Search

The Flow Country blanket bogs in the counties of Caithness and Sutherland (northern Scotland, UK) harbour internationally important populations of specialist open-bog breeding bird species. However, commercial afforestation carried out in the 1980s, involving the non-native tree species lodgepole pine (Pinus contorta) and sitka spruce (Picea sitchensis) covering over 67,000 hectares (ca. 17 %) of the peatland, has significantly affected bird assemblages within and around the plantations. We conducted a literature review to identify the avian winners and losers resulting from this transformation. Our synthesis of existing findings confirms that afforestation has led to changes in the availability of breeding and foraging habitat, alterations in inter- and intra-specific competition dynamics, and the creation of forest edge effects. Crucially, the open-bog bird assemblages have been largely replaced by woodland specialists and generalists. While 33 species (including five Red-listed Birds of Conservation Concern) are observed to benefit from afforestation, these gains are arguably of lower conservation value than the original open-bog assemblages (27 species including 11 Red-listed species). As a mean proportion of the British population range, the Flow Country has a significantly higher proportion of Amber and Green-listed loser species than winners. Understanding the changes in assemblages is crucial for informing future decisions regarding forest planting and re-planting, particularly in the context of the ongoing dual challenges of climate change and biodiversity loss. Further research is necessary to comprehend the effects of afforestation on populations of waterfowl associated with open water features present in the blanket bog landscape. Given the need for woodland creation, bird conservation would benefit from leaving naturally open habitats intact and siting new woodland in areas that were formerly naturally forested.

Understanding hydrological processes operating on relatively intact blanket bogs provides a scientific basis for establishing achievable restoration targets for damaged sites. A GIS-based hydrological model, developed to assess restoration potential of Irish raised bogs, was adapted and applied to four relatively intact blanket bogs in Ireland. The Modified Flow Accumulation Capacity (MFAC) model utilised high-resolution topographic data to predict surface wetness, based on climatic conditions, contributing catchment and local surface slope. Modifications to MFAC parameters aimed to account for differences in hydrological processes between raised bogs and blanket bogs. Application of a climatic correction factor accounted for variations in effective rainfall between the four study sites, while monitoring of water table levels indicated a log-linear relationship between MFAC values and summer water table levels and range of water table fluctuations. Deviations from the observed relationship between MFAC and water table levels were associated with hydrological pressures, such as artificial drainage or the occurrence of subsurface macropores (peat pipes), which further lowered summer water tables. Despite being effective as a predictor of relative surface wetness, the relationship between MFAC and ecological variables such as Sphagnum spp. cover proved poor, pointing to the impact of past activities and damage caused by anthropogenic pressures. Findings demonstrated MFAC as an effective tool in predicting surface wetness within blanket bog-covered landscapes, thus proving useful to peatland practitioners in planning and prioritising areas for restoration. [ABSTRACT FROM AUTHOR]

Species distribution models (SDMs) have been widely used to predict species ranges and their future distribution under climate change scenarios, mostly using only climatic variables. An important factor that is usually neglected, is the habitat of the species that are being modelled. Even when included, it is often considered a fixed factor, but in reality, it is also subjected to changes. In this study, we assessed if this omission can lead to different projected distributions of the species. For this purpose, we applied an ensemble of SDMs, and we projected the distribution of rare bryophyte species in Scotland in the 2050s. Bryophytes are generally very climate-reliant and lend themselves to bioclimatic studies, and we selected species different grades of affinity with blanket bogs, which are threatened by climate change. Blanket bog extension was included in the model as an explanatory variable, and the models were run for three 2050s scenarios: once with the current blanket bog distribution and twice using the blanket bog distribution derived from two bioclimatic models (Lindsay modified and Blanket Bog Tree model), under the same climate change projections. The results showed some differences in the predicted future distribution of those species with a strong relationship with blanket bogs, when habitat changes were accounted for. For example, Sphagnum majus, the species with the highest affinity with blanket bog in our study, was not predicted to change its future distribution when blanket bog is held constant at the current level, but was predicted to lose up to 60% of its current suitable area when the projected loss of blanket bog is included. Our results suggest that adding future habitat changes could improve the reliability of SDMs in the first steps of planning for conservation and restoration. [ABSTRACT FROM AUTHOR]

Peatlands are a vast global carbon store. Both climate change and management have shaped peatlands over millennia, sometimes negatively, sometimes positively. Across the globe, prescribed fire is an important and well-recognised vegetation management tool used to promote biodiversity, increase habitat heterogeneity and mitigate uncontrolled wildfires. However, in the UK, there is an ongoing debate about the efficacy and legitimacy of using prescribed fire as a vegetation management tool. The debate centres around the extent to which prescribed burning is associated with a decline in habitat status and ecological function, especially in relation to carbon storage within heather-dominated blanket bog peatlands. Robust reviews of the evidence base are thus required to disentangle this debate and inform land management policies that ensure the protection and enhancement of blanket bog ecological functioning. Here, we critically review "Carbon storage and sequestration by habitat: a review of the evidence (second edition)" by Gregg et al., 2021. We see the value in synthesising the evidence on this topic but question the methodological approach used by Gregg et al. Another concern is their misrepresentation of evidence relating to prescribed burning impacts on blanket bog ecosystems and carbon budgets. We highlight these issues by focusing on the relevant peatland sections within the review by Gregg et al. and conclude by making a series of recommendations to improve the review's scientific robustness and, thereby, its value to academics, land managers and policymakers. [ABSTRACT FROM AUTHOR]

Bog asphodel, Narthecium ossifragum, is a flowering plant, commonly found in many wet acidic habitats, including upland blanket bogs where sheep and cattle grazing has been considered as the most feasible economic activity. It can be fatally toxic, especially to lambs, so there is concern that re-establishing blanket bog habitat will increase the distribution and abundance of bog asphodel and thus further threaten the marginal livelihoods of upland livestock farmers. Analysis of vegetation survey data collected pre- and post-restoration from 43 restored shallow peatland sites on Exmoor, an upland area on the northern coast of the UK’s southwestern peninsula, showed only a small (4 %) increase in spatial distribution following restoration (rewetting). No increase in bog asphodel abundance was seen at six sites for which pre- and post-restoration percentage cover data were available. Moreover, bog asphodel did not appear post-restoration at any of the 21 sites (48 %) where it had not been recorded pre-restoration. A separate detailed study at one site demonstrated typical bog asphodel phenology and a life history strategy of growing and reproducing very slowly but persisting despite cold, wet and acidic conditions. Therefore, bog asphodel is ecologically unlikely to respond within a decade to any major change in its environment, such as rewetting of the peat. However, bog asphodel on Exmoor does show significant variability in size and in the proportion of plants that flower year on year. While the mechanisms by which bog asphodel exerts its toxic effect when ingested by ruminants have yet to be fully elucidated, the inconsistent pattern of toxicity seen in other parts of the UK and in northern Europe, where bog asphodel poisoning is reported to be a serious economic problem, may be driven by the influence of environmental factors on bog asphodel growth.

Wildfires are an increasing concern due to rising temperatures and incidence of droughts associated with changing climate, poor land management, and direct human interference. Most studies of the impact of fire on temperate heathland and bog examined the consequences of controlled or prescribed burning. Less is known about the impacts of uncontrolled wildfires on sites designated for their conservation value. We examined the initial impact and short‐term trajectory (3.5 years) of cool temperate peatland plant and arthropod communities on designated upland sites in Northern Ireland following wildfires, that is, unplanned with respect to where and when they occur, severity, and duration. These near simultaneous wildfires were often due to a failure to control prescribed burns. Wildfires were associated with a loss of blanket bog and heath indicator species. Broad vegetation groups showed initial recovery characterized by a decrease in bare ground and increasing cover of shrub species and bryophytes. However, at a species level, Sphagnum spp and bryophyte communities, which are central to peatland ecosystem functioning, showed no sign of recovery to prefire composition. Rather, bryophyte communities became more divergent over the course of the study and were mainly characterized by increased abundance of the alien pioneer acrocarp Campylopus introflexus. Similarly, composition of arthropod communities (ground beetles and spiders) differed between burnt and unburnt areas and showed no evidence of a return to species composition in unburnt areas. The nationally rare beetle Carabus nitens was more common in the aftermath of wildfire. Synthesis. Whilst, long‐term recovery was not investigated, these short‐term changes suggest enduring detrimental impacts on the distinctive communities associated with peatlands, primarily through the loss of Sphagnum spp., affecting ecosystem services such as carbon sequestration and water and soil retention. It may not be possible to restore exact prefire species composition of plant and animal communities. We suggest a precautionary approach involving management of upland vegetation, public education, and vigilance, to prevent further wildfires and protect these key upland habitats. [ABSTRACT FROM AUTHOR]

Abstract Wildfires are an increasing concern due to rising temperatures and incidence of droughts associated with changing climate, poor land management, and direct human interference. Most studies of the impact of fire on temperate heathland and bog examined the consequences of controlled or prescribed burning. Less is known about the impacts of uncontrolled wildfires on sites designated for their conservation value. We examined the initial impact and short‐term trajectory (3.5 years) of cool temperate peatland plant and arthropod communities on designated upland sites in Northern Ireland following wildfires, that is, unplanned with respect to where and when they occur, severity, and duration. These near simultaneous wildfires were often due to a failure to control prescribed burns. Wildfires were associated with a loss of blanket bog and heath indicator species. Broad vegetation groups showed initial recovery characterized by a decrease in bare ground and increasing cover of shrub species and bryophytes. However, at a species level, Sphagnum spp and bryophyte communities, which are central to peatland ecosystem functioning, showed no sign of recovery to prefire composition. Rather, bryophyte communities became more divergent over the course of the study and were mainly characterized by increased abundance of the alien pioneer acrocarp Campylopus introflexus. Similarly, composition of arthropod communities (ground beetles and spiders) differed between burnt and unburnt areas and showed no evidence of a return to species composition in unburnt areas. The nationally rare beetle Carabus nitens was more common in the aftermath of wildfire. Synthesis. Whilst, long‐term recovery was not investigated, these short‐term changes suggest enduring detrimental impacts on the distinctive communities associated with peatlands, primarily through the loss of Sphagnum spp., affecting ecosystem services such as carbon sequestration and water and soil retention. It may not be possible to restore exact prefire species composition of plant and animal communities. We suggest a precautionary approach involving management of upland vegetation, public education, and vigilance, to prevent further wildfires and protect these key upland habitats.

The present study assessed the IUCN categories of 27 taxa belonging to genus Sphagnum from Turkey. Result of this evaluation showed that two taxa, S. flexuosum and S. fimbriatum are Critically Endangered; 5 taxa, S. angutifolium, S. fuscum, S. rubellum, S. squarrosum and S. warnstorfii, are vulnerable; and 6 taxa, S.contortum, S. medium, S. quinquefarium, S. papillosum, S. subfulvum and S. tenellum, are endangered. Moreover, 4 taxa were assessed as Near Threatened and 9 taxa were assessed as Least Concern. Lastly, S. cuspidatum which has been reported recently from Turkey was evaluated as data deficient. At the end of study, it has been determined that habitat losses are the most important threatening factor and conservation strategies are proposed for each species. [ABSTRACT FROM AUTHOR]

The net impact of greenhouse gas emissions from degraded peatland environments on national Inventories and subsequent mitigation of such emissions has only been seriously considered within the last decade. Data on greenhouse gas emissions from special cases of peatland degradation, such as eroding peatlands, are particularly scarce. Here, we report the first eddy covariance-based monitoring of carbon dioxide (CO2) emissions from an eroding Atlantic blanket bog. The CO2 budget across the period July 2018–November 2019 was 147 (± 9) g C m−2. For an annual budget that contained proportionally more of the extreme 2018 drought and heat wave, cumulative CO2 emissions were nearly double (191 g C m−2) of that of an annual period without drought (106 g C m−2), suggesting that direct CO2 emissions from eroded peatlands are at risk of increasing with projected changes in temperatures and precipitation due to global climate change. The results of this study are consistent with chamber-based and modelling studies that suggest degraded blanket bogs to be a net source of CO2 to the atmosphere, and provide baseline data against which to assess future peatland restoration efforts in this region. [ABSTRACT FROM AUTHOR]

The upland and mountainous regions of northern Europe provide a wide variety of ecosystem services. However, these ecosystem services are highly vulnerable to environmental and land-use change. To ensure their future conservation, it is therefore, essential to understand whether upland plant communities will respond positively or negatively to a range of environmental factors such as grazing pressure and landscape-scale factors such as changes in atmospheric SO2 and NOx deposition. To understand this, here, we describe the long-term trends in four UK upland communities (high-level grassland, intermediate grassland, blanket bog, high-level bog) using four replicated long-term experiments examining the effects of sheep grazing compared to no-sheep grazing in Moor House (from 1954 to 2016). Our results showed that species richness and abundance recovered in grazed plots after 2000, with improvements in species richness and abundance of vascular plants, mosses, and liverworts. Unfortunately, no improvement was found for lichens. Species richness, vascular plants, and mosses recovered the fastest, and much faster than liverworts. There was no evidence of slower recovery of species richness and abundance in plots where sheep grazing was removed. These results are consistent with longitudinal studies suggesting recovery after 2000 as a result of reduced atmospheric deposition. Although trends in diversity and abundance in the grazed and ungrazed plots were not identical, they were not markedly different either. The similar richness and abundance trends in the grazed and ungrazed plots found in each plant community suggest that within-community dynamics may overcome initial differences between the grazing treatments over time. In contrast, differences in richness and abundance among plant communities over time suggest that some landscape-scale trends, such as those caused by a reduction in nutrient inputs, initiate community-dependent recovery.

Peatlands are a vast global carbon store. Both climate change and management have shaped peatlands over millennia, sometimes negatively, sometimes positively. Across the globe, prescribed fire is an important and well-recognised vegetation management tool used to promote biodiversity, increase habitat heterogeneity and mitigate uncontrolled wildfires. However, in the UK, there is an ongoing debate about the efficacy and legitimacy of using prescribed fire as a vegetation management tool. The debate centres around the extent to which prescribed burning is associated with a decline in habitat status and ecological function, especially in relation to carbon storage within heather-dominated blanket bog peatlands. Robust reviews of the evidence base are thus required to disentangle this debate and inform land management policies that ensure the protection and enhancement of blanket bog ecological functioning. Here, we critically review “Carbon storage and sequestration by habitat: a review of the evidence (second edition)” by Gregg et al., 2021. We see the value in synthesising the evidence on this topic but question the methodological approach used by Gregg et al. Another concern is their misrepresentation of evidence relating to prescribed burning impacts on blanket bog ecosystems and carbon budgets. We highlight these issues by focusing on the relevant peatland sections within the review by Gregg et al. and conclude by making a series of recommendations to improve the review’s scientific robustness and, thereby, its value to academics, land managers and policymakers.

Harvesting of plantation conifers on peatlands is carried out as part of restoration and forestry operations. In particular, in the UK and Ireland, conifer plantations on drained ombrotrophic blanket and raised bogs are increasingly being removed (by harvesting), along with blocking of drainage ditches to help raise water tables to reinitiate and restore bog vegetation and function. However, both tree harvesting and peatland restoration operations can have significant impacts on water quality at local and catchment scales. Previous research has suggested that leaching from leftover decomposing brash (tree tops and branches, including wood and needles) is the primary cause, while other work has suggested that release from rewetted peat also contributes to water quality changes. This research investigates the relative importance of peat rewetting, needles and branches on water quality using mesocosm experiments, to help elucidate the mechanisms behind water quality changes following restoration and harvesting operations. Peat and brash were collected from a drained afforested blanket bog in the Flow Country, Scotland. Short-term mesocosm experiments were conducted by incubating peat, peat + needles and peat + needles + branches with rainwater in quadruplicate. Brash from Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus contorta) was investigated separately, while we also conducted experiments with fresh and aged (∼18 months) brash. Peat, needles and branches all significantly impacted water quality in the order of branches > needles > peat, while concentrations of DOC, PO 4 3−, NH 4 +, K and Mn were most impacted. Water quality impacts of spruce brash appeared generally greater than pine, while fresh brash had larger effects than aged brash. In our mesocosms, relative contributions to water quality changes were estimated by elemental yields. On average, peat contributed 25.4% (range 0.6–72.3%), while needles and brash contributed 19.7% (range 3.0–37.0%) and 54.9% (range 22.1–70.2%) to yields, respectively. We further estimate that 267 kg C ha−1 (255.8 kg as DOC, 10.7 kg as DIC), 27.4 kg K ha−1, 5.8 kg P ha−1 (as PO 4 3−) and 0.5 kg N ha−1 (as NH 4 +) could be released from brash, over nine days. [Display omitted] • Relative contributions of peat, needles and branches to water quality were assessed. • DOC, PO 4 3−, NH 4 +, K and Mn were collectively the variables most impacted. • Contributions to leaching were peat (25.4%), needles (19.7%) and branches (54.0%). • Removal of needles and branches could help mitigate water pollution. [ABSTRACT FROM AUTHOR]

Over the last 20 years, ecological restoration of degraded habitats has become common in conservation practice. Mountain hares (Lepus timidus scoticus) were surveyed during 2017–2021 using 830 km of line transects in the Peak District National Park, England. Historically degraded bog areas were previously reported having low hare numbers. Following bog restoration, we found hare densities of 32.6 individuals km−2, notably higher than neighboring degraded (unrestored) bog with 24.4 hares km−2. Hare density on restored peatland was 2.7 times higher than on bogs managed for grouse shooting at 12.2 hares km−2 and 3.3 times higher than on heather moorland managed for grouse shooting at 10.0 hares km−2. Yearly estimates varied most on habitats managed for grouse, perhaps indicative of the impact of habitat management, for example, heather burning and/or possible hare culling to control potential tick‐borne louping ill virus in gamebirds. Acid grassland used for sheep farming had a similar density to grouse moorland at 11.8 hares km−2. Unmanaged dwarf shrub heath had the lowest density at 4.8 hares km−2. Hare populations are characterized by significant yearly fluctuations, those in the study area increasing by 60% between 2017 and 2018 before declining by ca. 15% by 2020 and remaining stable to 2021. During an earlier survey in 2002, total abundance throughout the Peak District National Park was estimated at 3361 (95% CI: 2431–4612) hares. The present study estimated 3562 (2291–5624) hares suggesting a stable population over the last two decades despite fluctuations likely influenced by weather and anthropogenic factors. Mountain hares in the Peak District favored bog habitats and were associated with restored peatland habitat. Wildlife management should be cognizant of hare density variation between habitats, which may have implications for local extinction risk. [ABSTRACT FROM AUTHOR]

The responses of peatland invertebrates to land use changes and associated effects of peatland degradation are not well known, particularly for diverse and species-rich taxa such as moths. We investigated broad patterns of distribution in moth communities during the restoration of formerly afforested blanket bog, as well as their degree of habitat affinity (tyrphophilia). Thus, we examined the response of moth communities to peatland management across a restoration chronosequence and used information about species traits to explain the species’ responses to restoration (trait syndromes). A clear shift towards open habitat moth species and away from specialist forest species took place following tree felling, and the moth communities of restoration treatments resembled the bog community within a few years following onset of restoration. Interestingly, species traditionally considered tyrphobionts (bog specialists) were not restricted to core bog habitats. Trait syndromes were identified for each treatment, highlighting the importance of phylogenetic, phenological and ecological performance traits linked mainly to species microhabitat selection, resource use and dispersal capability. The restoration of afforested blanket bog opens up the habitat for the recolonisation of bog-inhabiting moth species, mediated by species functional traits. However, a better understanding of moth functional traits, especially linked to moth ecology (including habitat preferences), is needed to aid understanding of the relationship between restoration trajectory, species traits and blanket bog habitat.

Abstract Over the last 20 years, ecological restoration of degraded habitats has become common in conservation practice. Mountain hares (Lepus timidus scoticus) were surveyed during 2017–2021 using 830 km of line transects in the Peak District National Park, England. Historically degraded bog areas were previously reported having low hare numbers. Following bog restoration, we found hare densities of 32.6 individuals km−2, notably higher than neighboring degraded (unrestored) bog with 24.4 hares km−2. Hare density on restored peatland was 2.7 times higher than on bogs managed for grouse shooting at 12.2 hares km−2 and 3.3 times higher than on heather moorland managed for grouse shooting at 10.0 hares km−2. Yearly estimates varied most on habitats managed for grouse, perhaps indicative of the impact of habitat management, for example, heather burning and/or possible hare culling to control potential tick‐borne louping ill virus in gamebirds. Acid grassland used for sheep farming had a similar density to grouse moorland at 11.8 hares km−2. Unmanaged dwarf shrub heath had the lowest density at 4.8 hares km−2. Hare populations are characterized by significant yearly fluctuations, those in the study area increasing by 60% between 2017 and 2018 before declining by ca. 15% by 2020 and remaining stable to 2021. During an earlier survey in 2002, total abundance throughout the Peak District National Park was estimated at 3361 (95% CI: 2431–4612) hares. The present study estimated 3562 (2291–5624) hares suggesting a stable population over the last two decades despite fluctuations likely influenced by weather and anthropogenic factors. Mountain hares in the Peak District favored bog habitats and were associated with restored peatland habitat. Wildlife management should be cognizant of hare density variation between habitats, which may have implications for local extinction risk.

A lack of information concerning the hydrology and hydrogeology of intact blanket bogs limits current understanding of how their alteration to mature forestry plantations impacts stream flow and associated water quality. An integrated hydrological/hydrogeological monitoring programme compared processes operating in a relatively intact blanket peat‐covered catchment with conditions encountered in an adjacent area under closed canopy plantation forestry. Groundwater monitoring revealed contrasting water level regimes and deeper summer water tables in the afforested area, with forest groundwater also having more elevated specific electrical conductance (SEC) and containing higher concentrations of dissolved organic carbon (DOC). Near‐simultaneous pairwise runoff sampling at the relatively intact catchment and afforested catchment outlets demonstrated no significant difference in DOC concentration. Conversely, water samples from the afforested catchment outlet displayed significantly greater SEC; this arose in part because of higher concentrations of dissolved calcium and magnesium, discharging via artificial drainage. Comparison of base flow runoff SEC with peat groundwater samples reflected in significant contrasts in ionic signature and greater levels of mineralisation in surface water, pointing to contributions of deeper water, derived from inorganic substrate materials. Study findings indicate that disturbance to the ground in that part of the catchment under plantation forestry has led to greater variations in stream flow and water quality for aquatic ecosystems. Comparable conditions have been observed instreams flowing through plantation forestry in similar physical settings elsewhere. Study findings suggest that plantations on deep peat can adversely affect stream ecosystems and this may impact on a water body's legal status. [ABSTRACT FROM AUTHOR]

Bog asphodel, Narthecium ossifragum, is a flowering plant, commonly found in many wet acidic habitats, including upland blanket bogs where sheep and cattle grazing has been considered as the most feasible economic activity. It can be fatally toxic, especially to lambs, so there is concern that re-establishing blanket bog habitat will increase the distribution and abundance of bog asphodel and thus further threaten the marginal livelihoods of upland livestock farmers. (1) Analysis of vegetation survey data collected pre- and post-restoration from 43 restored shallow peatland sites on Exmoor, an upland area on the northern coast of the UK's southwestern peninsula, showed only a small (4 %) increase in spatial distribution following restoration (rewetting). No increase in bog asphodel abundance was seen at six sites for which pre- and post-restoration percentage cover data were available. Moreover, bog asphodel did not appear post-restoration at any of the 21 sites (48 %) where it had not been recorded pre-restoration. (2) A separate detailed study at one site demonstrated typical bog asphodel phenology and a life history strategy of growing and reproducing very slowly but persisting despite cold, wet and acidic conditions. Therefore, bog asphodel is ecologically unlikely to respond within a decade to any major change in its environment, such as rewetting of the peat. However, bog asphodel on Exmoor does show significant variability in size and in the proportion of plants that flower year on year. (3) While the mechanisms by which bog asphodel exerts its toxic effect when ingested by ruminants have yet to be fully elucidated, the inconsistent pattern of toxicity seen in other parts of the UK and in northern Europe, where bog asphodel poisoning is reported to be a serious economic problem, may be driven by the influence of environmental factors on bog asphodel growth. [ABSTRACT FROM AUTHOR]

Question: Northern peatlands are increasingly threatened by wildfire. Severe peatland wildfires can provide opportunities for new non‐peatland species to colonise post fire. Changes in plant colonisation could lead to longer‐term shifts in community composition, compromising recovery of peatland structure and function. Understanding the process of post‐fire recovery can thus inform restoration action and help restore peatland vascular plant communities. In this study, we ask: what drives initial vascular plant recovery following a peatland wildfire? Location: Stalybridge moors, England (commonly referred to as the Saddleworth moors). Methods: We used a series of vegetation surveys and seed germination experiments to identify the composition of vascular plant community one‐year post fire, along with potential propagule sources. We combined this with plant trait data and, using a series of null models, compared observed community trait values against random species assemblages. Results: Our data suggests that plant species are able to arrive at the burned site through multiple non‐exclusive recolonisation pathways. This includes colonisation through the soil seed bank, along with dispersal from surrounding unburned peatland and non‐peatland vegetation. The composition and structure of the recolonised communities was largely determined by the ability of species to reach the post‐fire site from these donor communities. This resulted in a post‐fire community composed of species possessing lower seed masses relative to the wider pool of potential colonisers. Conclusions: Our results highlight propagule availability as a driver of post‐wildfire vascular plant recovery. This provides opportunities for new non‐peatland species to colonise, potentially driving changes in the direction of vegetation recovery. Ensuring the availability of peatland species following a wildfire could therefore be key to the immediate recovery of these systems. [ABSTRACT FROM AUTHOR]

Despite substantial contrary evidence, there has been a growing tendency to present prescribed vegetation burning as a management practice that is always damaging to peatland ecosystems in the UK. This is exemplified by the “Burning and Peatlands” position statement published by the International Union for Conservation of Nature UK Peatland Programme. Indeed, while we strongly agree with several of the statements made within this position statement, it also contains a series of unverified assertions and misleading arguments that seemingly serve to simplify the narrative and paint prescribed burning as a wholly damaging peatland management tool. Given that this position statement is published by one of the UK’s most prominent peatland conservation organisations, it is likely to be consulted when debating upland land use policy. Therefore, for the benefit of policymakers, we provide a point-by-point critical review of the “Burning and Peatlands” position statement. We also discuss several further points for researchers and policymakers to consider that are consistently ignored by those attempting to simplify the narrative about prescribed burning. Our aim in producing this discussion paper is to encourage the research and policy community to move towards an evidence-based position about prescribed burning impacts on UK peatlands. [ABSTRACT FROM AUTHOR]

(1) Molinia caerulea occurs in peatland vegetation communities. However, under certain environmental and management conditions it may overwhelm the typical peatland vegetation, compromising ecosystem services including carbon dioxide (CO2) sequestration and storage. Improved understanding of the effects of M. caerulea on CO2 fluxes in peatland ecosystems will better inform landscape management. (2) Photosynthesis at a PPFD of 600 μmol m 2 s-1 (PG600), ecosystem respiration and partitioned (heterotrophic and autotrophic) below-ground respiration were calculated from closed-chamber measurements collected over the 2012–2014 growing seasons within two drained M. caerulea dominated peatland catchments in Exmoor National Park, southwest England. (3) All CO2 fluxes peaked in mid-summer, in association with increased soil temperature and vegetation growth. During wetter periods, below-ground autotrophic respiration and PG600 significantly decreased (p = 0.028 and p = 0.002), conversely heterotrophic respiration increased insignificantly (p = 0.081). An empirically derived net ecosystem exchange model estimated the growing season of 2012 to have been a smaller CO2 sink in carbon equivalents ( 126 ± 243 g m 2) than subsequent growing seasons ( 146 ± 310 and 234 ± 325 g m-2) due to lower photosynthetic rates during a cool, wet summer (2012). (4) Management aimed at preserving the carbon store and increasing carbon sequestration through raising water tables may reduce photosynthesis and increase heterotrophic respiration unless the dominance of M. caerulea is reduced and Sphagnum spp. cover increased.

The aim of this study was to investigate the controls on carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) dynamics on a blanket bog (at Pollagoona) and a raised bog (at Scohaboy) in Ireland after felling of plantation forestry and rewetting, and to produce annual balances for each gas at both sites. Gas fluxes were measured during a twelve-month period using the chamber method. Microsite types reflecting the dominant plant species at the chamber plots were identified and classified as Eriophorum-Sphagnum, Cladonia-Calluna and Molinia at Pollagoona and Eriophorum-Sphagnum, Cladonia-mosses, Eriophorum and brash (logging residues) at Scohaboy. The relationships between gas fluxes and environmental variables were assessed, and regression models were used to estimate annual CO2 and CH4 gas balances for each microsite type. Annual estimates of N2O exchange were calculated using seasonal means. Over the course of the study both sites acted as CO2 and CH4 sources. Although Pollagoona was an overall net source of CO2-C (131.6 ± 298.3 g m-2 yr-1), one microsite type (Cladonia-Calluna) acted as a strong sink for CO2-C (-142.8 g m-2 yr-1). Molinia microsites exhibited the highest CH4-C emissions (2.53 ± 1.01 g m-2 yr-1). Nitrous oxide emissions at Pollagoona were calculated as 12 μg m-2 yr-1. Scohaboy acted as a large CO2-C source (585.3 ± 241.5 g m-2 yr 1) (all microsite types) despite re-vegetation of non-brash plots, due to the availability of fresh organic matter across the site. Scohaboy was also a CH4-C source, emitting 3.25 ± 0.58 g m-2 yr-1. Emissions of both CO2-C (819.31 ± 57.7 g m-2 yr-1) and CH4-C (4.76 ± 0.98 g m-2 yr-1) were highest from the brash plots. Annual N2O-N emissions were small over the study period (72 µg m-2 yr-1). Our results indicate that, despite remedial work being conducted on both peatlands to raise the water table, the C sink function has not yet been restored at either site.

Peatlands are globally important ecosystems but many are degraded and some are eroding. However, some degraded peatlands are undergoing apparently spontaneous recovery, with switches from erosion to renewed carbon accumulation—a type of ecological regime shift.We used a palaeoecological approach to investigate and help understand such a switch in a blanket peatland in North Wales, UK.Our data show: (a) a rapid accumulation of new peat after the switch from the eroding state, with between 5.2 and 10.6 kg/m2 carbon accumulating since the beginning of the recovery which occurred between the late 1800s and early to mid‐1900s CE, with an average carbon accumulation rate in the new peat between 46 and 121 g C m−2 year−1; (b) three main successional pathways in peat‐forming vegetation and (c) hydrological changes with an increase to moderately high water‐tables after the switch that promoted new carbon accumulation as well as protecting vulnerable old carbon. External factors, including changes in climate and industrial activity, can only partially explain our results. Following previous studies, we suggest that internal ecosystem processes offer a substantial part of the explanation and interpret the switch to renewed carbon accumulation as a bifurcation‐type tipping point involving changes in the physical form of the eroded landscape.Synthesis. Our long‐term ecological data reveal a switch from a degraded peatland with active erosion and loss of carbon to a revegetated, wetter peatland accumulating carbon. The switch can be interpreted as a bifurcation tipping point. We suggest that external factors such as climate and pollution levels are important for setting suitable boundary conditions for peatland recovery, but internal mechanisms can explain the change in peatland state. Our study is the first of its kind to apply tipping point theory to the internal mechanisms linked to peat erosion and recovery and may help improve understanding of the trajectories of other peatlands in a changing climate. [ABSTRACT FROM AUTHOR]

Small mammals, such as small rodents (Rodentia: Muroidea) and shrews (Insectivora: Soricidae), present particular challenges in camera trap surveys. Their size is often insufficient to trigger infra-red sensors, whilst resultant images may be of inadequate quality for species identification. The conventional survey method for small mammals, live-trapping, can be both labour-intensive and detrimental to animal welfare. Here, we describe a method for using camera traps for monitoring small mammals. We show that by attaching the camera trap to a baited tunnel, fixing a close-focus lens over the camera trap lens, and reducing the flash intensity, pictures or videos can be obtained of sufficient quality for identifying species. We demonstrate the use of the method by comparing occurrences of small mammals in a peatland landscape containing (i) plantation forestry (planted on drained former blanket bog), (ii) ex-forestry areas undergoing bog restoration, and (iii) unmodified blanket bog habitat. Rodents were detected only in forestry and restoration areas, whilst shrews were detected across all habitat. The odds of detecting small mammals were 7.6 times higher on camera traps set in plantation forestry than in unmodified bog, and 3.7 times higher on camera traps in restoration areas than in bog. When absolute abundance estimates are not required, and camera traps are available, this technique provides a low-cost survey method that is labour-efficient and has minimal animal welfare implications. [ABSTRACT FROM AUTHOR]

Peatland erosion has important implications for ecosystem services such as carbon storage and biodiversity conservation. The extensive blanket bogs of Scotland’s Flow Country include some of the least damaged peatlands in the UK; nevertheless, erosion features occur widely in the area. Here we describe a high-altitude (340–440 m) heavily eroded peatland at Knockfin Heights in the Flow Country. The causes of this erosion are poorly understood, and could include both human and natural factors. Restoration management has been considered for the site, although this might be unnecessary if spontaneous recovery is taking place. Our study aimed to contribute to understanding whether recovery was occurring, by (i) accurately and repeatably measuring bare peat extent using ground surveys, in 2005; and (ii) comparing the fullness of pools (strictly, pool area covered in standing water) using aerial photographs taken during 1946–2016. Estimated bare peat cover in the study area in 2005 was 10.5 % (95 % confidence limits 6.8–15). When placing a horizontal 1 m cane on the ground, bare peat was recorded under an average of 2.7 (2.2–3.2) 10 cm sections out of a possible maximum of ten per cane. Bare peat was most extensive on the flattest ground. Pools largely covered by standing water made up 30–60 % of pools in five pool groups, in five surveys during 1946–2005; but 75 % (standard error ~ 8) in 2016 - significantly higher than some earlier years. Active restoration management is merited for anthropogenic erosion but is more questionable for erosion that arose naturally or shows strong spontaneous recovery. We recommend follow-up studies during the next ten years to clarify the trajectories and causes of erosion at Knockfin; specifically, a repeat of this ground survey alongside remote sensing, experimental and palaeoecological work.

The response of peatland carbon accumulation to climate can be complex, with internal feedbacks and processes that can dampen or amplify responses to external forcing. Records of carbon accumulation from peat cores provide a record of carbon which persists as peat over long periods of time, demonstrating the long-term response of peatland carbon stocks to climatic events. Numerous records of long-term carbon accumulation exist globally. However, peatlands from oceanic climates, and particularly blanket bog, remain under-represented. Scottish bogs, which collectively have more than 475 separate palaeoecological records, may prove to be a valuable resource for studying the impact of environmental change on past rates of carbon accumulation. Here we present 12 records of carbon accumulation from the north of Scotland. We support these results with a further 43 records where potential carbon accumulation is inferred from published ages. These reveal a trend of high carbon accumulation in the early Holocene, declining in the mid-to-late Holocene. The trend is consistent with accumulation profiles from other northern peatlands and is likely to have been caused by climatic cooling. Considerable variability in carbon accumulation rates between locations is apparent for the mid-to-late Holocene. We attribute to hydrologically induced changes in carbon accumulation which are likely to be inconsistent between sites.

Afforestation of formerly open landscapes can transform mammalian predator communities, potentially impacting prey species like ground‐nesting birds. In Scotland's Flow Country, a globally important peatland containing many forestry plantations, earlier studies found reduced densities of breeding waders on open bogs, when forestry plantations were present within 700 m. One plausible explanation for this pattern is mammalian predation. We tested whether mammalian predator indices, based on scats (feces), differed between (1) open bog, forestry plantations, and former plantations being restored as bog ("restoration" habitats); (2) restoration habitats of different ages; and (3) open bogs with differing amounts of nearby forestry. We measured summer scat density and size over 14 years in 26 transects 0.6–4.5 km in length, collecting data during 93, 96, and 79 transect‐years in bog, forestry, and restoration habitats respectively. In forestry, scat density increased eightfold, reaching values ~6 times higher than those of bogs. On open bogs with over 10% forestry within 700 m, scat densities were 2.9 times higher than on open bogs with less forestry nearby. Results support the hypothesis that mammalian predators might be responsible for the low densities of breeding waders close to forests, on adjacent open bogs. In restoration habitats, scat densities rose 6–10 years after felling but fell to levels similar to open bogs in older restoration habitats, supporting restoration management as a means of reducing mammalian predator activity/abundance. We urge caution around decisions to establish forestry plantations in open landscapes of high biodiversity importance. [ABSTRACT FROM AUTHOR]

Background. Over 25% of the UK land area is covered by uplands, the bulk of which are comprised of blanket bog. This not only contains most of the UK’s terrestrial carbon stocks, but also represents 15% of this globally rare habitat. About 30% of UK blanket bog is managed for red grouse by encouraging ling heather (Calluna vulgaris) with rotational burning, which has been linked to habitat degradation, with reduced carbon storage and negative impacts on water storage and quality. Alternative cutting is currently being pursued as a potential restoration management. However, the often used heavy cutting machinery could cause considerable compaction and damage to the peat surface. Two particular issues are (i) a potential increase in bulk density reducing water storage capacity (i.e., less pore volume and peat depth), and (ii) a possible reduction of the micro-topography due to cutting off the tops of hummocks (i.e., protruding clumps or tussocks of sedges). Methods. We set up a fully replicated field experiment assessing cutting versus burn management impacts on peat physical and surface properties. Both managements reflected commonly used grouse moor management practice with cutting using heavy tractors fitted with load distributing double wheel and tracks (lowering ground pressure), whilst burning was done manually (setting heather areas alight with flame torches). We assessed management impacts on peat depth, bulk density and peat surface micro-topography which either included pre-management measurements or plot-level data for uncut plots. Total peat depth and bulk density in four 5 cm sections within the top 50 cm was assessed. Micro-topography was determined as the standard deviation of the height offsets measured over several plot transects in relation to the plot peat surface level at the start and end points of each transect. Results. Despite an anticipated compaction from the heavy machinery used for cutting, the peat showed resilience and there was no lasting plot-level impact on either peat depth or bulk density. Notably, bulk density showed differences prior to, and thus unrelated to, management, and an overall increasing bulk density, even in uncut plots. However, cutting did reduce the plot micro-topography by about 2 cm, mostly due to removing the tops of hummocks, whereas burnt plots did not differ from uncut plots. Discussion. Cutting is suggested as a suitable alternative to burning on grouse moors, although compaction issues might be site specific, depending on the nature of the peat, the machinery used and impacts at resting and turning points (which were not assessed). However, any observed bulk density differences could reflect natural changes in relation to changes in peat moisture, requiring adequate experimental comparisons. Moreover, where micro-topography is a priority, cutting equipment might need to consider the specific ground conditions, which could involve adjusting cutting height and the type of cutting machinery used. [ABSTRACT FROM AUTHOR]

Peatlands are recognised as an important but vulnerable ecological resource. Understanding the effects of existing damage, in this case erosion, enables more informed land management decisions to be made. Over the growing seasons of 2013 and 2014 photosynthesis and ecosystem respiration were measured using closed chamber techniques within vegetated haggs and erosional peat pans in Dartmoor National Park, southwest England. Below-ground total and heterotrophic respiration were measured and autotrophic respiration estimated from the vegetated haggs. The mean water table was significantly higher in the peat pans than in the vegetated haggs; because of this, and the switching from submerged to dry peat, there were differences in vegetation composition, photosynthesis and ecosystem respiration. In the peat pans photosynthetic CO2 uptake and ecosystem respiration were greater than in the vegetated haggs and strongly dependent on the depth to water table (r2 > 0.78, p < 0.001). Whilst in the vegetated haggs, photosynthesis and ecosystem respiration had the strongest relationships with normalised difference vegetation index (NDVI) (r2 = 0.82, p < 0.001) and soil temperature at 15 cm depth (r2 = 0.77, p = 0.001). Autotrophic and total below-ground respiration in the vegetated haggs varied with soil temperature; heterotrophic respiration increased as water tables fell. An empirically derived net ecosystem model estimated that over the two growing seasons both the vegetated haggs (29 and 20 gC m−2; 95% confidence intervals of − 570 to 762 and − 873 to 1105 gC m−2) and the peat pans (7 and 8 gC m−2; 95% confidence intervals of − 147 to 465 and − 136 to 436 gC m−2) were most likely net CO2 sources. This study suggests that not only the visibly degraded bare peat pans but also the surrounding vegetated haggs are losing carbon to the atmosphere, particularly during warmer and drier conditions, highlighting a need for ecohydrological restoration. [ABSTRACT FROM AUTHOR]

Peatlands are important reserves of terrestrial carbon and biodiversity, and given that many peatlands across the UK and Europe exist in a degraded state, their conservation is a major area of concern and a focus of considerable research. Aerial surveys are valuable tools for habitat mapping and conservation and provide useful insights into their condition. We investigate how SfM photogrammetry-derived topography and habitat classes may be used to construct an estimate of carbon loss from erosion features in a remote blanket bog habitat. An autonomous, unmanned, aerial, fixed-wing remote sensing platform (Quest UAV 300™) collected imagery over Moor House, in the Upper Teesdale National Nature Reserve, a site with a high degree of peatland erosion. The images were used to generate point clouds into orthomosaics and digital surface models using SfM photogrammetry techniques, georeferenced and subsequently used to classify vegetation and peatland features. A classification of peatbog feature types was developed using a random forest classification model trained on field survey data and applied to UAV-captured products including the orthomosaic, digital surface model and derived surfaces such as topographic index, slope and aspect maps. Using the area classified as eroded peat and the derived digital surface model, we estimated a loss of 438 tonnes of carbon from a single gully. The UAV system was relatively straightforward to deploy in such a remote and unimproved area. SfM photogrammetry, imagery and random forest modelling obtained classification accuracies of between 42% and 100%, and was able to discern between bare peat, saturated bog and sphagnum habitats. This paper shows what can be achieved with low-cost UAVs equipped with consumer grade camera equipment and relatively straightforward ground control, and demonstrates their potential for the carbon and peatland conservation research community. [ABSTRACT FROM AUTHOR]

Fire, including prescribed burning, is common on peatlands globally and can affect vegetation, including peat-forming Sphagnum mosses, and affect ecosystem services. We monitored vegetation in different burn-age categories at three UK peatland sites over a 19-month period. Half of the plots had Sphagnum fragments added and their survival was assessed. Changes in vegetation composition over time, and associations between vegetation composition, site and burn-age category were investigated. Plots in the most recently burned category were likely to have more bare peat, a thinner moss layer and lower vascular plant strata. Graminoid cover initially increased after burning but was low after 10 + years. Dwarf shrub cover increased after burning and remained high after 10 + years. At the most Sphagnum-rich site, a high proportion of existing Sphagnum cover was bleached one year after burning, but recovery occurred during the study period. Sphagnum re-introduction success decreased over the study period in the most recent and intermediate burn-age categories at the most Sphagnum-poor site. These results show that burning rotation length is an important factor in determining site-level vegetation composition on burned sites. More frequent burning will result in a greater proportion of land in the early post-burning stages, potentially resulting in a thinner moss layer, more bare peat and less healthy Sphagnum, with potential consequences for carbon balance. No evidence was found to support the use of burning as a tool to increase existing Sphagnum or promote Sphagnum re-establishment success. [ABSTRACT FROM AUTHOR]

The globally widespread drainage of peatlands has often been shown to lead to increased concentrations and fluxes of dissolved organic carbon (DOC) in streams and rivers. Elevated DOC concentrations have implications for carbon cycling, ecosystem functioning, and potable water treatment. Peatland rewetting, principally through ditch blocking, is often carried out with the expectation that this will reduce DOC concentrations. Uncertainty still remains as to whether drainage, or its reversal via ditch blocking, will also lead to changes in the molecular composition of DOC/dissolved organic matter (DOM), which have the potential to affect downstream processing and treatability of U.K. drinking water supplies. To investigate this question, we used a replicated experiment consisting of 12 parallel ditches on an upland bog and took samples of ditch water, pore water, and overland flow water for 4 years. After a brief preblocking baseline period, eight ditches were blocked using two methods. A complementary suite of optical metrics, chemical measurements, and analytical techniques revealed that ditch blocking had no consistent effect on DOM quality, up to 4 years after blocking. Where significant differences were found, effect size calculations demonstrated that these differences were small and would therefore have minimal impact upon water treatability. Furthermore, some differences between ditches were evident before blocking took place, highlighting the need for robust baseline monitoring before intervention. Based on our results from a hillslope‐scale experiment, we were unable to identify clear evidence that peatland ditch blocking will deliver benefits in terms of DOM treatability in potable water supplies, although we also did not find any evidence of short‐term deterioration in water quality during the restoration period. We conclude that, although peatland restoration can be expected to deliver other benefits such as reduced carbon loss and enhanced biodiversity, it is doubtful whether it will lead to improvements in drinking water treatability. [ABSTRACT FROM AUTHOR]

Peatland erosion has important implications for ecosystem services such as carbon storage and biodiversity conservation. The extensive blanket bogs of Scotland's Flow Country include some of the least damaged peatlands in the UK; nevertheless, erosion features occur widely in the area. Here we describe a high-altitude (340-440 m) heavily eroded peatland at Knockfin Heights in the Flow Country. The causes of this erosion are poorly understood, and could include both human and natural factors. Restoration management has been considered for the site, although this might be unnecessary if spontaneous recovery is taking place. Our study aimed to contribute to understanding whether recovery was occurring, by (i) accurately and repeatably measuring bare peat extent using ground surveys, in 2005; and (ii) comparing the fullness of pools (strictly, pool area covered in standing water) using aerial photographs taken during 1946-2016. Estimated bare peat cover in the study area in 2005 was 10.5% (95% confidence limits 6.8-15). When placing a horizontal 1 m cane on the ground, bare peat was recorded under an average of 2.7 (2.2-3.2) 10 cm sections out of a possible maximum of ten per cane. Bare peat was most extensive on the flattest ground. Pools largely covered by standing water made up 30-60% of pools in five pool groups, in five surveys during 1946-2005; but 75% (standard error ~ 8) in 2016 - significantly higher than some earlier years. Active restoration management is merited for anthropogenic erosion but is more questionable for erosion that arose naturally or shows strong spontaneous recovery. We recommend follow-up studies during the next ten years to clarify the trajectories and causes of erosion at Knockfin; specifically, a repeat of this ground survey alongside remote sensing, experimental and palaeoecological work. [ABSTRACT FROM AUTHOR]

The response of peatland carbon accumulation to climate can be complex, with internal feedbacks and processes that can dampen or amplify responses to external forcing. Records of carbon accumulation from peat cores provide a record of carbon which persists as peat over long periods of time, demonstrating the long-term response of peatland carbon stocks to climatic events. Numerous records of long-term carbon accumulation exist globally. However, peatlands from oceanic climates, and particularly blanket bog, remain underrepresented. Scottish bogs, which collectively have more than 475 separate palaeoecological records, may prove to be a valuable resource for studying the impact of environmental change on past rates of carbon accumulation. Here we present 12 records of carbon accumulation from the north of Scotland. We support these results with a further 43 records where potential carbon accumulation is inferred from published ages. These reveal a trend of high carbon accumulation in the early Holocene, declining in the mid-to-late Holocene. The trend is consistent with accumulation profiles from other northern peatlands and is likely to have been caused by climatic cooling. Considerable variability in carbon accumulation rates between locations is apparent for the mid-to-late Holocene. We attribute to hydrologically induced changes in carbon accumulation which are likely to be inconsistent between sites. [ABSTRACT FROM AUTHOR]

The frequency of individual plant species at ground level and the species composition of the unimproved vegetation on a western hill farm, stocked with Scottish Blackface sheep, were monitored from 1995 to 2008. Performance criteria of the flock that relied totally, or almost totally, on this vegetation for sustenance from 1994 to 2011 were evaluated. The frequency of vegetation increased over time (from 65% to 82% of the surface area; P < 0.05), with a corresponding decline in the frequency of bare soil, thus reducing vulnerability to soil erosion. This increased incidence of vegetation cover reflected increases in ‘other forbs’(P < 0.01), heather(P < 0.05)and grass (P < 0.08).A significant change (P < 0.05) also occurred in the species composition of the vegetation, reflecting an increase in the proportions of ‘other forbs’ (P < 0.05) and heather (P = 0.14), and a decline in the proportion of sedges (P = 0.14). A similar pattern occurred in the two main habitats: blanket bog and wet heath. Annual stocking rate (ewes per hectare, based on actual ewe grazing days) on the unimproved hill grazing averaged 0.9 (0.13 livestock units) per hectare prior to 1999 and 0.78 (0.11 livestock units) per hectare subsequently. There was no trend in weight gain of replacement females while confined to the unimproved hill area between weaning (14 weeks old) and first joining at 18 months of age. A negative trend (P < 0.01) occurred in the pre-weaning growth rate of lambs on the hill. The average number of lambs reared per ewe joined (reflecting fertility, litter size and ewe/lamb mortality) was 1.0, and this showed no evidence of change over time. The study flock performed 10% to > 60% better, depending on the variable, than similar flocks in the National Farm Survey at comparable stocking rates. A well-defined rational management system can sustain a productive sheep enterprise on unimproved hill land without negative consequences for the frequency or composition of the vegetation.

The regional/national carbon (C) stock of peatlands is often poorly characterised, even for comparatively well-studied areas. A key obstacle to better estimates of landscape C stock is the scarcity of data on peat depth, leading to simplistic assumptions. New measurements of peat depth become unrealistically resource-intensive when considering large areas. Therefore, it is imperative to maximise the use of pre-existing datasets. Here we propose that one potentially valuable and currently unexploited source of peat depth data is palaeoecological studies. We discuss the value of these data and present an initial compilation for Scotland (United Kingdom) which consists of records from 437 sites and yields an average depth of 282 cm per site. This figure is likely to be an over-estimate of true average peat depth and is greater than figures used in current estimates of peatland C stock. Depth data from palaeoecological studies have the advantages of wide distribution, high quality, and often the inclusion of valuable supporting information; but also the disadvantage of spatial bias due to the differing motivations of the original researchers. When combined with other data sources, each with its own advantages and limitations, we believe that palaeoecological datasets can make an important contribution to better-constrained estimates of peat depth which, in turn, will lead to better estimates of peatland landscape carbon stock.

We investigated the effects of ditch blocking on fluvial carbon concentrations and fluxes at a 5‐year, replicated, control‐intervention field experiment on a blanket peatland in North Wales, UK. The site was hydrologically instrumented, and run‐off via open and blocked ditches was analysed for dissolved organic carbon (DOC), particulate organic carbon, dissolved carbon dioxide, and dissolved methane. DOC was also analysed in peat porewater and overland flow. The hillslope experiment was embedded within a paired control‐intervention catchment study, with 3 years of preblocking and 6 years of postblocking data. Results from the hillslope showed large reductions in discharge via blocked ditches, with water partly redirected into hillslope surface and subsurface flows, and partly into remaining open ditches. We observed no impacts of ditch blocking on DOC, particulate organic carbon, dissolved carbon dioxide or methane in ditch waters, DOC in porewaters or overland flow, or stream water DOC at the paired catchment scale. Similar DOC concentrations in ditch water, overland flow, and porewater suggest that diverting flow from the ditch network to surface or subsurface flow had a limited impact on concentrations or fluxes of DOC entering the stream network. The subdued response of fluvial carbon to ditch blocking in our study may be attributable to the relatively low susceptibility of blanket peatlands to drainage, or to physical alterations of the peat since drainage. We conclude that ditch blocking cannot be always be expected to deliver reductions in fluvial carbon loss, or improvements in the quality of drinking water supplies. [ABSTRACT FROM AUTHOR]

The effect of prescribed burning for conservation management of plant communities is controversial for moorlands growing on peat. These ecosystems provide many services that may be damaged by fire, hence it is important to fully assess its impact on all aspects of ecosystem structure and function experimentally over relatively long time-scales. This paper describes change in community composition, major plant species, and plant functional types on moorland on peat in upland Britain over 60 years subject to 3 burning treatments after an initial burn in 1954/1955: no further burn and burning at 10- and 20-year intervals (all ± sheep grazing). Data were analysed using multivariate and univariate methods. Vegetation composition and individual species abundance reflected the degree of disturbance. The least disturbed was dominated by Calluna vulgaris and pleurocarpous mosses, whereas the most disturbed treatment (burned every 10 years) had greater Eriophorum vaginatum, Sphagnum spp., acrocarpous mosses, liverworts, and lichens. The 20-year treatment was intermediate in response disturbance. Repeated burning increased species abundance-weighted Ellenberg values for moisture, reaction, light through time, and fertility; the exception was the 10-year rotation for fertility. These confirm that prescribed burning is not deleterious to peat-forming species (Eriophorum spp. and Sphagnum spp.), indeed these species were found in greater abundance in frequently burned treatments. It also confirms that a no-burn policy will lead to increasing dominance of C. vulgaris, a flammable, fire-adapted shrub, which increases summer wildfire risk. These results inform conservation management policy for moorland vegetation growing on peat; for this site, a 20-year prescribed burning rotation is recommended. [ABSTRACT FROM AUTHOR]

In north-west Europe, large areas of open peatland have been drained and planted with spatially homogenous stands of non-native conifers. The detrimental impact of afforestation on peatland carbon and biodiversity have led to large-scale attempts to restore these landscapes back to their open, tree-less form. The responses of dominant microbial consumers − testate amoebae − to peatland forest-to-bog restoration are largely unexplored. We studied changes in testate amoebae with forest-to-bog restoration in the largest expanse of blanket bog in the UK and compared testate amoeba communities in relatively undisturbed open bog with forested and forest-to-bog restoration sites. Forested areas contained testate amoeba communities which were functionally different from open bog, characterised by a lack of mixotrophic taxa known to contribute to primary production. Seventeen years after restoration management, the microbial communities in the forest-to-bog sites remained more similar to forested areas than to the open bog community. Our results suggest that afforestation has reduced the trophic level of testate amoeba communities, which are only beginning to recover post-restoration in the wettest areas where Sphagnum has re-colonized. This study also highlights the need to consider a wide-range of reference sites to encompass the natural variability within ombrotrophic blanket bog. We conclude that testate amoebae have the potential to act as functionally-significant bio-indicators in peatlands undergoing forest-to-bog restoration. [ABSTRACT FROM AUTHOR]

Background: In the UK, government legislation allows the use of prescribed fire in peatlands for land management purposes. The use of fire, however, remains controversial, partly because of a distinct lack of data on the response of key peatland species to fire.Sphagnumspecies are key components of peatland ecosystems, yet a fundamental knowledge gap in the debate is the response ofSphagnumspecies to fire. Aims: To determine if a widespread species (Sphagnum capillifolium) has the ability to recover from exposure to high temperatures, analogous to those recorded in managed peatland fires. Methods: Samples ofS. capillifoliumwere exposed to a range of temperature treatments. Recovery was monitored using chlorophyll fluorescence, CO2exchange and physical damage and new growth assessed. Results: We found that the degree of recovery ofS. capillifoliumwas related to the temperature treatment, post-treatment environmental conditions and pre-treatment stem moisture content. The slowest recovery was found when samples were heated to 400°C for 30 s. Conclusions: Our results demonstrate thatS. capillifoliumhas the ability to recover following exposure to the temperatures experienced in prescribed fire, provided that at least some living material remains. Our results suggest that prescribed burning in the spring may allow for a quicker recovery than autumnal fires. [ABSTRACT FROM AUTHOR]

This study deals with the palaeohydrological information obtained from lipids composition and vegetal tissue preservation of two peat cores from Asturias, North Spain. The two profiles differ in the type of peatland (raised bog in La Borbolla and blanket bog in Buelna) and the type of organic matter being more bryophytic in the raised bog and more herbaceous in the blanket bog. The peatlands are located close to the coast on impermeable, old flat erosion surfaces which favoured peat accumulation within a distance of 3.5 km from each other. The accumulation rate varied between 0.05 and 0.07 mm/yr and the records extend from around 9000 to 2500 cal. yr BP. The main differences between the two peat sites can be summarized as follows: the raised bog has lower mineral matter content and H/C atomic ratio and higher C/N ratio and extraction yields compared to the blanket bog. It has also a higher Tissue Preservation Index for Huminite macerals and increasing Inertodetrinite Index with depth. Regarding biomarkers, the raised bog has a relatively higher concentration of n- alkane-2-ones compared to the corresponding n- alkane of similar carbon number, higher concentration of medium- vs. high-molecular-weight-methyl-ketones and higher triterpenoids/steroids ratio than the blanket bog. Alternating humid/dry periods have been recorded in both profiles based on lipid concentrations indicating that the Sphagnum -rich intervals in the raised bog are more sensitive than the herbaceous blanket peat record to climatic variations. The main humid intervals identified are dated as 5000–7500 cal. yr BP in the blanket bog and as 6000–3500 cal. yr BP and last 2500 cal. yr BP in the raised bog and correlate with the humid periods traced in other peatlands locations in this region. The transition Middle-to-Late Holocene is characterized by humid conditions in the region which favoured the Sphagnum growth in the peats. The reflectance of huminite in these records appears to be more related with differences in the oxidative conditions than with variation of peat maturity. It is higher in the layers with high mineral matter content at the beginning of organic matter accumulation and also in the upper part of the profile subjected to seasonal desiccation. A more intense biochemical gelification coincides with higher concentration of hopanoids derived from bacteria in the upper part of the profile (acrotelm). High amount of nonadecan-2-one (K 19 ) and high concentrations of triterpenyl acetates, which are also determined in other peat profiles from Northern Spain are also detected in these profiles. This indicates that the specific conditions required for the formation of these compounds, probably associated to wet temperate climate, dominated throughout the region. [ABSTRACT FROM AUTHOR]

We analysed data collected between 1954 and 2000 from nine long-term experiments designed to assess the effects of sheep-grazing versus no-sheep-grazing at Moor House NNR, an Environmental Change Network site. The experiments were set up between 1954 and 1972 across a range of vegetation types typical of much of upland Britain. Data from this type of experiment are often difficult to analyse and we describe the procedures undertaken to prepare the data for analysis. We fitted the resultant data to the British National Vegetation Classification and used ordination techniques to assess the relative positions of the experiments to each other. Finally, we used Generalized Linear Mixed-effects Modelling within a Bayesian framework to model change of species taxonomic/physiognomic groups through time in both sheep-grazed and ungrazed treatments across all nine experiments; variables included species diversity, Shannon–Weiner index and derived data on occurrence and abundance of species groups based on taxonomy and physiognomy. Hurdle analysis was used to model the species groups; this analysis separated the change through time in both probability of occurrence (binomial distribution) and abundance (Poisson distribution). In the sheep-grazed plots (the “business-as-usual” treatment hence here designated the “control”) there was a reduction in species diversity and a decrease in abundance of vascular plants, grasses, lichens, liverworts and mosses; whereas herbs, sedges and shrubs increased. When probability of occurrence was considered, there was a reduction in number of presences of both lichens and liverworts. Thus, the status quo management of continuous sheep-grazing, even though reduced since 1972, has resulted in a marked change in species composition of these plant communities, with some winners and some losers, but overall they support the concept of biotic homogenization. It is likely that some of these changes were driven by external factors such as elevated atmospheric nutrient deposition. Removal of sheep grazing had some positive benefits; with the herbs, mosses, sedges and shrubs increasing, but faster reductions in grasses and liverworts. Sedges + rushes were stable. It suggested that future monitoring schemes might use either the probability of occurrence of liverworts and lichens, or the abundance of lichens, liverworts, grasses and mosses as sensitive indicators of change in upland Britain. Moreover, during the period that Moor House has been protected as a nature reserve some key plant species groups have declined in spite of reductions in grazing pressure. To reverse this trend requires some form of interventionist management. In order to increase the diversity of vascular plants some form of disturbance will probably be needed, but for bryophytes and lichens this remains a research question. If the results from these small-scale experiments are replicated at the landscape scale a reduction of sheep grazing pressure, for example in rewilding schemes, will have little effect on species composition over a 28–44 year period. [ABSTRACT FROM AUTHOR]

Ombrotrophic peatlands have provided important archives for understanding Holocene palaeoenvironmental change. However, records are predominantly from raised bogs due to potential issues regarding preservation of proxy indicators, record length and low temporal resolution in other peat types including blanket bogs. By carrying out peat depth and stratigraphy surveys we demonstrate how blanket peatlands can provide archives capable of providing records that are not reliant on single proxies, as has been often the case in the past, and can provide good resolution records. A record containing humification, testate amoebae and plant macrofossils was derived for the last 3000 years with accumulation rates as high as 8 yrs cm − 1 providing favourable temporal resolution, particularly over the last 1500 years. Major changes in proxy indicators reflecting potential changes in water-table depth were often coherent with changes in climate. Human activity also had a major impact on the peatland throughout the record especially in the last 100 years where the influence of wildfire and managed burning, together with an effect of atmospheric pollution, fundamentally changed the state of the peatland. [ABSTRACT FROM AUTHOR]

This study investigates the causes of erosion and degradation of March Haigh, a blanket mire in the southern Pennines (UK), over a period of 160 years starting in 1840 AD. Peat samples taken from the site were dated using 210Pb; their humification and magnetic susceptibility were measured; and they were examined for pollen, plant macrofossils and microscopic charcoal. Stratigraphic correlation with a dated ‘master’ sample was achieved using indicators of air pollution (magnetic susceptibility) and climate (peat humification). The data were used in conjunction with documentary records to reconstruct past variations in grazing pressure, climate, moorland fires and air pollution. Three major vegetation changes have occurred on the moorland since 1840, namely: (1)the disappearance of Sphagnum spp. in the mid 19th century; (2)the replacement of Calluna vulgaris by Poaceae as the dominant vegetation type ca. 1918; and (3)a reduction in vegetation cover and consequent erosion ca. 1959. The results concur with the findings of other investigations of ecological change in the southern Pennines insofar as degradation of vegetation prior to the mid 20th century appears to have been caused by air pollution, climate change and fire. Following the removal of vegetation by a severe fire during the summer of 1959, unprecedented sheep stocking levels maintained the bare peat surface and thus precipitated extensive erosion.

Burning for habitat management is globally widespread. Burning over carbon-rich soils is a global environmental concern due to the potential contribution to climate change. In the UK, upland heath and blanket bog, so-called 'moorland', often overlies carbon-rich soils, and has internationally important conservation value, but is burned as management for gamebird shooting and to a lesser extent for livestock grazing. There is little detailed information on the spatial extent or temporal trends in burning across the UK. This hinders formulation of policies for sustainable management, given that the practice is potentially detrimental for soil carbon storage, water quality and habitat condition. Using remotely sensed data, we mapped burning for gamebird management across c45 000 km 2 of the UK. Burning occurred across 8551 1-km squares, a third of the burned squares in Scotland and England were on peat ≥ 0.5 m in depth, and the proportion of moorland burned within squares peaked at peat depths of 1–2 m. Burning was detected within 55% of Special Areas of Conservation and 63% of Special Protection Areas that were assessed, and the proportion of moorland burned was significantly higher inside sites than on comparable squares outside protected areas. The annual numbers of burns increased from 2001 to 2011 irrespective of peat depth. The spatial overlap of burning with peat and protected areas and the increasing number of burns require urgent attention, for the development of policies for sustainable management and reversal of damage to ecosystem services in the UK uplands. [ABSTRACT FROM AUTHOR]

[Display omitted] • We measured change in four British upland communities between 1953 and 2016. • Replicated grazed-ungrazed plots were compared at 12 sites within 4 communities. • We modelled long-term change in richness and abundance of 4 plant taxonomic groups. • There is evidence of post-2000 recovery in vascular plants and mosses. • There is limited liverwort and no lichen recovery; they are a restoration priority. The upland and mountainous regions of northern Europe provide a wide variety of ecosystem services. However, these ecosystem services are highly vulnerable to environmental and land-use change. To ensure their future conservation, it is therefore, essential to understand whether upland plant communities will respond positively or negatively to a range of environmental factors such as grazing pressure and landscape-scale factors such as changes in atmospheric SO 2 and NO x deposition. To understand this, here, we describe the long-term trends in four UK upland communities (high-level grassland, intermediate grassland, blanket bog, high-level bog) using four replicated long-term experiments examining the effects of sheep grazing compared to no-sheep grazing in Moor House (from 1954 to 2016). Our results showed that species richness and abundance recovered in grazed plots after 2000, with improvements in species richness and abundance of vascular plants, mosses, and liverworts. Unfortunately, no improvement was found for lichens. Species richness, vascular plants, and mosses recovered the fastest, and much faster than liverworts. There was no evidence of slower recovery of species richness and abundance in plots where sheep grazing was removed. These results are consistent with longitudinal studies suggesting recovery after 2000 as a result of reduced atmospheric deposition. Although trends in diversity and abundance in the grazed and ungrazed plots were not identical, they were not markedly different either. The similar richness and abundance trends in the grazed and ungrazed plots found in each plant community suggest that within-community dynamics may overcome initial differences between the grazing treatments over time. In contrast, differences in richness and abundance among plant communities over time suggest that some landscape-scale trends, such as those caused by a reduction in nutrient inputs, initiate community-dependent recovery. [ABSTRACT FROM AUTHOR]

Peatlands are large terrestrial stores of carbon, and sustained CO sinks, but over the last century large areas have been drained for agriculture and forestry, potentially converting them into net carbon sources. More recently, some peatlands have been re-wetted by blocking drainage ditches, with the aims of enhancing biodiversity, mitigating flooding, and promoting carbon storage. One potential detrimental consequence of peatland re-wetting is an increase in methane (CH) emissions, offsetting the benefits of increased CO sequestration. We examined differences in CH emissions between an area of ditch-drained blanket bog, and an adjacent area where drainage ditches were recently infilled. Results showed that Eriophorum vaginatum colonization led to a 'hotspot' of CH emissions from the infilled ditches themselves, with smaller increases in CH from other re-wetted areas. Extrapolated to the area of blanket bog surrounding the study site, we estimated that CH emissions were around 60 kg CH ha y prior to drainage, reducing to 44 kg CH ha y after drainage. We calculated that fully re-wetting this area would initially increase emissions to a peak of around 120 kg CH ha y, with around two-thirds of the increase (and 90% of the increase over pre-drainage conditions) attributable to CH emissions from E. vaginatum-colonized infilled ditches, despite these areas only occupying 7% of the landscape. We predicted that emissions should eventually decline toward pre-drainage values as the ecosystem recovers, but only if Sphagnum mosses displace E. vaginatum from the infilled ditches. These results have implications for peatland management for climate change mitigation, suggesting that restoration methods should aim, if possible, to avoid the colonization of infilled ditches by aerenchymatous species such as E. vaginatum, and to encourage Sphagnum establishment. [ABSTRACT FROM AUTHOR]

This study aimed to measure the effects of ecological restoration on blanket peat water table depths and CO fluxes. The flux of CO and water table depths were measured on eight sites for 5 years. Results suggest that sites with revegetation alongside slope stabilisation have the highest rates of photosynthesis and are the largest net (daylight hours) sinks of CO. Bare sites are the largest net sources of CO and have the deepest water table depths. Sites with gully wall stabilisation are between 5 and 8 times more likely to be net CO sinks than the bare sites. Revegetation without gully flow blocking using plastic dams does not have a large effect on water table depths in and around the gullies investigated whereas a blocked gully has water table depths comparable to a naturally revegetating gully. A 10 cm lowering in water table depth decreases the probability of observing a net CO sink, on a given site, by up to 30 %. The most important conclusion of this research was that restoration interventions are effective at increasing the likelihood of net CO sink behaviour and raising water tables on degraded, climatically marginal blanket bog. [ABSTRACT FROM AUTHOR]