplify the climate sensitivity of dry grassland root production, but in contrast, the climate sensitivity of root production was largely resistant to changes in the seasonal rainfall regime or increased soil fertilization. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the effects of grazing and non-grazing on the physicochemical properties, stoichiometry, ecto-enzyme activities, and microbial element limitations of soils at five depths in subtropical grassland, China, and to identify the influencing factors of enzyme activities and element limitations. Results showed that grazing, soil depth, and the interaction between grazing and depth remarkably changed soil available phosphorus (AP), available potassium (AK), available calcium (ACa) and available magnesium contents (AMg), bulk density (BD), water content (WC), and β-glucosidase activity (βGC) (p = 6.702e-9 - 0.04739). Compared with no g razing, g razing remarkably declined the 0-5 cm soil AP by 73.10% (p = 0.0250), the 0-5, 5-10, 10-20 cm soil WC by 47.19% (p = 0 .0042), 3 7.19% ( p = 0 .0090), a nd 3 0.80% ( p = 0.0034), however, grazing remarkably increased the 0-5, 5-10, 10-20, 20-30 cm soil ACa by 188.76% (p = 7.9e-05), 93.24% (p = 0.0177),84.18% (p = 0.00067), and 38.77% (p = 0.01368), the 0-5, 5-10 cm soil AMg by 186.69% ( p = 0.0016), 78.89% (p = 0.0109), t he 0-5, 5-10, 1 0-20 c m s oil pH b y 0 .51 ( p = 0.0013), 0.37 (p = 0.0006), and 0.27 (p = 0.0114) units, the 0 -5, 5-10, 10-20 cm soil BD by 59.03% ( p = 0.0077), 44.14% ( p = 0.0147), and 35.55% (p = 0.0071), the 30-50 cm soil WC by 22.88% (p = 0.0241), the 0-5 cm soil βGC by 89.49% (p = 0.0011), the 0-5, 5-10 cm soil ACP by 7.87% (p = 0.0300), 6.57% (p = 0.0240), respectively. Grazing exacerbated the microbial C limitation of 0-5 and 10-20 cm soils by 20.51% (p = 0.0078) and 40.38% (p = 0.0209) and switched the soil microbiome from under N limitation to under P limitation at 5-10 cm (p = 0.0390). Specific soil available cations were identified as the important factors that significantly explained the variation of soil ecto-enzyme activities and soil microbial carbon and nutrient limitations. These findings present basic information for the future improvement management of subtropical grassland and understanding the impact of grazing on microbial element limitation. [ABSTRACT FROM AUTHOR]

Introduction: Grassland-livestock balance is an important principle of sustainable development of grassland livestock production and grassland ecosystem health. Grassland degradation becomes more serious at global scales and especially at the area that is sensitive to climate change and human activities. Decreases in pasture biomass and shifts in plant community composition in degraded grasslands can largely affect grazing behaviors of livestock. Up to date, however, it is unclear that whether livestock behaviors change across spatial and temporal scales and what key factors are to shape observed behavioral patterns of livestock. Methods: Here, yak behaviors including grazing, rumination and walking on the eastern Qinghai-Tibetan Plateau (QTP) were monitored by a continuous visual observation, to investigate temporal and spatial variations of grazing behavior of yaks (Bos grunniens); based on the data from public database in the past 18 years, a meta-analysis was conducted to examine the main factors that affect grazing behaviors and intake of yaks. Results: We showed that grazing behaviors of yaks differed significantly within hours, among hours of each day and among days as well as across different observation sites. Intake rate of yaks was higher in the morning than in the afternoon, but walking speed showed an inverse trend compared with intake rate. Resting, altitude, the mean annual precipitation (MAP), the mean annual temperature (MAT), forage ash, yak age and season were the main predictors for yak intake, and forage and yak individual characteristics had direct effects on grazing behaviors and intake of yaks. Discussion: The findings confirm that grazing behaviors of yaks can vary even at small temporal scales and regional scales, which is closely related to the shift in forage quality and biomass caused by environmental changes. The study suggests that multiple factors can be responsible for the variation in livestock behaviors and shifts in behavioral patterns may consequently lead to positive or negative feedback to grassland ecosystems through plant-animal interactions. [ABSTRACT FROM AUTHOR]

An increasing number of studies in botanical gardens are investigating species' responses to climate change. However, the influence of local environmental or habitat conditions such as soil nutrient status or microclimate on phenology and the link between morpho‐physiological functional traits and phenological stages are poorly understood, making it difficult to extrapolate patterns from botanical gardens to natural environments. Therefore, we selected herbaceous species growing in two semi‐natural habitats, namely, semi‐dry grasslands (SDGs) and mesophilic grasslands (MGs) and the botanical garden of Jena (Germany) to investigate the influence of habitat conditions on interspecific and intraspecific patterns in phenology, functional traits and their associations. For 16 species, we monitored leaf and flowering phenology weekly for 133 populations from the three habitats, measured morpho‐physiological traits (i.e., whole plant, leaf and reproductive traits), as well as habitat conditions and compared the measurements across habitats. Multivariate analyses revealed that morpho‐physiological traits conspicuously showed stronger differences between habitats compared to phenological traits. Populations on MG showed temporal niche segregation, whereas populations on SDG showed flowering synchrony. Boosted Regression Trees showed that morpho‐physiological traits, especially reproductive traits, strongly influenced phenological traits and that the trait‐phenology relationships were highly habitat‐specific. We conclude that species phenology is broadly similar between botanical gardens and local habitats. However, phenological responses to the environment may be constrained by a certain suite of correlated traits due to ecological plant strategies that vary across habitats. The effect of habitat conditions on morpho‐physiological functional traits and phenology‐trait relationships is important and should not be neglected at local scales, implying consequences at larger scales. [ABSTRACT FROM AUTHOR]

Global climate change is considered one of the greatest environmental threats in the world. It is expected to significantly change the global hydrological cycle. The two main water cycle components, potential evapotranspiration (PET) and precipitation (P), are closely related to vegetation dynamics. In this study, the partial correlation analysis method was used to analyzed the relationship between Normalized Difference Vegetation Index (NDVI) and climate factors (PET and P) based on grid cells. PET was calculated by FAO-56 Penman-Monteith method. Moreover, we also investigated the NDVI and climate factors in different vegetation cover types. The results showed that grassland, forest and cropland in China were positively correlated with PET and P. The time scales of the maximum partial correlation coefficients between NDVI and PET of grassland vegetation were mostly longer than 5-6 months. These time scales were longer than the time scales related to P. The partial correlation coefficients between NDVI and PET, P of forest vegetation were higher in northern China, whereas the spatial distribution of related time scales was the opposite. The partial correlation coefficients between NDVI and PET, P of forest vegetation were higher in northern China. However, the spatial distribution of related time scales was the opposite. The correlations between NDVI and PET, P of cropland vegetation and the time scales related to PET had clear spatial heterogeneity. The time scale of the correlation between NDVI and P for cropland in the northern China was about 2 months. P had a strong influence on the growth of various types of vegetation in the study area, and grassland vegetation was affected by P over the shortest time scale. We compare and analyze the results of this study with other related studies. These results provide a reference for exploring the dynamic changes in different vegetation types and factors impacting them. [ABSTRACT FROM AUTHOR]

Grasslands are crucial ecosystems that provide numerous ecological services and support biodiversity conservation. Grasslands undergo significant threats from both anthropogenic and natural sources, compromising their ability to maintain biodiversity, ecosystem services, and human well-being. However, grasslands are frequently ignored in sustainable development objectives. Adequate knowledge of how grassland degradation affects ecosystem services is essential for sustainable management and grassland ecological restoration. The Kachchh region in western India harbours a unique grassland ecosystem known as the Banni grassland, which once became the finest grassland in Asia. However, undesirable anthropogenic interventions have accelerated its degradation. This research paper aims to assess the suitability of different land areas in Banni for sustainable grassland restoration, considering ecological value as a primary criterion. In the present research, land suitability for grassland management was assessed using a geographical information system (GIS)-based multi criteria evolution (MCE) method with satellite data and the analytic hierarchy process (AHP). The ground truthing of the soil samples was carried out alongside. Slope, rainfall, infiltration rate, LULC, geomorphology, soil texture, soil organic carbon, water holding capacity, SAR, CEC, pH, EC, and soil nutrients were among the criteria used. The weights for each criterion were calculated using a pairwise comparison matrix, and the scores were allocated to sub criteria based on field work, expert opinions, and a literature review. The proposed method can be very useful for evaluating the state of the land and can help with the best possible planning for grassland development and conservation. Banni grassland has the potential to be developed into a critical zone observatory (CZO) in the future, and the present study, with further inputs, holds promise for furthering the cause of its sustainable management. Overall, this study underscores the importance of assessing land suitability for sustainable grassland management and highlights the potential for maximising the ecological value of grasslands in western India and beyond. [ABSTRACT FROM AUTHOR]

Forest–grassland ecotone (FGE) has essential ecological and economic value. Unfortunately, it is impacted greatly by environmental changes and anthropogenic disturbance, and is considered one of the most severely threatened biomes in China. To protect Chinese FGE, identifying its exact boundary and exploring its landscape structure dynamic are badly needed, especially on nationwide scale at one‐year temporal resolution. Here, we mapped the annual FGE distribution of China from 1990 to 2020, investigated its changing trends of area, location and landscape patterns, and revealed the underlying driving factors. Our results showed that FGE area over the 31 years totaled 1 011 870 km2, covering about 10.54% of China's land. The FGE area first increased from 1990 and peaked in 1999, and then kept decreasing until 2020. The FGE gravity center has moved accumulatively 590.15 km over the 31 years, with the net moving distance of 228.76 km southwestward. From 1990 to 2020, forest area increased continuously while grassland and cropland area decreased, but these three landscape types had been dominating the FGE. The increase in forest area was largely converted from grassland. The decline in grassland mainly resulted from its conversion into cropland and forest. Meanwhile, the conversion of cropland to grassland supplemented grassland loss to a certain extent. At landscape level, the total area with decreased fragmentation is larger than that with increased fragmentation. Returning Farmland to Grassland Project and land reclamation were primary drivers for changes of fragmentation in the northern and middle part of the FGE, while temperature and precipitation were primary drivers in southern part. Our results will improve the understanding into the dynamic trends of distribution and pattern of FGE at nationwide scale, and thus help to optimize the designing of ecological projects and protective schemes for FGE as a unique and integral biome. [ABSTRACT FROM AUTHOR]

Ecosystem carbon use efficiency (CUE) is a key parameter in the carbon cycling of terrestrial ecosystems. The magnitude of CUE reflects the ecosystem's potential for CO2 sequestration. China's grasslands play an important role in the carbon cycle. Here, we aimed to investigate the comparation of CUE and its environmental regulation among different grassland in Northern China based on eddy covariance carbon fluxes measurements of 31 grassland sites. The results showed that the average CUE of grassland in Northern China was 0.05 ± 0.22, with a range from −0.42 to 0.66. It was demonstrated that there were significant differences in CUE among different grassland types, and CUE values were ranked by type as follows: alpine grassland > temperate meadow steppe > temperate typical steppe > temperate desert steppe, driven by a combination of climatic, soil, and biological factors, with net ecosystem productivity (NEP) having the greatest impact on them. Except for meadow steppes, moisture had a greater impact on grassland CUE in Northern China than temperature. While temperate desert grassland CUE decreased with increasing soil water content (SWC), the CUE of other grassland types increased with higher precipitation and SWC. These findings will advance our ability to predict future grassland ecosystem carbon cycle scenarios. [ABSTRACT FROM AUTHOR]

Grassy ecosystems cover more than 40% of the world's terrestrial surface, supporting crucial ecosystem services and unique biodiversity. These ecosystems have experienced major losses from conversion to agriculture with the remaining fragments threatened by global change. Woody plant encroachment, the increase in woody cover threatening grassy ecosystems, is a major global change symptom, shifting the composition, structure, and function of plant communities with concomitant effects on all biodiversity. To identify generalisable impacts of encroachment on biodiversity, we urgently need broad‐scale studies on how species respond to woody cover change. Here, we make use of bird atlas, woody cover change data (between 2007 and 2016) and species traits, to assess: (1) population trends and woody cover responses using dynamic occupancy models; (2) how outcomes relate to habitat, diet and nesting traits; and (3) predictions of future occupancy trends, for 191 abundant, southern African bird species. We found that: (1) 63% (121) of species showed a decline in occupancy, with 18% (34) of species' declines correlated with increasing woody cover (i.e. losers). Only 2% (4) of species showed increasing population trends linked with increased woody cover (i.e. winners); (2) Open habitat specialist, invertivorous, ground nesting birds were the most frequent losers, however, we found no definitive evidence that the selected traits could predict outcomes; and (3) We predict open habitat loser species will take on average 52 years to experience 50% population declines with current rates of encroachment. Our results bring attention to concerning region‐wide declining bird population trends and highlight woody plant encroachment as an important driver of bird population dynamics. Importantly, these findings should encourage improved management and restoration of our remaining grassy ecosystems. Furthermore, our findings show the importance of lands beyond protected areas for biodiversity, and the urgent need to mitigate the impacts of woody plant encroachment on bird biodiversity. [ABSTRACT FROM AUTHOR]

Climate warming hampers grassland growth, particularly in dryland regions. To preserve robust grassland growth and ensure the resilience of grassland in these arid areas, a comprehensive understanding of the interactions between vegetation and climate is imperative. However, existing studies often analyze climate–vegetation interactions using concurrent vegetation indices and meteorological data, neglecting time-lagged influences from various determinants. To address this void, we employed the random forest machine learning method to predict the grassland NDVI (Normalized Difference Vegetation Index) in Asian drylands (including five central Asia countries, the Republic of Mongolia, and Parts of China) from 2001 to 2020, incorporating time-lag influences. We evaluated the prediction model's performance using three indexes, namely the coefficient of determination (R2), root-mean-square error (RMSE), and Mean Absolute Error (MAE). The results underscore the superiority of the model incorporating time-lag influences, demonstrating its enhanced capability to capture the grassland NDVI in Asian drylands (R2 ≥ 0.915, RMSE ≤ 0.033, MAE ≤ 0.019). Conversely, the model without time-lag influences exhibited relatively poor performance, notably inferior to the time-lag-inclusive model. The latter result aligns closely with remote sensing observations and more accurately reproduces the spatial distributions of the grassland NDVI in Asian drylands. Over the study period, the grassland NDVI in Asian drylands exhibited a weak decreasing trend, primarily concentrated in the western region. Notably, key factors influencing the grassland NDVI included the average grassland NDVI in the previous month, total precipitation in the current month, and average soil moisture in the previous month. This study not only pioneers a novel approach to predicting grassland growth but also contributes valuable insights for formulating sustainable strategies to preserve the integrity of grassland ecosystems. [ABSTRACT FROM AUTHOR]

Biodiversity is declining at various scales due to habitat simplification. Nevertheless, there is scarce information on how the biotic and abiotic changes linked to simplification affect several diversity dimensions, such as taxonomic, functional, and phylogenetic diversities. This study investigated whether transforming natural oak forests into induced grasslands affected species diversity, functional group structure, and phylogenetic diversity of ant assemblages inhabiting a temperate forest in central Mexico. We placed over 1000 pitfall traps in five sampling events covering a ten‐year period. We used Hill numbers to evaluate species diversity differences between vegetation types and patterns over time. Ant species were classified into stress‐related functional groups, which were analyzed for their association with vegetation types and changes to their proportional abundance over time. We calculated the standardized effect size of the mean nearest taxon distance to quantify the evolutionary history and test for non‐random patterns within vegetation types and sampling years. Species richness did not differ between vegetation types, yet grasslands showed greater diversity for the q = 1 and q = 2 orders. , We also found three ant species as bioindicators for each type of vegetation. Regarding functional structure, cold climate specialists were associated with oak forests. In contrast, generalist species were predominant in induced grasslands. Higher phylogenetic diversity with an overdispersed structure was associated with oak forest, whereas lower phylogenetic diversity and a clustered pattern were found in induced grassland. These results indicate that habitat simplification may not affect the number of ant species, but rather increases their relative abundance and reorganizes the functional and phylogenetic structure in the ecosystem, particularly shifting towards the dominance of evolutionary closely related species and broad‐stress‐tolerant groups. These results highlight the importance of integrating further dimensions of diversity to properly evaluate the reassembly dynamics after habitat simplification, and understand the mechanisms driving this biodiversity loss. [ABSTRACT FROM AUTHOR]

Conservation Agriculture (CA) is actively promoted as an alternative farming system that combines environmental, economic, and social sustainability. Three pillars define CA: (i) minimum mechanical soil disturbance, (ii) permanent soil organic cover, and (iii) species diversification. The local context, constraints, and needs of the farmers influence the translation of the pillars into practices. Currently, there is no method for categorizing this diversity of CA practices, which hampers impact assessment, understanding of farmer choices and pathways, stakeholder communication, and policymaking. This paper presents a systematic method to identify and categorize the diversity of CA practices at the regional level, anchored in the three pillars and based on practices implemented by CA farmers. The classification method is grounded on the intersection of an archetypal analysis and a hierarchical clustering analysis. This method was used to study CA practices in Wallonia, Belgium, based on a survey of practices in a sample of 48 farmers. Combining the two clustering methods increases the proportion of classified farmers while allowing for the distinction between three CA-types with extreme and salient practices, and two intermediate CA-types comprising farmers whose practices fall between these references. The study reveals that three explanatory factors influence the implementation of CA practices in Wallonia: (i) the proportion of tillage-intensive crops and (ii) temporary grasslands in the crop sequence, and (iii) the organic certification. These factors lead to trade-offs that hinder the three pillars of CA from being fully implemented simultaneously. This new classification method can be replicated in other regions where CA is practiced, by adapting input variables according to context and local knowledge. [ABSTRACT FROM AUTHOR]

Grazing management and nitrogen fertilisation may affect forage accumulation (FA), nutritive value, and grazing efficiency (GE) of the highly productive 'Zuri' guineagrass [Megathyrsus maximus (Jacq.) B.K.Simon & S.W.L. Jacobs syn. Panicum maximum Jacq.]. The objective of this study was to assess the effects of pre‐graze canopy heights [55 and 75 cm (H55 and H75, respectively)] and N fertilisation rates [150 and 300 kg N ha−1 year−1 (N150 and N300, respectively)] on FA, GE, grazing losses (GL), and nutritive value of Zuri under rotational stocking. The stubble height was 50% of the pre‐graze canopy height. The total FA was 20% greater under H75 than H55 (22,120 vs. 18,370 kg DM ha−1 year−1), as well as the GL was greater under H75 (85%) than under H55 (79%). Regardless of pre‐graze height, the upper stratum of the canopy was composed mostly of leaves contributing to similar crude protein (CP) (142 g kg−1) and in vitro digestible organic matter (IVDOM) (559 g kg−1) concentrations. Greater N rate (N300) increased FA (23,500 vs. 16,980 kg DM ha−1 year−1) and resulted in greater GE (84% vs. 80%) compared to N150. The CP and IVDOM concentrations under N300 (157 and 571 g kg−1, respectively) were greater than under N150 (128 and 547 g kg−1). Zuri guineagrass grazed at H75 has great FA and GE, maintaining a similar forage nutritive value compared to H55. [ABSTRACT FROM AUTHOR]

Scientists and policymakers are becoming aware of the pressing need to restore tropical grassy biomes (TGB), which are home to unique biodiversity and provide essential ecosystem services to hundreds of millions of people. TGB face increasing threats, including forest‐ and tree‐centric restoration approaches that promote their degradation and we still lack a systematic assessment of where and how TGB restoration research has been done to guide policy and practice.We synthesized knowledge on field restoration experiments by conducting a systematic literature review to map TGB restoration field studies, examine the association of restoration techniques and degradation sources and investigate the diversity of indicators used to monitor restoration outcomes.TGB restoration was concentrated at Brazilian and Australian savannas, with large blindspots in Asia, Africa and northern and western South America. Studies were largely context‐dependent, with an inconsistent usage of restoration techniques to different sources of degradation. Less than half of the indicators evaluated were monitored consistently through time, often using a low‐dimensional approach related to ecosystem functioning. Few studies manipulated fire, herbivores and soils, the key drivers for the re‐establishment of TGB dynamics. Unfortunately, many studies lacked negative (degraded ecosystems), positive (reference ecosystems) controls, or both, impairing attempts to robustly determine restoration outcomes.Our overview of field research on TGB restoration highlights that research needs improvement to refine our ability to assess, plan, implement and monitor restoration. Severe issues with experimental designs and data reporting are identified as barriers to find generality and upscale TGB restoration to meet the goals of the UN Decade on Ecosystem Restoration.Synthesis and applications. Our synthesis calls for enhanced field experiments, transparent data reporting and quantitative syntheses to guide large‐scale TGB restoration. The overall lack of knowledge on improving resilience and measuring outcomes hampers meaningful comparisons between studies and hinders synthetic views essential for determining appropriate restoration techniques for different degradation sources and suitable monitoring indicators. To overcome the scarcity of reliable and transparent data supporting TGB restoration, we propose a simple checklist for minimum research reporting information and more complete multilingual standardized guidelines. [ABSTRACT FROM AUTHOR]

Drought and nitrogen enrichment could profoundly affect the productivity of semiarid ecosystems. However, how ecosystem productivity will respond to different drought scenarios, especially with a concurrent increase in nitrogen availability, is still poorly understood. Using data from a 4‐year field experiment conducted in a semiarid temperate steppe, we explored the responses of aboveground net primary productivity (ANPP) to different drought scenarios and nitrogen addition, and the underlying mechanisms linking soil properties, plant species richness, functional diversity (community‐weighted means of plant traits, functional dispersion) and phylogenetic diversity (net relatedness index) to ANPP. Our results showed that completely excluding precipitation in June (1‐month intense drought) and reducing half the precipitation amount from June to August (season‐long chronic drought) both significantly reduced ANPP, with the latter having a more negative impact on ANPP. However, reducing half of the precipitation frequency from June to August (precipitation redistribution) had no significant effect on ANPP. Nitrogen addition increased ANPP irrespective of drought scenarios. ANPP was primarily determined by soil moisture and nitrogen availability by regulating the community‐weighted means of plant height, rather than other aspects of plant diversity. Our findings suggest that precipitation amount is more important than precipitation redistribution in influencing the productivity of temperate steppe, and nitrogen supply could alleviate the adverse impacts of drought on grassland productivity. Our study advances the mechanistic understanding of how the temperate grassland responds to drought stress, and implies that management strategies to protect tall species in the community would be beneficial for maintaining the productivity and carbon sequestration of grassland ecosystems under climate drought. [ABSTRACT FROM AUTHOR]

Evaluating the impacts of farming systems on biodiversity is increasingly important given the need to stem biodiversity loss, decrease fossil fuel dependency, and maintain ecosystem services benefiting farmers. We recorded woody and herbaceous plant species diversity, composition, and abundance in 43 wetland‐adjacent prairie remnants beside crop fields managed using conventional, minimum tillage, organic, or perennial cover (wildlife‐friendly) land management in the Prairie Pothole Region. We used a hierarchical framework to estimate diversity at regional and local scales (gamma, alpha), and how these are related through species turnover (beta diversity). We tested the expectation that gamma richness/evenness and beta diversity of all plants would be higher in remnants adjacent to perennial cover and organic fields than in conventional and minimum tillage fields. We expected the same findings for plants providing ecosystem services (bee‐pollinated species) and disservices (introduced species). We predicted similar relative effects of land management on alpha diversity, but with the expectation that the benefits of organic farming would decrease with increasing grassland in surrounding landscapes. Gamma richness and evenness of all plants were highest for perennial cover, followed by minimum tillage, organic, and conventional sites. Bee‐pollinated species followed a similar pattern for richness, but for evenness organic farming came second, after perennial cover sites, followed by minimum tillage and conventional. For introduced species, organic sites had the highest gamma richness and evenness. Grassland amount moderated the effect of land management type on all plants and bee‐pollinated plant richness, but not as expected. The richness of organic sites increased with the amount of grassland in the surrounding landscape. Conversely, for conventional sites, richness increased as the amount of grassland in the landscape declined. Our results are consistent with the expectation that adopting wildlife‐friendly land management practices can benefit biodiversity at regional and local scales, in particular the use of perennial cover to benefit plant diversity at regional scales. At more local extents, organic farming increased plant richness, but only when sufficient grassland was available in the surrounding landscape; organic farms also had the highest beta diversity for all plants and bee‐pollinated plants. Maintaining native cover in agroecosystems, in addition to low‐intensity farming practices, could sustain plant biodiversity and facilitate important ecosystem services. [ABSTRACT FROM AUTHOR]

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Livestock congregation areas are nitrous oxide (N2O) hot-spots and could be key areas to focus mitigation action. We tested whether combined cattle urine and fertiliser N2O-N emission factors (EFs) would be higher from a farm gateway area compared to a standard pasture under sub-tropical conditions, and whether the nitrification inhibitor, dimethyl pyrazole phosphate (DMPP), would lower N2O EFs from the gateway area. Treatments (n = 3) included: (i) fertiliser applied to a standard pasture (50 kg urea-N ha−1), (ii) fertiliser (50 kg urea-N ha−1) + urine (350 kg N ha−1) applied to a standard pasture, (iii) fertiliser (50 kg urea-N ha−1) + urine (350 kg N ha−1) applied to the gateway area, and (iv) fertiliser (50 kg urea-N ha−1) + urine (350 kg N ha−1) + DMPP (1.5 kg ha−1) applied to the gateway area. Emissions were monitored via an automated static chamber-based system and 15N-labelled urine treatments (n = 4) used to assess N2O + N2 emissions, N2O:N2 and 15N recovery from the pasture. No significant differences (p > 0.05) were observed for EFs between the fertiliser + urine treatment for the standard pasture (1.10 ± 0.17%) or the gateway area (1.46 ± 0.40%). DMPP did not lower the N2O-N EF from the gateway area (1.50 ± 0.22%), where wet and warm conditions may have accelerated DMPP degradation. In the 15N-labelled urine treatments, significantly (p < 0.05) greater N2O + N2 emissions occurred in the gateway compared to the standard pasture, but disaggregating EFs between the contrasting areas was not warranted. [ABSTRACT FROM AUTHOR]

Seasonal grazing is a recognized and sustainable approach to livestock management, but there is still a lack of comprehensive research on its impact on soil structure. This study utilizes advanced scanning electron microscopy technology to quantitatively evaluate the long-term effects of seasonal grazing on grassland soil structure, focusing on soil pore distribution characteristics and particle size. The investigation offers a detailed visual representation of the arrangement of soil particles at a micro-level. In both grazed and ungrazed plots (NG), soil particles ranging from 0.005 to 0.05 mm and 0.075 to 0.25 mm in size were predominant, constituting 20% and 60%, respectively. In plots subjected to seasonal grazing (grazing in June and August, G68, and grazing in July and September, G79), micro-particles (0.002–0.005 mm) and particles sized 0.05–0.075 mm were significantly lower compared to NG. Scanning electron microscope (SEM) images demonstrate structural differences, with NG displaying a higher proportion of small to medium-sized particles, more small pores, and fewer large pores. Analysis of pore size and morphology reveals the prevalence of large pores in both grazed and ungrazed plots. Continuous grazing plots exhibit significantly higher proportions of large pores compared to NG, while seasonal grazing plots show no significant differences. Correlation analyses indicate associations between soil physicochemical properties, particle size, and pore structure. Total soil nitrogen (TN), total soil carbon (TC), and soil moisture positively correlate with 0.005–0.05 mm particle proportions, while EC is negatively correlated with 0.05–0.075 mm particles. This study enhances our understanding of the effects of grazing practices on soil structure and provides scientific evidence for sustainable land management. [ABSTRACT FROM AUTHOR]

Climate warming has been suggested to impact high latitude grasslands severely, potentially causing considerable carbon (C) losses from soil. Warming can also stimulate nitrogen (N) turnover, but it is largely unclear whether and how altered N availability impacts belowground C dynamics. Even less is known about the individual and interactive effects of warming and N availability on the fate of recently photosynthesized C in soil. On a 10-year geothermal warming gradient in Iceland, we studied the effects of soil warming and N addition on CO2 fluxes and the fate of recently photosynthesized C through CO2 flux measurements and a 13 CO2 pulse-labeling experiment. Under warming, ecosystem respiration exceeded maximum gross primary productivity, causing increased net CO2 emissions. N addition treatments revealed that, surprisingly, the plants in the warmed soil were N limited, which constrained primary productivity and decreased recently assimilated C in shoots and roots. In soil, microbes were increasingly C limited under warming and increased microbial uptake of recent C. Soil respiration was increased by warming and was fueled by increased belowground inputs and turnover of recently photosynthesized C. Our findings suggest that a decade of warming seemed to have induced a N limitation in plants and a C limitation by soil microbes. This caused a decrease in net ecosystem CO2 uptake and accelerated the respiratory release of photosynthesized C, which decreased the C sequestration potential of the grassland. Our study highlights the importance of belowground C allocation and C-N interactions in the C dynamics of subarctic ecosystems in a warmer world.

We present data from producers in the upper Great Plains of the US for whom at least one Conservation Reserve Program (CRP) contract expired in the last seven years. The survey covered two groups, one with a retired CRP contract and a second with a retired CRP contract who then enrolled in the Environmental Quality Incentives Program (EQIP) program. Most respondents at least tried to re-enroll into CRP, many unsuccessfully. The CRP group primarily moved to crops on the former CRP land, while EQIP respondents focused on cattle and grazing. Awareness of the EQIP program on the part of the CRP group was only 58%. We compared groups regarding what they considered doing with the land at the end of their respective programs, CRP and EQIP. We examined group differences in motivations and attitudes and found evidence of convergence. We also evaluated these differences using effect size statistics to determine their importance to our overall questions. Our overall conclusion is that the groups have a long history of program participation and there is little difference between them in both their motivation to participate and willingness to do so in the future.

Abstract Grasslands are crucial ecosystems that provide numerous ecological services and support biodiversity conservation. Grasslands undergo significant threats from both anthropogenic and natural sources, compromising their ability to maintain biodiversity, ecosystem services, and human well-being. However, grasslands are frequently ignored in sustainable development objectives. Adequate knowledge of how grassland degradation affects ecosystem services is essential for sustainable management and grassland ecological restoration. The Kachchh region in western India harbours a unique grassland ecosystem known as the Banni grassland, which once became the finest grassland in Asia. However, undesirable anthropogenic interventions have accelerated its degradation. This research paper aims to assess the suitability of different land areas in Banni for sustainable grassland restoration, considering ecological value as a primary criterion. In the present research, land suitability for grassland management was assessed using a geographical information system (GIS)-based multi criteria evolution (MCE) method with satellite data and the analytic hierarchy process (AHP). The ground truthing of the soil samples was carried out alongside. Slope, rainfall, infiltration rate, LULC, geomorphology, soil texture, soil organic carbon, water holding capacity, SAR, CEC, pH, EC, and soil nutrients were among the criteria used. The weights for each criterion were calculated using a pairwise comparison matrix, and the scores were allocated to sub criteria based on field work, expert opinions, and a literature review. The proposed method can be very useful for evaluating the state of the land and can help with the best possible planning for grassland development and conservation. Banni grassland has the potential to be developed into a critical zone observatory (CZO) in the future, and the present study, with further inputs, holds promise for furthering the cause of its sustainable management. Overall, this study underscores the importance of assessing land suitability for sustainable grassland management and highlights the potential for maximising the ecological value of grasslands in western India and beyond.

The paucity of investigations of carbon (C) dynamics through the soil profile with warming makes it challenging to evaluate the terrestrial C feedback to climate change. Soil microbes are important engines driving terrestrial biogeochemical cycles; their carbon use efficiency (CUE), defined as the proportion of metabolized organic C allocated to microbial biomass, is a key regulator controlling the fate of soil C. It has been theorized that microbial CUE should decline with warming; however, empirical evidence for this response is scarce, and data from deeper soils are particularly scarce. Here, based on soil samples from a whole-soil-profile warming experiment (0 to 1 m, +4 °C) and 18O tracing approach, we examined the vertical variation of microbial CUE and its response to ~3.3-y experimental warming in an alpine grassland on the Qinghai-Tibetan Plateau. Microbial CUE decreased with soil depth, a trend that was primarily controlled by soil C availability. However, warming had limited effects on microbial CUE regardless of soil depth. Similarly, warming had no significant effect on soil C availability, as characterized by extractable organic C, enzyme-based lignocellulose index, and lignin phenol-based ratios of vanillyls, syringyls, and cinnamyls. Collectively, our work suggests that short-term warming does not alter microbial CUE in either surface or deep soils, and emphasizes the regulatory role of soil C availability on microbial CUE.

• Northern and eastern grassland-savanna boundary defined by minimum temperature. • Dynamics of fire, frost and growing season temperatures combine to produce this limit. • Western limit is related to moisture availability. • Modern, high-resolution climate data enables refinement of bioclimatic limits. • Reparameterisation improves global model performance at regional scale. Understanding the controls of biome distributions is crucial for assessing terrestrial ecosystem functioning and its response to climate change. We analysed to what extent differences in climate factors (minimum temperatures, water availability, and growing season temperatures (degree days above 5 °C (GDD5)) might explain the poorly understood borders between grasslands, savannas and shrublands in eastern South Africa. The results were used to improve bioclimatic limits in the dynamic global vegetation model (DGVM) LPJ-GUESS. The vegetation model was also used to explore the role of fire in the biome borders. Results show no clear differences between the adjacent biomes in water availability. Treeless grasslands primarily occur in areas with minimum temperatures and GDD5 values below that of savannas. The standard fire module in LPJ-GUESS is not able to reproduce observed burned area patterns in the study region, but simulations with prescribed fire return intervals show that a combination of low temperatures and fire can explain the treeless state of the grassland biome. These results confirm earlier hypotheses that a combination of low winter temperatures, causing frost damage to trees, and low growing season temperatures that impede tree sapling growth and recruitment, particularly under re-occurring fires, drive the grassland-savanna border. With these insights implemented, the LPJ-GUESS simulation results substantially improved grass distribution in the grassland biome, but challenges remain concerning the grassland-shrubland boundary, tree-grass competition and prognostic fire modelling. [ABSTRACT FROM AUTHOR]

Urban grasslands span climates and topography in soils with variable water infiltration and drainage rates that result in occasional waterlogging stress, while data on grass species tolerance to waterlogging stress is scant. Whole plant responses to waterlogging stress among cool‐season grass species were quantified in a controlled environment. The following grasses were grown in well‐drained vs. waterlogged soil for 55 d: strong creeping red fescue (Festuca rubra ssp. rubra), slender creeping red fescue (F. rubra ssp. littoralis), Chewings fescue (F. rubra ssp. commutata), hard fescue (F. brevipila), tall fescue (F. arundinacea syn. Schedonorus arundinaceus), Kentucky bluegrasses (Poa pratensis), annual bluegrass (P. annua), rough bluegrass (P. trivialis), creeping bentgrass (Agrostis stolonifera), perennial ryegrass (Lolium perenne), and alkaligrass (Puccinellia distans). Five cultivars of each fine fescue (Festuca spp.) taxon were included for comparison. When grown in waterlogged soil compared to well‐drained conditions, relative differences generally ranged from −3% to −26% (shoots) and −13% to −33% (roots) for creeping bentgrass, tall fescue, and Kentucky bluegrass indicating higher waterlogging stress tolerance. The relative differences ranged from −18% to −43% in shoots and −3% to −34% in roots for annual bluegrass and perennial ryegrass indicating fair performance under waterlogging stress. Fine fescues, rough bluegrass, and alkaligrass exhibited the poorest performance during waterlogging stress with plant responses ranging from −12% to −64% (shoots) and −17% to −73% (roots). Negative whole plant responses among cultivars of four fine fescue taxa were similar. The selection of grasses tolerant to waterlogging stress will be important in developing resilient landscapes. [ABSTRACT FROM AUTHOR]

Fire-adaptive traits in plants of tropical and subtropical grassy ecosystems have been the subject of considerable global research, but only recently studied in pyrogenic Florida subtropical grasslands. Plant growth forms, belowground organs, and post-fire recovery strategies were studied for 198 grassland specialists in peninsular Florida. Community types (dry-mesic, mesic, wet-mesic, and wet) were sampled with 1m2 plots along the edaphic-hydrologic gradient and the association between these variables and fire-related plant traits was tested using fourth-corner analysis. Caulescent herbs (43), cespitose graminoids (27), and rosette herbs (31) are the most common growth forms among species sampled. Plants with epigeogenous and hypogeogenous rhizomes dominate the sample plots, including matrix graminoids, shrub geoxyles, and an acaulescent rhizomatous fire-resilient palm (Serenoa repens). Most species (163; 82%) exhibit resprouting, including 30 facultative resprouters and 133 obligate resprouters. All woody rhizomatous species are obligate resprouters, and 35 ephemeral herbaceous species are obligate reseeders. Community type was a better predictor of species abundances than hydrology, however, hydrology was significantly associated with species traits measured, particularly rhizome texture, with woody rhizomes prevalent in all but the wet sites. Belowground organs (xylopodia, geoxylic suffructices) and growth form were associated with frequent fire and phylogeny, suggesting fire regime as a driver of community phylogenetic diversity. Persistence, rapid resilience and co-occurrence of geoxyles align Florida subtropical grasslands with other global geoxyle grasslands. The old-growth, pyrogenic grassy ecosystems of peninsular Florida are the center of geoxyle diversification on the southeastern US coastal plain. [ABSTRACT FROM AUTHOR]