Grassland Management Research Articles

Effect of foraging tunnels created by small subterranean mammals on soil microbial biomass carbon and organic carbon storage in alpine grasslands

Extensive foraging tunnel disturbances created by small subterranean mammals have important impacts on soil physical properties and nutrients in grasslands. This study took plateau zokor (Eospalax baileyi) as an example mammal to investigate the impacts of foraging tunnel disturbances by small subterranean mammals on soil microbial biomass carbon (SMBC) and soil organic carbon (SOC) storage. A paired design was used to locate 90 tunnel quadrats and 90 non-tunnel quadrats in alpine grasslands across three sites. This study showed that SMBC, SOC concentrations and SOC storage in tunnel quadrats were 47.4 %, 26.8 % and 22.0 % lower than those in non-tunnel quadrats, respectively. This study also showed that soil microbial biomass nitrogen was a major factor affecting SOC storage in non-tunnel quadrats, while it was not a major factor in tunnel quadrats. Soil pH and soil ammonium nitrogen were not major factors in non-tunnel quadrats, while they were the major factors influencing SOC storage in tunnel quadrats. In contrast to non-tunnel quadrats, foraging tunnel disturbances led to a new pathway in which soil pH positively affected SOC storage in tunnel quadrats. The findings of this study demonstrated that foraging tunnel disturbances had negative impacts on soil fertility due to lower SMBC concentrations and might cause soil carbon loss in alpine grasslands because of lower SOC storage. Given the effect of foraging tunnels on soil carbon cycling and climate regulation in the Qinghai-Tibet Plateau's alpine grasslands, it is crucial to take them into account when assessing grassland carbon storage and formulating strategies for effective grassland management and conservation.

Soil pH and phosphorus availability regulate sulphur cycling in an 82-year-old fertilised grassland

The application of lime and mineral fertiliser is known to mitigate soil acidification and improve soil quality in improved grasslands. However, the long-term effect of simultaneous lime and fertiliser amendments on soil carbon (C) and sulphur (S) cycling is still poorly understood. To examine if soil pH or nutrient availability are the dominant factors regulating C and S cycling, we evaluated the biodegradation of methionine (organic S), gross S transformation, and microbial S utilisation using 35S and 14C dual-labelling. Soil samples (0–10 cm) were collected from one unfertilised control and five annual limed (Ca) treatments with or without nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) fertilisers (Ca, CaN, CaNP, CaNPKCl, CaNPK2SO4) in an 82-year-old upland grassland experiment in Rengen, Germany. Long-term lime application increased soil pH values but significantly (p < 0.05) decreased soil organic C content. Fertilisation had no significant effect on microbial utilisation of 35S-labelled methionine, while microbial immobilisation of 35SO42− in the limed soils was significantly reduced compared to the control. This is attributed to either the increased soil pH or decreased C availability after liming. Microbial carbon use efficiency (CUE) was significantly higher in soils with applied P fertiliser (i.e., CaNP: 0.66 ± 0.02, CaNPKCl: 0.68 ± 0.02, CaNPK2SO4: 0.65 ± 0.01) compared to the CaN treatment (0.58 ± 0.01). Moreover, compared to CaN, CaNP and CaNPKCl treatments significantly increased gross S turnover, while no significant effects were observed in the CaNPK2SO4 treatment. Soil P deficits decreased microbial CUE and S bioavailability. Although P fertiliser addition alleviated microbial P limitation when N fertiliser was added, S fertiliser (CaNPK2SO4) present constrained S transformation rates. Overall, the importance of P availability for global S cycling in grasslands is shown, especially under N-enrichment conditions. However, the subsequent potential for C loss from long-term liming should be carefully considered in grassland management.

Heterogeneity is key to supporting forest-dweller butterflies

Worldwide, forests are considered biodiversity hotspots. Butterflies are among the surrogate species for forest biodiversity yet in many parts of the world, little is known about the presence or habitat use of forest-dweller butterflies. In this study we aimed to narrow the information gap by applying a time-effective butterfly survey in forests in northeast Türkiye that are surrounded by several prime butterfly areas. The target species were Boloria euphrosyne, Coenonympha arcania, Erebia aethiops, and Satyrium ilicis. The surveys provided 128 records of the species. Random forests models showed that the mean temperature of the warmest month, canopy cover of pine trees, tree size, and managed meadows in or at the edge of forests are important parameters for species occurrence. Nevertheless, the direction of the effects varied between species. Maintaining heterogeneity in forests in terms of the forest variables indicated above and promoting small-scale grassland management in forest openings and edges are important conservation measures for forest-dwelling butterflies. The relevance of the temperature suggests that climate change may have significant effects on the occurrence of forest butterflies. Key words: Habitat use, Hay meadows, Forest structure, Erebia aethiops, Satyrium ilicis, Coenonympha arcania

Effect of Management of Grassland on Prey Availability and Physiological Condition of Nestling of Red-Backed Shrike Lanius collurio.

The study aimed to determine the influence of grassland management on the potential food base of the red-backed shrike Lanius collurio and the condition of chicks in the population inhabiting semi-natural grasslands in the Narew floodplain. The grassland area was divided into three groups: extensively used meadows, intensively used meadows fertilised with mineral fertilisers, and intensively used meadows fertilised with liquid manure, and selected environmental factors that may influence food availability were determined. Using Barber traps, 1825 samples containing 53,739 arthropods were collected, and the diversity, abundance, and proportion of large arthropods in the samples were analysed depending on the grassland use type. In the bird population, the condition of the chicks was characterised by the BCI (Body Condition Index) and haematological parameters (glucose level, haemoglobin level, haematocrit, and H:L ratio). The diversity of arthropods was highest in extensively used meadows. Still, the mean abundance and proportion of arthropods over 1 cm in length differed significantly for Orthoptera, Hymenoptera, Arachne, and Carabidae between grassland use types, with the highest proportion of large arthropods and the highest abundance recorded in manure-fertilised meadows. The highest Body Condition Indexes and blood glucose levels of nestlings indicating good nestling nutrition were recorded in nests of birds associated with extensive land use. The H:L ratio as an indicator of the physiological condition of nestlings was high on manure-fertilised and extensively managed meadows, indicating stress factors associated with these environments. This suggests that consideration should be given to the effects of chemicals, such as pesticides or drug residues, that may come from slurry poured onto fields on the fitness of red-backed shrike chicks.

Breeding biology of the Ochre-breasted pipit (Anthus nattereri), with notes on its conservation in the Upper Rio Grande Grasslands, south-eastern Brazil

ABSTRACT The Ochre-breasted pipit Anthus nattereri is a terrestrial bird restricted to natural grasslands of south-eastern South America. The species is globally Vulnerable to extinction and its natural history is still poorly known. We investigated the breeding biology of Ochre-breasted pipits, commenting on its habitat use and the potential impacts of local grasslands management practices with fire on the species’ conservation. Fieldwork took place mainly between January and December 2016 in the Upper Rio Grande Grasslands, south-eastern Brazil. Five nests of the species were found between September and November, one of them recently destroyed by fire. Nests were cup shaped and placed on the ground, being built with dry grasses, resembling the pattern documented for other species of Anthus. The eggs were covered with brownish spots and dots to a variable extent and the background colour ranged from greyish white to brownish white. The egg colour pattern also fell within the known range of variation for congeneric species, as did the clutch size (two to three eggs) observed in tropical species of Anthus. Ochre-breasted pipits tended to occupy nesting sites with higher and denser grass cover (eg small patches of vegetation that survived the last fire event) when compared to non-nest sites located in adjacent recently burned areas, which potentially suggests a preference for such habitat attributes. Although the Ochre-breasted pipit is relatively common in the study area, the highest temporal incidence of fire coincides with its breeding season, which can directly impact the local population through the burning of nests and the elimination of suitable nesting sites. Thus, it is important to conduct long-term studies to evaluate the impact of different fire regimes on the reproductive performance of Ochre-breasted pipits, thus allowing the design of better ecosystem management practices to guarantee its conservation.

Recreation and its synergies and trade-offs with other ecosystem services of Alpine and pre-Alpine grasslands

Alpine and pre-Alpine grasslands provide numerous ecosystem services including provisioning services (e.g. fodder production), regulating services (e.g. soil erosion reduction), and cultural services (e.g. recreation). While intensively managed grasslands specifically target the production of fodder, more extensively used grasslands are known for being hotspots of biodiversity. However, there is a need to better understand the relationship among the supply of ecosystem services, specifically regarding the use of grasslands for cultural ecosystem services such as recreation. In this study, we investigated the synergies and trade-offs of ecosystem services and analyzed underlying variables related to the recreational use of grasslands. We investigated the supply of recreation (indicated by Photo-User-Days from geo-tagged photos on grasslands), fodder production (indicated by yield), and regulating and habitat ecosystem services (indicated by agri-environmental payments), and analyzed their relationship to management-related variables with a Redundancy Analysis. To better explain the recreational use of grasslands, we further analyzed how environmental and infrastructural features influence the occurrence of Photo-User-Days with a hurdle regression. Finally, we conducted spatial analyses to understand the distribution of Photo-User-Days in space. We found a weak but significant negative relationship between Photo-User-Days and yield, which implies that people slightly prefer extensive grassland to intensive grassland for recreation. Our results also show that agri-environmental schemes targeted towards extensive grassland management can positively influence the recreational use. Other factors, such as proximity to touristic features (e.g. castles), presence of infrastructural features (e.g. cable cars), and environmental characteristics (e.g. low share of croplands, distance to forests), also influenced the spatial distribution of photos on grasslands. The importance of these factors underscores the value of grasslands as a component of the cultural landscape for recreational purposes. These results also suggest that cultural ecosystem services of grasslands can be considered to be co-produced by natural, social, and infrastructural components. The study further discusses limitations to the explanatory power of geo-tagged photo analysis to determine the wide range of cultural ecosystem services of grasslands. We conclude that grasslands play an important role for recreation in (pre-)Alpine landscapes, which can also be effectively supported through targeted agri-environmental payments.

Litter accumulation suppresses grass production but facilitates shrub expansion in a long‐term fenced grassland

AbstractShrub expansion is increasing in grasslands worldwide and has profound effects on biodiversity and ecosystem functions. Shrub expansion has primarily been explained by extrinsic factors such as climate change and human activities, yet the roles of intrinsic shrub demographic population dynamic and shrub–grass interaction remain poorly understood. With a paired mown and exclosure comparison experiment and baseline levels of shrub abundance in a semiarid grassland, we confirmed that long‐term livestock exclusion promotes expansion of two native shrubs, Artemisia sacrorum and Caragana brachypoda. Shrub abundance increased during the livestock exclusion period. Shrub biomass in fenced plots was about 5‐ to 10‐fold greater than in mown plots. Both increase in population density and individual size (especially height) contributed to shrub increase. The mechanism behind this was the divergent effects of litter accumulation on shrubs and grasses. Litter accumulation suppressed grass production, while facilitating shrub recruitment and growth. Our findings highlight the potential role of litter accumulation‐mediated shifts in shrub–grass interactions, which should be incorporated into grazing top‐down control to better predict the restoration outcomes of grassland management changes. The identified internal biotic mechanism raises the possibility that removal of accumulated litter by grazing or mowing may be an alternative way to maintain or restore a grass‐dominated state in shrub expansion areas.

Using Prescribed Fire and Biosolids Applications as Grassland Management Tools: Do Wildlife Respond?

Prescribed burning is a management tool commonly used in forested ecosystems in the southeastern United States, but the influence of this method on grassland vegetation and wildlife in this geographic region is unknown. During 2009–2015, we conducted a study to determine if the application of prescribed burning and/or long-term biosolid applications alter plant communities and/or wildlife use of grassland areas at Marine Corps Air Station Cherry Point, Havelock, NC. We monitored vegetation growth, measured plant community composition, and documented wildlife activity in four study plots for 3 years after the implementation of annual winter prescribed burns. Prescribed burning reduced the amount of litter, increased bare ground during spring, and altered the plant community composition relative to areas that were not burned. Overall, prescribed burning did not alter (F1,803 = 0.37, p = 0.54) bird use of the airfield grasslands, while the long-term application of biosolids resulted in higher (F1,803 = 17.61, p &lt; 0.01) bird use. Few species-specific differences in avian use of prescribed burned and unburned grasslands were found. In contrast, white-tailed deer (Odocoileus virginianus) use of areas that were burned in winter, as well as the adjacent unburned areas, was drastically reduced. Winter prescribed burning appeared to remove forage plants at the time of year deer would use them the most. Our findings suggest that prescribed burning and biosolid applications, used alone and in combination, might be viable grassland management tools for altering wildlife use of grassland areas, specifically white-tailed deer; however, similar research at additional locations should be conducted.

Study on Improvement of Status Survey Form for the Effective Management of Grassland

Study on Improvement of Status Survey Form for the Effective Management of Grassland

A study on ecohydrological mutual feedback relationship of the Shangdong River basin based on hydrological connectivity

Investigating eco-hydrology in desert grasslands is pivotal to comprehend the dynamic evolution patterns of vegetation. Nonetheless, a research void persists in understanding the eco-hydrological mutual feedback mechanisms associated with hydrological connectivity and the corresponding health index evaluation of a small watershed. This study is centered on the Shangdong River watershed in Inner Mongolia and uses SWAT (Soil and Water Assessment Tool) to simulate hydrological processes. The hydrological connectivity index (IC) was employed as a link to conduct Pearson correlation analysis and Granger causality tests on ecological and meteorological-hydrological factors. Additionally, the PSR model was utilized to assess the ecological health status of the watershed. Key findings reveal the following: (1) The NDVI in the Shangdong River watershed showed an overall upward trend from 2007 to 2018, while IC exhibited an overall downward trend. Temporally and spatially, there was a significant negative correlation between IC and NDVI. (2) During the vegetation growth season, IC serves as a pivotal link in the feedback loop of eco-hydrological processes. Temperature drives vegetation growth, which in turn affects IC. IC regulates soil moisture content and evaporation, further influencing vegetation growth, thus forming a feedback mechanism. (3) Over the study period, the Grassland Health Composite Index (GHI) demonstrated a consistent rise, averaging 0.44, signaling a suboptimal state for the grassland ecosystem. Furthermore, a negative correlation was observed between GHI and IC. Consequently, regulating IC could play a crucial role in safeguarding and rejuvenating the grassland ecosystem. This study offers theoretical and data support for understanding eco-hydrological processes and effective pasture management of the desert grassland watershed.

Forage plants in grasslands with different topographies affect yak foraging preferences on the eastern Tibetan plateau.

Diet selection, a core problem of foraging behavior, is a nutritional adaptation strategy formed in the long-term natural selection process by grazing herbivores and is significant for the sustainable management of grassland. Studies have mainly focused on the impacts of the individual and whole community spatial characteristics and herbivore body status on herbivore foraging behavior; thus, the response and mechanism of forage plants in different terrains to the diet selection of grazing herbivores remains unclear. Therefore, in this study, forage plants (gramineae, cyperaceae, legume, forbs, edible shrubs, and community) in different topographies (terrace, riparian zones, shady slope, half shady slope, half sunny slope, sunny slope) on the eastern Tibetan plateau were selected to study changes in nutrient and mineral content characteristics of forage plants, as well as the difference in feeding bias of yaks for forage plants in different terrains by using an indoor cafeteria trial. A structural equation model was used to illustrate the impact of the forage plants in different terrains on the feeding bias of yak. The multi-criterion decision model TOPSIS showed that the nutritional value of gramineae was highest for the shaded slope, and that of cyperaceae and leguminosae was the highest for the terraces. The nutrient value of forbs and the whole community was highest for the sunny slope. Dry matter intake by yaks of leguminosae, forbs, and the whole plant community was significantly higher for terraces than for grasslands with other topographies, and all were significantly lower in riparian zones. Yak forage preference of leguminosae, forbs, and the whole community was the highest for the terrace and the lowest for the riparian zones. Structural equation modeling showed that for functional groups, the interactions between topography and functional groups were the drivers influencing yak forage preferences. Our study highlights the propensity of yaks to forage for plants in areas with different topographies. These results have provided a scientific basis for understanding the relationship between herbivores and plants in grasslands and for formulating scientific grazing management strategies, which are of considerable importance for sustainable grassland livestock husbandry.

Root‐zone enrichment of soil organic carbon and nitrogen under grazing and other land uses in a humid‐temperate region

AbstractGrazing lands can be considered a conservation land use providing value to farmers and society. An underappreciated value of these lands may be in C and N storage and cycling. However, soil organic C (SOC) and total soil N (TSN) storage under humid‐temperate zone pastures have not been well characterized. A survey of 31 farms in Virginia USA characterized SOC and TSN depth distributions under a diversity of grassland management scenarios, as well as in comparison with long‐term no‐till cropland and woodland uses on the same farms. Root‐zone enrichment calculations separated management‐controlled SOC and TSN stocks from a baseline condition characterized at 30‐cm depth. Total stock of SOC at 0–30‐cm depth varied from 46 to 88 Mg C ha−1 (5%–95% range from 304 soil profiles) across all land uses. Root‐zone enrichment of SOC was maximized under mature pastures (≥20 years old) at 38.3 ± 1.6 Mg C ha−1, which was not different from that under woodland (39.8 ± 1.2 Mg C ha−1), but was greater than under no‐till cropland (28.3 ± 1.3 Mg C ha−1) and conventional‐till cropland (15.1 ± 5.1 Mg C ha−1). Root‐zone enrichment of TSN was optimized at stocking rate of ~1 Mg live weight ha−1, but was not affected by stocking method, N fertilization history, or low levels of hay feeding. These results suggest that grazed pastures in Virginia are storing significant amounts of SOC and TSN, with at least half due to management‐induced compared with pedogenic‐controlled accumulation.

Seminatural Grasslands: An Emblematic Challenge for Nature Conservation in Protected Areas

Seminatural grasslands are among the most threatened habitats in Europe and worldwide, mainly due to changes in/abandonment of their traditional extensive use by grazing animals. This study aimed to develop an innovative model that integrates plant biodiversity, animal husbandry, and geo-informatics to manage and preserve seminatural grasslands in protected areas. With this objective, an integrated study was conducted on the seminatural grasslands in the hilly, montane, and (to a minimum extent) subalpine belts of the Maiella National Park, one of Europe’s most biodiversity-rich protected sites. Plant biodiversity was investigated through 141 phytosociological relevés in homogeneous areas; the pastoral value was calculated, and grasslands’ productivity was measured together with the main nutritional parameters. Uni- and multivariate statistical analyses were performed to identify the main grassland vegetation types, their indicator species and ecological–environmental characteristics, and their pastoral and nutritional values’ variability and differences. A total of 17 grassland types, most of which correspond to habitat types listed in Annex I to the 92/43/EEC Directive, were identified and characterised in terms of their biodiversity and potential animal load. To allow for near-real-time analysis of grasslands, an NDVI-based web interface running on Google Earth Engine was implemented. This integrated approach can provide decision-making support for protected-area managers seeking to develop and implement sustainable grassland management practices that ensure the long-term maintenance of their biodiversity.

Effects of dairy farming management practices on carbon balances in New Zealand’s grazed grasslands: Synthesis from 68 site-years

Globally, the soils underlying managed grasslands are an important reservoir of carbon (C), with the management of the land strongly influencing whether the soils gain, lose or maintain C. Further, improved grassland management, such as rotational grazing and increased sward diversity, are widely promoted to increase soil C sequestration despite limited evidence. Using data from New Zealand’s grazed dairy grasslands, we examined the effect of management practices on C stocks through measurement of the net ecosystem C balance (NECB) across 68 site-years. Management practices tested included year-round rotational grazing, differing pasture sward composition, irrigation, periodic supplemental feed cropping and pasture renewal. Excluding years where supplemental feed cropping occurred, the mean (±95% confidence interval) NECB was −12 ± 30 g C m−2 y−1 (65 site-years; the negative value represents C loss), indicating the soil C stocks of these ecosystems were likely near steady-state. The processes of pasture renewal and the transition between pasture and crops resulted in reduced C inputs from photosynthesis of between −232 and −94 g C m−2. This reduced C input was partially overcome with the application of effluent or manure at the time of cultivation where applied. There was no difference in NECB between irrigated (−26 ± 114 g C m−2 y−1) and non-irrigated (−19 ± 198 g C m−2 y−1) pastures. In general, conventional ryegrass/white clover pastures were more beneficial for C stocks than alternative pasture species and mixes. Periodic cropping for supplemental feed resulted in C losses, with the magnitude depending on crop type and management, although data were limited to three site-years.

Sustainable Grassland-Management Systems and Their Effects on the Physicochemical Properties of Soil.

Grassland covers approximately 17.4% of Europe's land area, stores about 20% of the world's soil carbon and has the potential to sequester carbon. With the help of sustainable management systems, grasslands could reduce greenhouse gases and act as a terrestrial sink for atmospheric CO2. In this study, we will investigate the effect of grassland management (cutting, grazing, and a combination of the two) and soil depth (0-10, 10-20, 20-30 cm) on the physical (volumetric water content-VWC, bulk density-BD, porosity-POR, mass consisting of coarse fragments-FC) and chemical properties of soil (organic carbon-SOC, inorganic carbon-SIC, total carbon-STC, total nitrogen-STN, organic matter-SOM, C/N ratio, pH) in Central European lowlands. The management system affected BD, SOC and STN and tended to affect VWC and STC in the first soil depth only. Grazing and the combined system stored greater amounts of STN, SOC and STC and had higher BDs at the surface (0-10 cm) compared to the cutting system. Most soil properties were influenced by soil depth, with C/N ratio and BD increasing and SOC, STC, STN, SOM, VWC and POR decreasing with depth. Our study highlights an opportunity for grassland users to improve soil quality, reduce fossil fuel usage and improve animal welfare through their management systems and argues that systems such as grazing and the combined system should be promoted to mitigate climate change.

Convolutional transformer attention network with few-shot learning for grassland degradation monitoring using UAV hyperspectral imagery

ABSTRACT In recent years, the desertification of grasslands has increased due to various factors, including both global warming and human activities. It is an essential basis for grassland degradation monitoring to monitor the dynamic change of desert grassland vegetation communities and distribution statistics. Although unmanned aerial vehicle (UAV) remote sensing images have allowed us to achieve dynamic real-time grassland monitoring, the distribution of desert grassland ground objects can be random and narrow, thus increasing the difficulty of sample labelling of remote sensing imagery. Therefore, to reduce the number of samples required for the model, this research proposes a convolutional transformer attention network (CTAN) to identify desert grassland ground objects and validate it on a self-collected desert grassland dataset. The network utilizes the transformer model to enhance its learning of global pixels so that it suppresses the transmission of background pixels within the network. Furthermore, the edge convolution module is designed to strengthen the network’s learning for edge pixels, improving its identification effect. The results show that the network provides 97.22% of overall accuracy (OA), 94.35% of average accuracy (AA), and 0.9398 of Kappa for ground object recognition in desert grassland. The model improves OA by 2.36–9.85% points compared to methods in the same field and 0.8–6.35% points compared to methods in hyperspectral imagery classification. The experimental results show the superior performance of the CTAN model for recognizing desert grassland objects, which helps the management and restoration of desert grasslands.

Heavy grazing reduces soil bacterial diversity by increasing soil pH in a semi-arid steppe.

In a context of long-term highly intensive grazing in grassland ecosystems, a better understanding of how quickly belowground biodiversity responds to grazing is required, especially for soil microbial diversity. In this study, we conducted a grazing experiment which included the CK (no grazing with a fenced enclosure undisturbed by livestock), light and heavy grazing treatments in a desert steppe in Inner Mongolia, China. Microbial diversity and soil chemical properties (i.e., pH value, organic carbon, inorganic nitrogen (IN, -N and -N), total carbon, nitrogen, phosphorus, and available phosphorus content) both in rhizosphere and non-rhizosphere soils were analyzed to explore the responses of microbial diversity to grazing intensity and the underlying mechanisms. The results showed that heavy grazing only deceased bacterial diversity in the non-rhizosphere soil, but had no any significant effects on fungal diversity regardless of rhizosphere or non-rhizosphere soils. Bacterial diversity in the rhizosphere soil was higher than that of non-rhizosphere soil only in the heavy grazing treatment. Also, heavy grazing significantly increased soil pH value but deceased NH4+-N and available phosphorus in the non-rhizosphere soil. Spearman correlation analysis showed that soil pH value was significantly negatively correlated with the bacterial diversity in the non-rhizosphere soil. Combined, our results suggest that heavy grazing decreased soil bacterial diversity in the non-rhizosphere soil by increasing soil pH value, which may be due to the accumulation of dung and urine from livestock. Our results highlight that soil pH value may be the main factor driving soil microbial diversity in grazing ecosystems, and these results can provide scientific basis for grassland management and ecological restoration in arid and semi-arid area.

Defoliation modifies the response of arbuscular mycorrhizal fungi to drought in temperate grassland

Arbuscular mycorrhizal (AM) fungi predominate in grasslands, where they play a key role in enhancing plant water uptake and plant tolerance to drought. However, how plant defoliation, which is common to grazed and cut grasslands, modifies plant and AM fungi responses to drought remains unknown. Here, we examined how defoliation intensity modified plant and AM fungi responses to drought.This was done using an in situ factorial field experiment at Colt Park meadows, northern England, whereby mixed grassland communities were subjected to different intensities of defoliation in combination with simulated summer drought. We measured a range of plant, AM fungal, and soil microbial and chemical responses to defoliation and drought, both individually and in combination, and extracted neutral lipid fatty acid (NLFA) as an indicator of AM fungi energy storage status.High intensity defoliation significantly reduced root colonization by AM fungi, and the negative impact of drought on AM fungi extraradical hyphal length was amplified under high intensity defoliation. Drought had no effect on total shoot biomass but reduced specific root length and increased soil NLFA concentrations, indicating an increase in AM fungi energy reserves. However, defoliation dampened this response, implying that defoliation suppresses AM fungi energy reserves under drought.Our findings suggest that plant communities can maintain above-ground productivity under drought with the assistance of AM fungi symbiosis, but that defoliation suppresses positive plant-fungi interactions under drought. Taken together, our findings provide new insights into how drought and defoliation, a key feature of grassland management, combine to negatively impact the plant-AM fungi associations in grassland.

Microtopography causes small‐scale variation in harvest and forage quality of high‐yielding silage grassland in northern Germany

AbstractBackgroundLocal sward dieback, especially in grasslands on peat soil, in response to the extreme 2018/2019 drought demonstrates climate vulnerability of intensive grasslands in northern Central Europe.MethodsWe explore the influence of microtopography, that is, the within‐field mosaic of depressions and elevated patches, on soil volumetric moisture content, standing biomass and biomass crude protein (CP) and fibre content in intensively managed grassland on peat soil in a moist year (2021) and a dry year (2022) for quantifying small‐scale spatial heterogeneity within a field.ResultsWe found high within‐field variation in soil moisture, biomass and forage quality and a moisture dependence of productivity that was stronger in the dry year. CP ranged from 10% to 25% within a field, being lower in moist depressions than elevated patches in the wet (but not in the dry) summer.ConclusionsThe moister depressions help to limit the overall productivity decline in dry summers, whereas, in moist summers, the higher dry patches produce more protein‐rich forage than the depressions, where productivity is higher but quality is lower. We recommend adapting grassland management to this heterogeneity through spatially differentiated management regimes in order to better cope with an increasingly drier and more variable climate.

A more effective approach for species-level classifications using multi-source remote sensing data: Validation and application to an arid and semi-arid grassland

The distribution of grassland communities significantly influences biodiversity conservation and resource management. Remote sensing datasets, such as Sentinel land cover images with high spatial and temporal resolution, have been commonly employed to simulate the distribution and community structure of plant species in grasslands. Nevertheless, the precision of grassland and community classification requires further enhancement for more effective grassland management. In response, our study presents a dynamic workflow for simulating the distribution of grassland plant species under different hydroclimatic conditions. Leveraging a random forest classifier with multi-source remote sensing features, we mapped the distribution of nine plant communities and six types of land cover in the upstream grasslands of the Xilingol River Basin, Inner Mongolia from 2017 to 2022. Utilizing the Google Earth Engine platform, our findings reveal a remarkable consistency in the overall spatiotemporal accuracy and classification precision of grassland communities across different years, even under varying hydroclimatic conditions. When critical features were carefully selected, the integration of Sentinel-1 (C-band synthetic aperture radar), Sentinel-2 (surface reflectance), SRTM DEM 30 m (Digital Elevation Model data), and MOD16A2.006 (evapotranspiration/latent heat flux product) data yielded a high overall accuracy ranging from 87.0 % to 89.5 % over multiple years. Our study not only determined the spatial patterns of various grassland plant communities but also explored the mechanism of their responses to different hydroclimatic conditions. The proposed approach holds practical implications for fine-scale grassland classification, providing valuable support for landscape classification and monitoring efforts. Furthermore, the insights derived from our findings offer valuable guidance for land managers and policymakers, aiding them in making informed decisions related to grassland conservation and sustainable land use planning.