Peatlands contribute significantly to global CH₄ emissions and understanding microbial pathways and drivers of CH₄ emissions is essential for both constraining sources and for mitigation efforts. Stable isotopes are widely used to constrain contributions from different emission sources but are often assumed to be constant over time. Few studies have investigated temporal changes in isotope ratios of emissions from peatland ecosystems. We conducted a 2.5-year study investigating seasonal change in CH₄ fluxes and dual-stable isotopes (δ¹³C, δ²H) in an ombrotrophic peat bog in Northern England. We performed chamber flux measurements and incubation experiments to quantify CH₄ and CO₂ fluxes, CH₄ isotopes, and CH₄ production and oxidation potential. CH₄ fluxes varied significantly across seasons and years, with exceptionally high emissions (>45,000 µmol m⁻² h⁻¹) recorded in summer 2016, contrasting with median fluxes of 10.6–91.8 µmol m⁻² h⁻¹. Fluxes correlated with soil solution chemistry and soil temperature but not with water table depth which had limited variability. Laboratory CH₄ production potentials peaked below the water table at 30-40 cm depths, while oxidation potential decreased with depth. Carbon and hydrogen isotopes showed opposing trends as ẟ¹³C increased with CH₄ flux while ẟ²H decreased. This is consistent with increasing fluxes being driven by acetoclastic methanogenesis. Our results highlight that seasonal shifts in CH₄ emissions are accompanied by changes in isotopic signatures, even without major changes in water table or CH₄ oxidation. Incorporating temporal variability into isotope-based CH₄ source attribution may therefore improve constraints on peatland emissions in global CH₄ budgets.

Abstract. The native pinewoods of Scotland are acknowledged to be an important ecological resource, both for their biodiversity value and as a cultural and amenity resource. Due to the unique nature of the habitat and its limited range, it plays a critical role as an early warning system for broader environmental issues. In the late 1960s and 70s, increased concern was expressed regarding a decline in the status and management of the pinewoods. In response to the concerns, an ecological monitoring survey was initiated by R.G.H. Bunce of the Nature Conservancy in 1971, recording ground flora, tree information, soils and other descriptive attributes. Since that time, interest in the pinewoods has increased further, and there is a general consensus that the habitat is more vulnerable than ever. Thanks to a recent repeat survey between 2018 and 2022, questions addressing the threats and changes occurring in the pinewoods can now be explored in a statistically robust way. These questions include issues surrounding the impacts of deer grazing, regeneration, the balance between native and exotic species, local disturbances, trends in ground flora species occurrences, climate change and recovery from acidification. The new data from the 2018–22 survey are now publicly available via the following DOI: https://doi.org/10.5285/5e268e86-4a4f-4112-bf2d-c3b0179c915c ‘Habitat, vegetation, tree and soil data from Native Pinewoods in Scotland, 2018–2022’.

The need to combat widespread degradation of grassland ecosystem services makes grassland restoration a global sustainability priority. However, simultaneously enhancing multiple ecosystem services (i.e. ecosystem service multifunctionality) is a major challenge for grassland restoration due to trade-offs among services. We use a long-term multifactor grassland restoration experiment established in 1989 on agriculturally improved, species-poor grassland in northern England, to assess how increasing the number of restoration treatments, including addition of manure, inorganic fertiliser, a seed mixture, and promotion of a nitrogen-fixing legume (Trifolium pratense), affects ecosystem service multifunctionality, based on 26 ecosystem service indicators measured between 2011 and 2014. We find that single interventions usually lead to trade-offs among services and thus have few positive effects on ecosystem service multifunctionality. However, ecosystem service multifunctionality increases with the number of restoration interventions, as trade-offs are reduced. Our findings highlight the significant potential for combined use of multiple targeted interventions to aid the restoration of ecosystem service multifunctionality in degraded grasslands, and potentially, other ecosystems.

Characterising methane (CH4) sources and their stable isotope values at the regional level is important for taking effective mitigation actions as well as more accurately constraining global atmospheric CH4 budgets. We performed dual stable isotope (13C, 2H) analysis of CH4 emission sources as well as mobile 13C measurements in North-West England, in a region with a mix of natural and anthropogenic emission sources as well as potentially exploitable shale gas deposits. Dual isotope analysis was performed for enteric fermentation, animal waste, landfill gas, wetlands, and natural gas from the regional distribution network. Microbial emission sources' 813C values ranged from -72.1 +/- 0.31%o to -53.1 +/- 1.17%o with agricultural sources and landfills showing partially overlapping values (-65.3 +/- 0.41%o to -72.1 +/- 0.31%o and -59.2 +/- 0.26%o to -70.4%o, respectively). However, the use of a dual isotope approach with 82H provided additional separation between agricultural (-340 +/- 0.8%o to -322 +/- 19.5%o) and landfill (-312 +/- 0.3%o to -282%o) CH4. All microbial sources were clearly distinct from natural gas with mean values of -39.5 +/- 1.38%o and -184 +/- 4.9%o for 813C and 82H, respectively. Mobile measurements conducted over a distance of 557 km detected emissions from two out of four surveyed managed landfills in the region. Multiple gas leaks were detected, which may confound emissions from other thermogenic sources. When separating the surveyed area by land-use into agricultural and urban, we found that background levels of CH4 were more depleted by around 1%o in areas with agricultural land use compared to urban areas, but emissions from gas leaks and landfills are present in both categories. Our findings highlight the complexity of isoscapes in regions with multiple types of emission sources and the value of dual-isotope measurements in source attribution.

A common practice used to restore and maintain biodiversity in grasslands is to stop or decrease the use of fertilizers as they are a major cause of biodiversity loss. This practice is problematic for farmers who need fertilizers to increase forage and meet the nutritional needs of livestock. Evidence is needed that helps identify optimal fertilizer regimes that could benefit biodiversity and livestock production simultaneously over the long-term. Here, we evaluated the impact of different fertilizer regimes on indicators related to both biodiversity (plant, pollinator, leaf miners and parasitoid Shannon-Weiner diversity, bumblebee abundance, nectar productivity and forb species richness), and forage production (ash, crude protein, ruminant metabolizable energy and dry matter). To this end, we used data from a grassland restoration experiment managed under four nutrient inputs schemes for 27 years: farmyard manure (FYM; 72 kg N ha-1 yr-1), artificial nitrogen-phosphorus and potassium (NPK; 25 kg N ha-1 yr-1), FYM + NPK (97 kg N ha-1 yr-1) and no-fertilizer. Results showed strong trade-offs between biodiversity and forage production under all treatments even in applications lower than the critical load in the EU. Overall, farmyard manure was the fertilizer that optimized production and biodiversity while 97 kg N ha-1 yr-1 of fertilizer addition (FYM+NPK) had the most negative impact on biodiversity. Finally, forage from places where no fertilizer has been added for 27 years did not meet the nutritional requirements of cattle, but it did for sheep. Rethinking typical approaches of nutrient addition could lead to land management solutions suitable for biological conservation and agriculture.

A common practice to restore and preserve grasslands is to stop or decrease the use of fertilizers as they are a major cause of biodiversity loss. This practice, though, is problematic for farmers who need fertilizers to increase forage and meet the nutritional needs of livestock. Evidence is needed that helps identify optimal fertilizer regimes that could benefit biodiversity and livestock production simultaneously over the long-term. Here, we evaluated the impact of different fertilizer regimes on different ecosystem attributes supporting both insect biodiversity and livestock production using data from a grassland restoration experiment managed under four nutrient inputs schemes for 27 years. Overall, farmyard manure was the fertilizer that optimized production and biodiversity, although, biodiversity (plant and insect communities) reached maximum values under no fertilizer use. Varying fertilizer regimes are needed to maintain biodiversity and production on working farms. No fertilizer use is needed to preserve and restore plant species richness and pollinator diversity, while organic fertilizer inputs were necessary to maintain sustainable livestock production and enhance percent parasitism of herbivorous insects. Finally, we showed that forage could be suitable for livestock with no nutrient input, but this requires rethinking the typical approach of adapting forage to livestock needs, to one of adapting the livestock type to the existing forage.

Recent research has used mobile methane (CH4) measurements to identify and quantify emissions, but the effect of instrument response time on concentration measurements is rarely considered. Furthermore, stable isotope ratios are increasingly used in mobile measurements to attribute sources, but the precision of mobile isotopic measurements depend on a combination of instrument and measurement conditions. Here we tested the effect of instrument speed on concentration measurements by outfitting a vehicle with isotopic and concentration-only gas analysers with different response times and conducting multiple mobile surveys. Additionally, we performed a sensitivity analysis for the isotopic precision achievable under different conditions by programming a physical model, validated with empirical data from our mobile surveys. We found that slower response time led to a greater underestimation of measured CH4 concentration, during both driving and stationary measurements, while the area under peaks in concentration is consistent and provides a robust means of comparing data between instruments. We also explore the use of an algorithm to improve instrument response. Our sensitivity analysis showed that the precision of isotopic measurements increases with the concentration range and the duration of the measurement following a power law. Our findings have important implications for the reporting and comparability of results between surveys with different instrumental setups and provide a framework for optimising sampling strategies under given objectives, conditions, and instrument capabilities.

Grassland fertilisation drives non-random plant loss resulting in areas dominated by perennial grass species. How these changes cascade through linked trophic levels, however, is not well understood. We studied how grassland fertilisation propagates change through the plant assemblage into the plant-flower-visitor, plant-leaf miner and leaf miner-parasitoid networks using a year's data collection from a long-term grassland fertiliser application experiment. Our experiment had three fertiliser treatments each applied to replicate plots 15 m(2) in size: mineral fertiliser, farmyard manure, and mineral fertiliser and farmyard manure combined, along with a control of no fertiliser. The combined treatment had the most significant impact, and both plant species richness and floral abundance decreased with the addition of fertiliser. While insect species richness was unaffected by fertiliser treatment, fertilised plots had a significantly higher abundance of leaf miners and parasitoids and a significantly lower abundance of bumblebees. The plant-flower-visitor and plant-herbivore networks showed higher values of vulnerability and lower modularity with fertiliser addition, while leaf miner-parasitoid networks showed a rise in generality. The different groups of insects were impacted by fertilisers to varying degrees: while the effect on abundance was the highest for leaf miners, the vulnerability and modularity of flower-visitor networks was the most affected. The impact on the abundance of leaf miners was positive and three times higher than the impact on parasitoids, and the impact on bumblebee abundance was negative and double the magnitude of impact on flower abundance. Overall, our results show that while insect species richness was unaffected by fertilisers, network structure changed significantly as the replacement of forbs by grasses resulted in changes in relative abundance across trophic levels, with the direction of change depending on the type of network. Synthesis. By studying multiple networks simultaneously, we were able to rank the relative impact of habitat change on the different groups of species within the community. This provided a more holistic picture of the impact of agricultural intensification and provides useful information when deciding on priorities for mitigation.

This dataset contains mobile isotopic (13C/12C) methane measurements and associated data collected around the Fylde, Lancaster, Morecambe Bay, and Barrow-in-Furness in North West England. Data were collected between November 2016 and March 2017.

This paper reviews recent developments in crop science that can be the basis of a revolution in the global food system but it is also emphasized that such a revolution requires more than changes in food production and supply. We must more effectively feed a growing global population with a healthy diet while also defining and delivering the kinds of sustainable food systems that will minimise damage to our planet. There are exciting new developments in crop production biology but much existing crop science can be exploited to increase yields with the aid of a knowledge exchange (KE) framework requiring the use of new technology now available to most people across the globe. We discuss novel approaches at both the plant and the crop level that will enhance nutrient and water productivity and we also outline ways in which energy use and greenhouse gas (GHG) emissions can be reduced and labor shortages combatted. Exploitation of new biology and new engineering opportunities will require development of public-private partnerships and collaborations across the disciplines to allow us to move effectively from discovery science to practical application. It is also important that consumers contribute to the debate over proposed changes to food and farming and so effective KE mechanisms are required between all relevant communities.

Climate warming affects plant physiology through genetic adaptation and phenotypic plasticity, but little is known about how these mechanisms influence ecosystem processes. We used three elevation gradients and a reciprocal transplant experiment to show that temperature causes genetic change in the sedge Eriophorum vaginatum. We demonstrate that plants originating from warmer climate produce fewer secondary compounds, grow faster and accelerate carbon dioxide (CO2 ) release to the atmosphere. However, warmer climate also caused plasticity in E. vaginatum, inhibiting nitrogen metabolism, photosynthesis and growth and slowing CO2 release into the atmosphere. Genetic differentiation and plasticity in E. vaginatum thus had opposing effects on CO2 fluxes, suggesting that warming over many generations may buffer, or reverse, the short-term influence of this species over carbon cycle processes. Our findings demonstrate the capacity for plant evolution to impact ecosystem processes, and reveal a further mechanism through which plants will shape ecosystem responses to climate change.

Evidence suggests that the restoration of plant diversity in grasslands not only brings benefits for biodiversity conservation, but also the delivery of ecosystem services. While biodiversity-function experiments show that greater plant diversity increases resistance of plant productivity to climate extremes, it is not known whether real-world management options for grassland restoration likewise stabilize ecosystem responses to extreme climate events. We used a long-term (23 year) field experiment in northern England to test the hypothesis that management aimed at biodiversity restoration increases the resistance and recovery of ecosystem carbon (C) fluxes to short-term summer drought. This was tested by measuring plant, soil and microbial responses to a simulated drought in experimental grassland plots where fertilizer application and seed addition have been managed to enhance plant species diversity. The cessation of fertilizer application brought about small increases in plant species richness. Additionally, cessation of fertilizer application reduced overall plant productivity and promoted hemi-parasitic plants at the expense of grasses and forbs. Resistance of CO2 fluxes to drought, measured as ecosystem respiration, was greater in non-fertilized plots, as lower plant biomass reduced water demand, likely aided by proportionally more hemi-parasitic plants further reducing plant biomass. Additionally, legumes increased under drought, thereby contributing to overall resistance of plant productivity. Recovery of soil microbial C and nitrogen was more rapid after rewetting than soil microbial community composition, irrespective of restoration treatment, suggesting high resilience of soil microbial communities to drought. Synthesis and applications. This study shows that while grassland diversity restoration management increases the resistance of carbon fluxes to drought, it also reduces agricultural yields, revealing a trade-off for land managers. Furthermore legumes, promoted through long-term restoration treatments, can help to maintain plant community productivity under drought by increasing their biomass. As such, grassland management strategies not only have consequences for ecosystem processes, but also the capacity to withstand extreme weather events.

Developing a holistic understanding of the ecosystem impacts of global change requires methods that can quantify the interactions among multiple response variables. One approach is to generate high dimensional spaces, or hypervolumes, to answer ecological questions in a multivariate context. A range of statistical methods has been applied to construct hypervolumes but have not yet been applied in the context of ecological data sets with spatial or temporal structure, for example, where the data are nested or demonstrate temporal autocorrelation. We outline an approach to account for data structure in quantifying hypervolumes based on the multivariate normal distribution by including random effects. Using simulated data, we show that failing to account for structure in data can lead to biased estimates of hypervolume properties in certain contexts. We then illustrate the utility of these "model-based hypervolumes" in providing new insights into a case study of afforestation effects on ecosystem properties where the data has a nested structure. We demonstrate that the model-based generalization allows hypervolumes to be applied to a wide range of ecological data sets and questions.

Carly J. Stevens, Beth F.T. Brockett, Catherine Baxendale, Ali J. Birkett, Caley Brown, Andrew J. Cole, Iain Gould, Hannah Griffiths, Richard Nicholson , Helen Quirk, Isabel Rogers, Tom N. Walker, Susan E. Ward Lancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK. Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK. Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, LA1 4AP, UK.

The importance of managing land to optimize carbon sequestration for climate change mitigation is widely recognized, with grasslands being identified as having the potential to sequester additional carbon. However, most soil carbon inventories only consider surface soils, and most large-scale surveys group ecosystems into broad habitats without considering management intensity. Consequently, little is known about the quantity of deep soil carbon and its sensitivity to management. From a nationwide survey of grassland soils to 1 m depth, we show that carbon in grassland soils is vulnerable to management and that these management effects can be detected to considerable depth down the soil profile, albeit at decreasing significance with depth. Carbon concentrations in soil decreased as management intensity increased, but greatest soil carbon stocks (accounting for bulk density differences), were at intermediate levels of management. Our study also highlights the considerable amounts of carbon in subsurface soil below 30 cm, which is missed by standard carbon inventories. We estimate grassland soil carbon in Great Britain to be 2097 Tg C to a depth of 1 m, with ~60% of this carbon being below 30 cm. Total stocks of soil carbon (t ha(-1) ) to 1 m depth were 10.7% greater at intermediate relative to intensive management, which equates to 10.1 t ha(-1) in surface soils (0-30 cm), and 13.7 t ha(-1) in soils from 30 to 100 cm depth. Our findings highlight the existence of substantial carbon stocks at depth in grassland soils that are sensitive to management. This is of high relevance globally, given the extent of land cover and large stocks of carbon held in temperate managed grasslands. Our findings have implications for the future management of grasslands for carbon storage and climate mitigation, and for global carbon models which do not currently account for changes in soil carbon to depth with management.

Northern peatlands have accumulated one third of the Earth's soil carbon stock since the last Ice Age. Rapid warming across northern biomes threatens to accelerate rates of peatland ecosystem respiration. Despite compensatory increases in net primary production, greater ecosystem respiration could signal the release of ancient, century‐ to millennia‐old carbon from the peatland organic matter stock. Warming has already been shown to promote ancient peatland carbon release, but, despite the key role of vegetation in carbon dynamics, little is known about how plants influence the source of peatland ecosystem respiration. Here, we address this issue using in situ 14 C measurements of ecosystem respiration on an established peatland warming and vegetation manipulation experiment. Results show that warming of approximately 1 °C promotes respiration of ancient peatland carbon (up to 2100 years old) when dwarf‐shrubs or graminoids are present, an effect not observed when only bryophytes are present. We demonstrate that warming likely promotes ancient peatland carbon release via its control over organic inputs from vascular plants. Our findings suggest that dwarf‐shrubs and graminoids prime microbial decomposition of previously ‘locked‐up’ organic matter from potentially deep in the peat profile, facilitating liberation of ancient carbon as CO 2 . Furthermore, such plant‐induced peat respiration could contribute up to 40% of ecosystem CO 2 emissions. If consistent across other subarctic and arctic ecosystems, this represents a considerable fraction of ecosystem respiration that is currently not acknowledged by global carbon cycle models. Ultimately, greater contribution of ancient carbon to ecosystem respiration may signal the loss of a previously stable peatland carbon pool, creating potential feedbacks to future climate change.

The ability to carry out systematic, accurate and repeatable vegetation surveys is an essential part of long-term scientific studies into ecosystem biodiversity and functioning. However, current widely used traditional survey techniques such as destructive harvests, pin frame quadrats and visual cover estimates can be very time consuming and are prone to subjective variations. We investigated the use of digital image techniques as an alternative way of recording vegetation cover to plant functional type level on a peatland ecosystem. Using an established plant manipulation experimental site at Moor House NNR (an Environmental Change Network site), we compared visual cover estimates of peatland vegetation with cover estimates using digital image classification methods, from 0.5m×0.5m field plots. Our results show that digital image classification of photographs taken with a standard digital camera can be used successfully to estimate dwarf-shrub and graminoid vegetation cover at a comparable level to field visual cover estimates, although the methods were less effective for lower plants such as mosses and lichens. Our study illustrates the novel application of digital image techniques to provide a new way of measuring and monitoring peatland vegetation to the plant functional group level, which is less vulnerable to surveyor bias than are visual field surveys. Furthermore, as such digital techniques are highly repeatable, we suggest that they have potential for use in long-term monitoring studies, at both plot and landscape scales.

There is growing recognition that changes in vegetation composition can strongly influence peatland carbon cycling, with potential feedbacks to future climate. Nevertheless, despite accelerated climate and vegetation change in this ecosystem, the growth responses of peatland plant species to combined warming and vegetation change are unknown. Here, we used a field warming and vegetation removal experiment to test the hypothesis that dominant species from the three plant functional types present (dwarf-shrubs: Calluna vulgaris; graminoids: Eriophorum vaginatum; bryophytes: Sphagnum capillifolium) contrast in their growth responses to warming and the presence or absence of other plant functional types. Warming was accomplished using open top chambers, which raised air temperature by approximately 0.35 °C, and we measured air and soil microclimate as potential mechanisms through which both experimental factors could influence growth. We found that only Calluna growth increased with experimental warming (by 20%), whereas the presence of dwarf-shrubs and bryophytes increased growth of Sphagnum (46%) and Eriophorum (20%), respectively. Sphagnum growth was also negatively related to soil temperature, which was lower when dwarf-shrubs were present. Dwarf-shrubs may therefore promote Sphagnum growth by cooling the peat surface. Conversely, the effect of bryophyte presence on Eriophorum growth was not related to any change in microclimate, suggesting other factors play a role. In conclusion, our findings reveal contrasting abiotic and biotic controls over dominant peatland plant growth, suggesting that community composition and carbon cycling could be modified by simultaneous climate and vegetation change.

Historically, slow decomposition rates have resulted in the accumulation of large amounts of carbon in northern peatlands. Both climate warming and vegetation change can alter rates of decomposition, and hence affect rates of atmospheric CO 2 exchange, with consequences for climate change feedbacks. Although warming and vegetation change are happening concurrently, little is known about their relative and interactive effects on decomposition processes. To test the effects of warming and vegetation change on decomposition rates, we placed litter of three dominant species ( Calluna vulgaris , Eriophorum vaginatum , Hypnum jutlandicum ) into a peatland field experiment that combined warming with plant functional group removals, and measured mass loss over two years. To identify potential mechanisms behind effects, we also measured nutrient cycling and soil biota. We found that plant functional group removals exerted a stronger control over short‐term litter decomposition than did ~1°C warming, and that the plant removal effect depended on litter species identity. Specifically, rates of litter decomposition were faster when shrubs were removed from the plant community, and these effects were strongest for graminoid and bryophyte litter. Plant functional group removals also had strong effects on soil biota and nutrient cycling associated with decomposition, whereby shrub removal had cascading effects on soil fungal community composition, increased enchytraeid abundance, and increased rates of N mineralization. Our findings demonstrate that, in addition to litter quality, changes in vegetation composition play a significant role in regulating short‐term litter decomposition and belowground communities in peatland, and that these impacts can be greater than moderate warming effects. Our findings, albeit from a relatively short‐term study, highlight the need to consider both vegetation change and its impacts below ground alongside climatic effects when predicting future decomposition rates and carbon storage in peatlands.