Grouse Moors Research Articles

Voices in a contested landscape: community participation and upland management in the North York Moors National Park

The moorland plateau is the defining landscape of the North York Moors National Park in England. It reflects the everyday management decisions of land managers and the complex web of power relations between multiple stakeholders. The moorland is a contested, shared space that poses questions over access, habitat conservation, biodiversity, grouse shooting, land management, and ultimately, the purpose of National Park landscapes. This article draws upon a mixed methods approach and a heritage-landscape perspective to analyse community viewpoints of the management, use, and ownership of this landscape and to demonstrate how power relations frame human-nature synergies in the Park. In doing so, the article highlights new ways that North York Moors communities could be better represented in discussions on how landscapes are perceived, valued, and managed. It proposes a system that amalgamates key decision makers and residents and, therefore, involves a wider range of stakeholders in the landscape decision-making process.

Illegal killing associated with gamebird management accounts for up to three-quarters of annual mortality in Hen Harriers Circus cyaneus

Predators are frequently victims of wildlife crime due to conflicts with human interests. Where predators are protected, killing may occur covertly and novel methods, including satellite tracking, are often required to assess population consequences. Wildlife crime persists in the British uplands, where raptors are illegally killed on moorland managed for Red Grouse Lagopus lagopus scotica shooting. To understand impacts on one such species, the Hen Harrier Circus cyaneus, we analysed data from 148 individuals tracked across Britain between 2014 and 2021. Using remotely sensed land-use data and continuous-time survival methods, we quantified survival rates, contributions of natural causes and illegal killing to mortality, and spatial and temporal associations between mortality and land managed for grouse shooting. Annual survival was low, especially among first-year birds (males: 14 %; females: 30 %), with illegal killing accounting for 27–43 % and 75 % of mortality in first-year and subadult (1-2 years) harriers respectively. Illegal killing is likely attributable to grouse moor management because i) a 10 % increase in grouse moor use resulted in a 43 % increase in mortality risk; ii) a strong overlap existed between mortality and grouse moor extent in 20 km squares, identifying hotspots of illegal killing in northern England and northeast Scotland; iii) death due to natural causes showed different spatial and temporal patterns; and iv) timing of mortality peaked around the shooting season and during breeding territory establishment. Governments have failed to reduce illegal killing of Hen Harriers and other raptors in Britain and our results emphasise that further legislative reform is needed to tackle this enduring criminality.

Modelling important areas for breeding waders as a tool to target conservation and minimise conflicts with land use change

Breeding waders are high profile species of conservation concern because of their declining populations. Their future depends on the outcomes of land-use policy and local management decisions. However, the low spatial resolution of extensive data on wader occurrence is poorly suited to directing conservation initiatives or to minimising detrimental impacts arising from land-use changes such as forest expansion. We used statistical models to produce high-resolution maps of predicted wader abundance in Britain and tested whether these were sufficiently accurate to be used for decision making. Random forest regression trees were developed using Bird Atlas data modelled with a range of environmental data sets to predict the relative abundances of ten species of breeding wader across Britain at 1-km square resolution. Similar analytical frameworks could usefully be applied in other geographical areas.Correlations with Bird Atlas metrics and other independent data indicate that these predictive models worked best for Curlew Numenius arquata and Oystercatcher Haematopus ostralegus. Model performance was poorer for species with more restricted distributions and/or habitat requirements, such as Greenshank Tringa nebularia and Ringed Plover Charadrius hiaticula. The precision of model predictions was also limited by the rescaling of data to 1-km square resolution.To facilitate practical and consistent interpretation by stakeholders influencing the status of breeding waders, model outputs were categorised into five discrete strata of relative abundance. These strata were used to produce sensitivity maps (available at https://app.bto.org/wader-map/), primarily to inform high-level policy decisions. The model outputs were also used to investigate broad-scale associations of breeding wader distribution with landscapes and land uses. These show that high proportions of populations (relative to their extent) are supported by areas with comparatively low predation risk (e.g. islands and grouse moors) and also by nature reserves. At more local scales, the sensitivity maps can be used to help decide on the levels of scrutiny required to assess development proposals (e.g. for establishment of new tree planting).

Retrospective comparisons of competing demographic models give clarity from "messy" management on a Scottish grouse moor.

Retrospective comparison of predictive models that describe competing hypotheses regarding system function can shed light on regulatory mechanisms within the framework of adaptive resource management. We applied this approach to a 28-year study of red grouse (Lagopus lagopus scotica) in Scotland, with the aims of reducing uncertainty regarding important drivers of grouse population dynamics, and of evaluating the efficacy of using seasonal versus annual model assessments. We developed three sets of models that predicted pre-breeding and post-breeding grouse density, matching the timing of grouse counts on the ground. We updated conditions and management through time in the spirit of a real-time, adaptive management program and used a Bayesian model weight updating process to compare model predictions with empirical grouse densities. The first two model sets involved single annual updates from either pre-breeding or post-breeding counts; the third set was updated twice a year. Each model set comprised seven models representing increasingly complex hypotheses regarding potentially important drivers of grouse: the baseline model included weather and parasite effects on productivity, shooting losses and density-dependent overwinter survival; subsequent models incorporated the effect of habitat gain/loss (HAB), control of non-protected predators (NPP) and predation by protected hen harriers (Circus cyaneus, HH) and buzzards (Buteo buteo, BZ). The weight of evidence was consistent across model sets, settling within 10 years on the harrier (NPP + HH), buzzard (NPP + HH + BZ) and buzzard + habitat (NPP + HH + BZ + HAB) models, and downgrading the baseline + habitat, non-protected predator, and non-protected predator + habitat models. By the end of the study only the buzzard and buzzard + habitat models retained substantial weights, emphasizing the dynamical complexity of the system. Habitat inclusion failed to improve model predictions, implying that over the period of this study habitat quantity was unimportant in determining grouse abundance. Comparing annually and biannually assessed model sets, the main difference was in the baseline model, whose weight increased or remained stable when assessed annually, but collapsed when assessed biannually. Our adaptive modeling approach is suitable for many ecological situations in which a complex interplay of factors makes experimental manipulation difficult.

Fight or Flight? Understanding Different Stakeholder Responses to Conservation Conflicts

Efforts to manage conservation conflicts are typically focused on reconciling disputes between opposing stakeholders over conservation objectives. However, this is an oversimplification of conflict dynamics, driven by the difficulties of understanding and addressing deeper-rooted issues. In this study, an ethnographic approach using a combination of informal discussions, participant observation, and in-depth interviews was used to examine local stakeholder narratives around a conservation conflict over grouse shooting and raptor conservation. Analysis highlighted three main narratives – cooperation, resistance, and despondence, that served as a basis for individuals to justify their responses to conflict: to work toward collaboration, act antagonistically, or avoid. Our analysis suggests that the current status quo in conflict management serves to reinforce antagonistic positions. We recommend a more nuanced approach to understanding stakeholder decision-making that goes beyond superficial disputes to recognize diversity within stakeholder groups, access hidden voices, and encompass the wider socio-political context.

Alternative future land use options in the British uplands

A commonly promoted view is that in the absence of driven grouse moor management in the UK uplands, land use on moorland would default to agriculture or afforestation. This forum article questions the orthodoxy of this thinking, discusses alternative scenarios for land use in the uplands and considers the potential effects of these on moorland‐breeding birds.

A cup of tea? – The role of social relationships, networks and learning in land managers’ adaptations to policy change

Within international and, more specifically, European policy there is a shift towards managing land for multiple benefits and in the public interest. This necessitates greater collaboration between different actors, often with diverging management objectives, across a landscape. Here we present the findings of a qualitative study exploring the influence of social relationships, networks and associated power on land managers’ decision-making, collaborative management and implementation of policy change across a national park in Scotland. We found that social relationships and networks were key in facilitating transformative change in land management but could also consolidate the status quo of land management practices and thus hamper change. Consequently, we observed a polarisation of management practices across the national park shaped by social relationships and networks; with one trend towards an intensification of traditional land use (grouse shooting), and another one towards landscape restoration and nature-based solutions. Top-down collaborative groups, composed of participants with divergent views and perspectives, and designed to promote policy uptake, had not yet improved mutual understanding or social learning. By contrast, voluntary collaboration between like-minded estates strengthened existing views, resulting in polarisation. Poor relationships and distrust between some actors constrained social learning and collaborative decision-making between land managers with diverging interests. However, personal one-to-one relationships, developed over time, between agency staff and land managers could moderate patterns of polarisation, where land managers were amenable and had the capacity to make changes to management.Our research shows that collaborative arrangements may not be the silver bullet for policy uptake or adaptation to change. We instead suggest that a better understanding of where social relationships and trust need to be built would be more effective. Explicit attention should also be placed on the design of collaborative processes to increase the sense of fairness, balance out power dynamics and facilitate social learning.

Using satellite data to assess management frequency and rate of regeneration on heather moorlands in England as a resilience indicator

Peatland resilience, defined here as the rate of recovery from perturbation, is crucial to our understanding of the impacts of climate change and land management on these unique ecosystems. Many peatland areas in the UK are managed as grouse moors using small burns (or increasingly, heather cutting) to encourage heather growth and limit fuel load. These small burns or cuts are distinct disturbance events which provide a useful means of assessing resilience. Until now, it has been difficult to monitor the area affected by management each season due to the remoteness and size of moorland sites. Newer satellite sensors such as those on Sentinel-2 are now collecting data at a spatial resolution that is fine enough to detect individual burns or cut areas, and at a temporal resolution which can be used to monitor occurrence and recovery each year. This study considered four areas of moorland; the North Pennines, Yorkshire Dales, North York Moors, and the Peak District. For each of these areas Sentinel-2 optical data was used to detect management areas using the dNBR (differenced Normalized Burn Ratio), and to monitor vegetation recovery using the NDVI (Normalised Difference Vegetation Index). Significant differences were found between the four selected sites in management repeat interval, with the North York Moors having the shortest repeat interval of 20 years on average (compared to 40–66 years across the other three study sites). Recovery times were found to be affected by burn size and severity, weather during the summer months, and altitude. This suggests that the interactions between peatland management and climate change may affect the future resilience of these areas, with hot, dry summers causing longer management recovery times.

Post-burning responses by vegetation on blanket bog peatland sites on a Scottish grouse moor

Burning of ericaceous vegetation on moorland in the United Kingdom is a routine part of management for red grouse (Lagopus lagopus scotica) but its contribution to peatland degradation and loss of key ecosystem services is widely debated. Studies in the North Pennines, northern England, have shown that regular fires at approximately ten-year intervals can benefit Sphagnum mosses and cotton grass (Eriophorum) cover at the expense of ling heather (Calluna vulgaris). We repeated an assessment from a Pennine study of post-burning vegetation succession at a moor in south-west Scotland also managed for grouse. Here, GPS-mapped fires from 2009 to 14 were visited in 2019 to measure the vegetation response and compare it with unburned control plots. Heather cover, vegetation height and biomass increased linearly over time since burning, whereas cotton grass decreased during the first eight years. Sphagnum cover in plots burnt eight to ten years earlier averaged five times higher than that in the no-burn control plots and was positively correlated with peat depth. These results support earlier studies in northern England, showing that prescribed burning at regular intervals can increase Sphagnum cover by reducing heather cover and canopy vegetation biomass. We discuss the repercussions of this for management of blanket peat habitat, including reducing wildfire risk across UK moorlands.

Killing of raptors on grouse moors: evidence and effects

Owing to the intensity of game management in Britain, managers of grouse moors have illegally killed raptors to increase the numbers of Red GrouseLagopus l. scoticaavailable for shooting. This paper summarizes evidence for the recent scale of illegal raptor killing on grouse moors and its effects on populations. It provides insights into how raptors themselves respond demographically to different levels of killing. Over Britain as a whole, most raptors have increased and expanded considerably since the 1970s, in response to reduced killing and nest destruction, and the diminished impacts of organo‐chlorine pesticides; however, in recent decades the populations of some species have declined on and around grouse moors. This is widely evident in Hen HarrierCircus cyaneus, Peregrine FalconFalco peregrinusand Golden EagleAquila chrysaetospopulations and in more restricted areas also in Northern GoshawkAccipiter gentilisand Red KiteMilvus milvuspopulations, in all of which illegal killing has been sufficient to affect numbers over wider areas. The evidence consists mainly of: (1) greater disappearance of nesting pairs, lower breeding densities or reduced occupancy of apparently suitable traditional territories on grouse moors compared with other areas; (2) reduced nest success compared with other areas; (3) reduced adult survival compared with other areas; (4) reduced age of first breeding, reflecting the removal of adults from nesting territories and their replacement by birds in immature plumage; (5) greater levels of disappearance of satellite‐tracked birds on grouse moors than elsewhere; and (6) the finding of poisoned baits and traps, and shot or poisoned carcasses of raptors. Not all these types of evidence are available for every species, and other types of evidence are available for some. The Common BuzzardButeo buteois currently the most numerous raptor in Britain and also seems to be killed in the greatest numbers. Other raptor species, including MerlinFalco columbarius, Common KestrelFalco tinnunculusand Eurasian SparrowhawkAccipiter nisuswhich nest on or near grouse moors, have little or no significant impact on grouse and are killed less often or not at all. In the absence of illegal killing, some raptor species breed as well or better on grouse moors than in other habitats. Merlins, in particular, seem to thrive on grouse moors, benefiting from the management involved (including predator control). Other aspects of illegal raptor killing are discussed, including suggestions for ways in which it might be reduced.

Distribution of mountain hares Lepus timidus in Scotland in 2016/2017 and changes relative to earlier surveys in 1995/1996 and 2006/2007

Mountain hares Lepus timidus, incorporating the subspecies L. t. varronis, L. t. hibernicus and L. t. scoticus, have declined in range throughout continental Europe where they face pressures from climate-change, competition and land-management. In Scotland, the absence of a national monitoring scheme, including mandatory reporting of hunting records, means that producing robust estimates of mountain hare population trends is difficult. We repeated questionnaire surveys conducted in 1995/1996 and 2006/2007 to assess the 2016/2017 distribution and hunting records of mountain hares in Scotland and describe regional changes in their distribution over a 20-year period in relation to management for red grouse Lagopus lagopus scotica shooting. Comparisons of areas covered in all surveys indicated no net change in the area of Scotland occupied by mountain hares, but within that we found changes in range between regions and sites of differing grouse management intensity. Between 1995/1996 and 2016/2017, range contractions in southern Scotland contrasted with no changes in north-–east Scotland. In north-west Scotland range expanded by 61% in areas practicing driven grouse shooting, declined by 57% in areas practicing walked-up grouse shooting and remained low and stable in areas which did not shoot grouse. A total of 33 582 mountain hares were killed in 2016/2017 representing a 71% and 48% increase from 1995/1996 and 2006/2007 respectively. However, the average kill density in 2016/2017 (12.4 ± 3.3 hares km–2) was comparable to 2006/2007 (10.8 ± 3.0 km–2) and we found no relationship between kill density and contractions in range. Despite increases in numbers of mountain hares killed over the last 20 years, it appears that range contraction may be attributed to factors other than culling, such as changes in habitat and management. Disentangling these factors should be the focus of future research.

Differential responses of heather and red grouse to long-term spatio-temporal variation in sheep grazing

During the last century, afforestation and intensification of sheep grazing in the British uplands have led to widespread declines in globally rare heather moorland. We quantified changes in heather cover over 70 years in relation to changes in sheep grazing on Langholm Moor, and examined the impact on red grouse, a gamebird inhabiting heather moorland. Between 1948 and 2009, when grazed heavily by sheep, heather-dominated vegetation declined from 53 to 14% cover. Large-scale sheep reductions from 2011 then allowed increase of heather-dominated vegetation cover to 18% by 2015. However, changes in heather cover were associated with changes in grouse abundance only where heather-dominated cover was reduced below thresholds of 27% (95% CL 18–36%; pre-breeding) and 17% (95% CL 13–20%; post-breeding). The number of grouse shot between 1951 and 1992 remained high where 37–65% of dominant heather cover was retained, but then declined between 1992 and 1996 following increased predation by raptors, leading to the cessation of shooting. Subsequently, grouse densities fluctuated in relation to periodic management by gamekeepers (1992–1999 and 2008–2016), but heather loss continued possibly until 2011, and predation in this context prevented sustained increases sufficient for ‘driven’ shooting. Grouse shooting provides an economic incentive to maintain and restore heather moorland. On Langholm Moor, however, afforestation in the surrounding landscape and isolation from other heather moors may have led to a grouse population less well buffered against growing predation pressure, especially outside keepered periods. As grouse shooting could not be restored, the future management of the moor remains uncertain.

Recreation conflict, coping, and satisfaction: Minnesota grouse hunters’ conflicts and coping response related to all-terrain vehicle users, hikers, and other hunters

Studying conflict and coping in recreation is important because some coping strategies may provoke distress, while others may lead to positive emotional changes. Building on applications of the transactional stress coping model to park visitors, anglers, and other recreation participants, we explored how Minnesota grouse hunters responded to interference by all-terrain vehicle (ATV)/off-highway vehicle (OHV) users, deer hunters, other grouse/bird hunters, general other hunters, hikers, and bear hunters. We examined relationships among interference, coping, and satisfaction for grouse hunters, and examined how hunter beliefs about ATV use related to perceptions of conflict with ATV users. Encounters with ATV users, deer hunters, other grouse hunters, and hikers lead to problem- and emotion-focused coping, including displacement, confrontive coping, and psychological distancing. Interpersonal conflict with ATVs was positively related to perceptions of interference from ATV users, while no/limited conflict was negatively related. Conflict and coping had a minimal effect on satisfaction. Management implicationsAlthough reported levels of interference from other user groups was relatively low, grouse hunters reported moderate interference from ATV users and the use of confrontive coping in response to interactions with ATV riders. Confrontive coping has been associated with increased distress, and deserves attention. However, interference from ATV users was low to moderate and most grouse hunters in the study personally use ATVs for recreation, so there is limited need for management to address conflicts between grouse hunters and ATV riders. Nevertheless, zoning for ATV-free grouse hunting could be tested in areas with reported conflicts between hunters and ATV riders.

Long-term changes in the abundance and breeding success of raptors and ravens in periods of varying management of a Scottish grouse moor

Management of heather moorland for driven Red Grouse (Lagopus lagopus scotica) shooting in the British uplands may benefit some raptors by reducing predation risk, especially when breeding, and by increasing food availability. We describe changes in abundance and breeding success of four raptor species and Common Raven (Corvus corax) during a 27-year study on a grouse moor in southwest Scotland in relation to whether or not the moor was managed by gamekeepers. Ground-nesting raptors, Hen Harrier (Circus cyaneus) and Merlin (Falco columbarius), increased during periods of grouse moor management and had a higher proportion of successful nesting attempts. Predation was the main apparent cause of breeding failure. In contrast, grouse moor management did not influence either abundance or breeding success of tree- and crag-nesting species, i.e., Peregrine (Falco peregrinus), Common Buzzard (Buteo buteo), and Raven. Buzzard sightings increased during the study, in line with their national recovery, whereas Peregrine and Raven showed little change in abundance. The results of our study highlight that management for Red Grouse can benefit both Hen Harrier and Merlin. However, on a UK scale these benefits to Hen Harriers, but not Merlin, are outweighed by their illegal killing, caused by fears that their consumption of Red Grouse can undermine the economics of grouse moor management.

Correlates of pathological lesions associated with respiratory cryptosporidiosis prevalence in shot red grouse Lagopus lagopus scotica from moors in northern England

ABSTRACT Infection of wild red grouse Lagopus lagopus scotica by Cryptosporidium baileyi was first diagnosed in 2010. Within three years, signs of infection were reported from grouse on half of all grouse moors in northern England, bringing severe concerns of economic losses to grouse shooting. A total of 45,914 red grouse shot from 10 moors in northern England between 2013 and 2018 were visually screened for signs of respiratory cryptosporidiosis. Prevalence varied with age, being twice as high in juveniles (4.5%) as in adults (2.4%). It also varied nine-fold between moors and three-fold between years. Prevalence was highest in grouse shot later in the shooting season. Our results are consistent with the concept that disease incidence is highest in naïve juveniles that have previously not been exposed to infection, with prevalence dropping as birds develop immunity. We found no evidence of increased prevalence over time, and fears of escalated disease prevalence, bringing with it increased mortality and lowered productivity, that may have significant impacts on the economic viability of shoots, have not yet been realized. We recommend continued annual screening for clinical signs amongst shot birds, better hygiene associated with potential reservoirs of infection, and practices that both improve the detection and selective culling of diseased individuals and generally reduce overall grouse densities.

The influence of different aspects of grouse moorland management on nontarget bird assemblages.

Conflict between stakeholders with opposing interests can hamper biodiversity conservation. When conflicts become entrenched, evidence from applied ecology can reveal new ways forward for their management. In particular, where disagreement exists over the efficacy or ethics of management actions, research clarifying the uncertain impacts of management on wildlife can move debates forwards to conciliation.Here, we explore a case‐study of entrenched conflict where uncertainty exists over the impacts of multiple management actions: namely, moorlands managed for the shooting of red grouse (willow ptarmigan) Lagopus lagopus in the United Kingdom (UK). Debate over how UK moorlands should be managed is increasingly polarized. We evaluate, for the first time at a regional scale, the relative impacts of two major moorland management practices—predator control and heather burning—on nontarget bird species of conservation concern.Birds were surveyed on 18 estates across Northern England and Southeast Scotland. Sites ranged from intensively managed grouse moors to moorland sites with no management for grouse shooting. We hypothesised that both targeted predator control and burning regimes would enhance ground‐nesting wader numbers and, as a consequence of this, and of increased grouse numbers, nontarget avian predators should also be more abundant on heavily managed sites.There were positive associations between predator control and the abundance of the three most widespread species of ground‐nesting wader: strong effects for European golden plover Pluvialis apricaria and Eurasian curlew Numenius arquata and, less strongly, for common snipe Gallinago gallinago. These effects saturated at low levels of predator control. Evidence for effects of burning was much weaker. We found no evidence of enhanced numbers of nontarget predators on heavily managed sites.

Metabarcoding-based dietary analysis of hen harrier (Circus cyaneus) in Great Britain using buccal swabs from chicks

The hen harrier is a heavily persecuted bird of prey in Great Britain since its diet includes Red grouse, a game bird shot in driven and walked-up grouse shooting. Unlike walked-up shooting where shooters walk up moors and flush grouse with dogs, in driven grouse shooting the grouse are driven by beaters towards static shooters. Driven grouse moors (DGMs) are increasingly being managed to sustain high densities of Red grouse intensifying a long-standing conservation conflict between conservationists and grouse moor keepers. A metabarcoding approach was used with degenerate universal cytochrome oxidase I and cytochrome b primers along with hen harrier blocking primers. A novel sampling method was used to detect prey in buccal swab samples from chicks from broods across Great Britain from both managed and unmanaged moorland habitats. This resulted in detection of 62 species of prey across 51 broods with Meadow pipit, Red grouse, Wren, Skylark, and voles being most frequently detected. Frequency of occurrence data and species accumulation curves reveal high incidence of Red grouse and low prey species richness in the diet of hen harriers in DGMs but low incidence of Red grouse and high prey species richness in walked-up and unmanaged moors. Waders were only detected within walked-up and unmanaged moors and not within DGMs where they have been reported to occur at high densities. Regional species detected included endemic species such as the Orkney vole seen only in Orkney. This study represents the first metabarcoding-based dietary analysis in a raptor using buccal swabs.

Measures of predator diet alone may underestimate the collective impact on prey: Common buzzard Buteo buteo consumption of economically important red grouse Lagopus lagopus scotica.

Human-wildlife conflicts often centre on economic loss caused by wildlife. Yet despite being a major issue for land-managers, estimating total prey losses to predation can be difficult. Estimating impacts of protected wildlife on economically important prey can also help management decisions to be evidence-led. The recovery in population and range of common buzzards Buteo buteo in Britain has brought them into conflict with some gamebird interests. However, the magnitude of any impact is poorly understood. We used bioenergetics models that combine measures of buzzard abundance from field surveys with diets assessed by using cameras at nests, prey remains and pellet analysis, to estimate their impact on red grouse Lagopus lagopus scotica on a large (115 km2) moor managed for red grouse shooting in Scotland. Whilst grouse consumption by individual buzzards was lower than previous estimates for other raptor species present on our study site, total consumption could be greater given an estimated 55–73 buzzards were present on the study site year-round. Averaging across diet assessment methods, consumption models estimated that during each of three breeding seasons (April-July 2011–2013), the buzzards foraging on our study site consumed 73–141 adult grouse and 77–185 chicks (depending on year). This represented 5–11% of adult grouse present in April (22–67% of estimated adult mortality) and 2–5% of chicks that hatched (3–9% of estimated chick mortality). During two non-breeding seasons (August-March), consumption models using pellet analysis estimated that buzzards ate a total of 242–400 grouse, equivalent to 7–11% of those present at the start of August and 14–33% of estimated grouse mortality during the non-breeding season. Buzzard consumption of grouse has the potential to lead to non-trivial economic loss to grouse managers, but only if buzzards predated the grouse they ate, and if grouse mortality is additive to other causes.

Assessing soil compaction and micro-topography impacts of alternative heather cutting as compared to burning as part of grouse moor management on blanket bog.

BackgroundOver 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).MethodsWe 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.ResultsDespite 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.DiscussionCutting 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.

Bog breathing: the extent of peat shrinkage and expansion on blanket bogs in relation to water table, heather management and dominant vegetation and its implications for carbon stock assessments

Peatlands represent a globally important carbon stock. Peat soil carbon stock assessments rely on measurements of carbon concentration, bulk density and soil depth. However, peat surface levels - and thus soil depths - change (“bog breathing”) largely as a response to peat shrinkage and expansion in relation to water table changes. This study assessed the magnitude of and potential for this mechanism to influence carbon stock calculations under field and laboratory conditions. In the UK, most peatlands are upland blanket bogs, of which a large proportion are managed as ‘grouse moors’. This currently involves rotational burning, although alternative management is increasingly considered. Peat depth and water tables were investigated on three grouse moors on blanket bog in northern England, comparing changes under different heather management interventions (burning, mowing and uncut). One site also allowed investigation of changes in relation to slope and under the three major bog vegetation types (ling heather, cottongrass and Sphagnum moss), which were compared to observed changes in peat cores under controlled laboratory conditions simulating periods of drought and rewetting. Changes in depth and bulk density were recorded and the potential implications for carbon stock estimates were calculated. Results highlight site specific relationships as potential habitat condition indicators and demonstrate that previously reported surface peat carbon losses resulting from enhanced decomposition under rising temperatures might also be explained by apparent changes due to peat shrinkage and expansion. It is recommended to accurately record bulk density and total peat depth measurements as part of peat carbon stock assessments.