1. Testing conservation management interventions helps to diagnose causes of biodiversity loss and identify practical solutions, so helping to build a robust evidence base for good conservation decision-making. 2. The Royal Society for the Protection of Birds (RSPB) has multi-decadal experience of collaboration between scientists and practitioners to inform conservation. This is based on a problem-solving framework to identify, test and adaptively improve interventions for species and ecosystem recovery, using RSPB's nature reserves, landscape-scale conservation and agri-environment interventions as platforms. Here, we draw upon our experience of experimental tests and related counterfactual study designs, addressing conservation management problems at multiple scales, to consider the benefits and challenges involved in deploying these approaches and some of the insights gained. 3. Outcomes with tangible conservation impact required enduring trust and partnership between scientists, conservation practitioners and funders, both within and between organisations. Challenges have most often arisen when it is difficult to introduce and maintain experimental designs in the face of wider land management priorities and pressures, and when biological understanding of what works has not been matched by social and economic understanding of what measures will be practicable and attractive for those responsible for implementation. 4. Synthesis and applications. Tests of conservation interventions, and especially long-term experiments, are most likely to succeed when there is a broad partnership commitment to evidence-based approaches amongst practitioners and funders, as well as scientists. A track record of implementing such studies has undoubtedly helped to build organisational capability in evidence-based conservation in RSPB but more remains to be done to fully embed a culture of evidence-based planning, decision-making and conservation action. Nonetheless, our examples suggest that effort invested in building evidence-based capability in conservation organisations will be repaid because it acts to optimise conservation impact. It also builds the knowledge and confidence of scientists and practitioners to act as honest brokers and advocates at the interface between science, practice and policy to drive conservation impact at a time of unprecedented environmental challenge.

Protected areas (PAs) and agri‐environment schemes (AESs) are the main policy mechanisms for addressing terrestrial biodiversity loss in Europe. Landscape context can moderate their efficacy but has not been studied for both mechanisms concurrently. Both mechanisms are widely used to address ongoing declines of waders breeding on lowland wet grassland. Using a repeat, nationwide (England) survey, we investigate the role of PA status (nature reserves and a statutory designation), AES (bespoke and general options), surrounding landcover (up to 1500 m), soil properties and range position (core vs. periphery) on field‐level breeding occupancy and abundance change of four declining waders between 2009/2010 and 2020/2021. Field occupancy of Northern Lapwing Vanellus vanellus , Common Redshank Tringa totanus and Common Snipe Gallingo gallinago was associated with PA status, being highest in reserves. Abundance change was more positive on fields in reserves than in unprotected or designated non‐reserve sites for Lapwing, Redshank and Eurasian Curlew Numenius arquata . Fields under bespoke wader AES management were more likely to hold Lapwing and Redshank, which could reflect local redistribution or effective option targeting. Although there was limited evidence that AES increased wader abundance, habitat maintenance options within and outside PAs maintained, and habitat creation/restoration options within reserves increased, Lapwing and Redshank abundance. Fields surrounded by more wet grassland were more likely to be occupied by Lapwing and Curlew, particularly in designated non‐reserve sites (Curlew only) and reserves. The same was true for Redshank and Snipe, but only in designated non‐reserve sites (Snipe only) and reserves. For Lapwing and Redshank, abundance change was more positive where surrounding wet grassland cover was greater. Synthesis and applications . Landscape context strongly moderates PA efficacy for breeding waders, with reserve fields performing particularly well when surrounded by favourable habitat. Further work is needed to establish the mechanism(s) behind these findings, but future conservation investment might prioritise expanding existing reserves, or the creation of large, new blocks with reserve‐level management. Future deployment of wader AES outside of reserves could focus on population maintenance, but to increase abundance schemes need to deliver higher habitat quality at sufficient scale.

CapsuleField plots provisioned with a supplementary seed mix during summer attracted European Turtle Doves and other farmland birds, and exhibited only a low incidence of the parasite Trichomonas gallinae.AimsTo test whether Turtle Doves and other granivorous birds use field plots provided with supplementary seed, and whether use of these plots increased exposure to T. gallinae.MethodsSupplementary seed mix was provided at two rates (3 and 6 kg per 250 m2 plot) weekly at 37 sites in the spring and summer of 2016 and 2017. Provisioned plots, and similar (but unprovisioned) control areas, were surveyed for Turtle Doves and other birds. Soil swab samples were also taken and analysed for the presence of T. gallinae using a standard polymerase chain reaction procedure.ResultsTurtle Doves were much more likely to be recorded on provisioned plots than on unprovisioned control areas. Maximum counts of an aggregate of seven other granivores of conservation interest (European Greenfinch Chloris chloris, Common Linnet Linaria cannabina, Eurasian Tree Sparrow Passer montanus, House Sparrow P. domesticus, Common Reed Bunting Emberiza schoeniclus, Corn Bunting E. calandra and Yellowhammer E. citrinella) were significantly higher on provisioned plots than on control areas. Positive samples for T. gallinae were rare on provisioned plots and unprovisioned areas (eight of 474 samples across both years). Samples classified as ambiguous (due to the presence of genomic DNA that could not be definitively ascribed to T. gallinae) or positive were equally likely on provisioned plots and unprovisioned areas, but were more likely at sites where European Greenfinches were recorded.ConclusionSupplementary seed provisioning in summer can attract foraging Turtle Doves with only a low risk of exposure to T. gallinae on the feeding areas.

Most demographic studies of multi-brooded species require information on breeding success per nesting attempt and the number of nesting attempts made to derive a measure of whole-season productivity. However, measuring the number of nesting attempts is often challenging. We used individual-based re-nesting models to estimate whole-season productivity for the Spotted Flycatcher Muscicapa striata in England to investigate demographic drivers of long-term population decline. Between 2004 and 2006 we monitored 248 nests in two regions of England covering three broad nesting habitats: farmland, garden and woodland. We combined field-derived measures of nesting start date, clutch size, hatching and fledging rates, whole-nest survival and re-nesting intervals, with nest-stage durations taken from the literature, to estimate whole-season per-pair productivity for each habitat and region combination. We weighted these estimates by the proportion of Spotted Flycatchers counted in each region-habitat (derived from extensive monitoring data for 1994-2006 and 2007-2021) to derive region-specific productivity measures. Finally, we compared these derived empirical productivity measures with the level required to maintain population size given current knowledge of survival rates of UK-breeding Spotted Flycatchers. Whole-season productivity only reached the required threshold for population stability in gardens. Regional estimates of whole-season productivity were substantially lower than the level required for population stability in both regions and both time periods, and the number of nesting attempts needed to achieve stability was also implausibly high in both regions. Assuming the same rates of whole-season productivity for Spotted Flycatchers distributed across these habitats and regions based on Breeding Bird Survey data for 2007-2021, productivity declined further to levels below that needed to sustain the population in all three habitats, mainly as a consequence of lower proportions recorded in gardens in southwest England. Historical and recent population declines of Spotted Flycatchers in eastern and southwest England are likely to have been caused by low productivity, particularly low survival of nests at the egg stage. Our study illustrates the utility of re-nesting models as a tool for understanding the demographic drivers of population change in multi-brooded species.

Knowledge of seasonal variation in hunting pressure and the demographic composition of hunting bags is likely to be important for the effective management of quarry species. Such knowledge is particularly important where regulatory mechanisms aim to avoid the over-exploitation of quarry species having unfavourable conservation status. We compiled information on the age composition of harvested European Turtle-doves (Streptopelia turtur), and the daily numbers of doves shot and retrieved from 68 hunting estates spread across four Spanish regions. We use these data to describe temporal variation, and identify factors affecting daily hunting bags, age composition and crippling losses. We found that more juvenile doves were hunted than adults (and more than expected in a stable population) especially at the beginning of the hunting season, suggesting greater vulnerability of juveniles to hunting. The number of doves hunted each day declined through the hunting season and increased with the number of hunters present. Crippling losses averaged 9.6 % of all doves shot; applying this rate to recent Spanish government hunting statistics suggests under-recording of approximately 90,000 doves annually for the entire country. Our data on age composition and crippling losses can serve as direct inputs into future models of sustainable harvest for Turtle Dove in Europe. Our results highlight the importance of improving knowledge about the variables influencing take at the hunting event level for designing more efficiency regulatory measures.

Agri-environment schemes (AES) are the primary policy mechanism for addressing farmland biodiversity declines across Europe. Despite previous studies on the impacts of AES on biodiversity, there is little empirical evidence on the scale of provision required to reverse declines.Across three regions of lowland England with contrasting farm systems (arable, pastoral, mixed), we estimated avian population growth rates (PGRs) on farmland with high AES provision ('higher-tier': average bird-friendly option cover = 7.4%), low AES provision ('lower-tier': 2.3%) and no bird-friendly AES ('no AES'). Ten-year PGRs were derived for 24 species and three multi-species groups comprising farmland-associated species ('farmland birds'), species of conservation concern ('priority birds') and species restricted to farmland ('specialist birds'). We used PGRs to simulate the proportion of the regional farmland landscape that would have to be assigned to higher- and lower-tier agreements to stabilise or increase populations.In the arable and pastoral regions, 13/23 and 13/22 species, respectively, had more positive PGRs under higher-tier AES than on no AES farmland (none had more negative PGRs), compared to 4/22 (positive) and 1/22 (negative) in the mixed region. Only two to four species per region exhibited more positive PGRs under lower-tier AES compared to no AES farmland.Multi-species PGRs in the arable and pastoral regions increased from no AES (strong decline), to lower-tier (decline or stability) to higher-tier (moderate or strong increase). There was no overall AES effect in the mixed region. To increase regional farmland bird populations by 10% over 10 years, 47% and 26% of the farmed landscape would need to be devoted to higher-tier agreements in arable and pastoral landscapes respectively. This falls to 34% and 17% when higher-tier is targeted at localities supporting higher abundances of target species, and to 29% and 10% when 30% of the farmed landscape is also devoted to lower-tier. Priority and specialist birds require higher provision levels. Policy implications. Where farmland bird recovery is an AES objective, farms should prioritise higher-tier agreement delivery over lower-tier. Farmland bird responses to AES provision are likely to vary regionally, but careful targeting will reduce the amount needed in the landscape.

Finite land is under pressure to provide food, timber, human infrastructure, climate change mitigation, and wildlife habitat. Given the inherent trade-offs associated with land-use choices, there is a need to assess how alternative land-use trajectories will impact the delivery of these benefits. Here, we develop nine exploratory, climate change mitigation-driven land-use scenarios for the UK. The scenario that maximized deployment of nature-based solutions reduced greenhouse gas (CO2e) emissions from the land sector by >100% by 2050 but resulted in a 21% decline in food production. All mitigation scenarios delivered aggregate increases in habitat availability for 109 bird species (including 61 species of conservation concern), although farmland-associated species lost habitat. Our study reiterates the potential of nature-based solutions to address global climate and biodiversity challenges but also highlights risks to farmland wildlife and the importance of food system reform to mitigate potential reductions in primary food production.

In common with many other insectivorous birds, the Common Swift Apus apus is undergoing population declines, with an estimated 57% reduction in abundance between 1995 and 2017 in the UK. The ultimate drivers of this decline are poorly understood but links have been drawn to reductions in the abundance and availability of insect prey, as well as loss of nesting sites. The aim of this study is to improve understanding of the demographic and environmental drivers of Swift decline in Great Britain, with a particular focus on weather and aphid biomass. We explore spatio‐temporal trends in the biomass of aphids, an important source of food for these aerial feeders, from a network of 17 suction‐traps, each 12.2 m in length. We then use data from national nest recording and ringing schemes to describe temporal trends in, and covariates of, Swift breeding success and annual survival. Demographic data are sparse prior to the mid‐1990s but show stable adult survival, a reduction in first‐year survival and an increase in nest failure rate since the mid‐1970s. Despite marked declines in aphid biomass across much of southern and eastern England during this period, we find no association between aphid biomass and Swift demography. Weather was a stronger correlate of variation in Swift demography, with increased precipitation associated with smaller brood size, higher nest failure rate and lower first‐year survival. Our data suggest that falling first‐year survival, partly linked to wetter summers, may be the most likely demographic driver of population decline. Given that the only convincing correlates of Swift demography were weather‐related, we suggest it would be precautionary for conservation efforts to continue to focus on ensuring that safe and productive nesting sites are in sufficient supply. Further research to identify habitats and land management practices which provide foraging resources, particularly during periods of inclement weather, is required, and future demographic modelling exercises would benefit from increased nest recording and ringing efforts.

Ground-nesting birds such as breeding waders are of high conservation concern throughout Europe, experiencing population declines driven by agricultural intensification and low breeding success often caused by predation. One mechanism for encouraging wader recovery outside of nature reserves is Agri-Environment Schemes (AES), where financial incentives encourage farmers to improve their land management practices to promote wildlife and ecosystem services. The effectiveness of such schemes for waders outside of nature reserves is limited however. Methods for improving delivery of conservation action in the wider countryside are therefore urgently needed. Here we evaluate the effectiveness of the Halting Environmental Loss Project (HELP), where site-specific advice, training and practical assistance in conducting breeding wader habitat management were provided at a range of upland and lowland sites across Northern Ireland. HELP did not provide direct financial incentives to landowners, instead, targeted advice and access to specialist machinery and expertise were provided to stimulate habitat management interventions and enhance existing wader conservation measures (AES or reserve funding). Benefits were observed both on and off reserves, although the quality and extent of the habitat management undertaken was generally higher on reserves. Temporal trends in breeding densities were more positive for three wader species during HELP than previously and continued to be positive for a fourth species. Our results demonstrate that targeted advice and practical assistance can lead to improvements in habitat management and subsequent increases in wader breeding densities inside and outside nature reserves. Future wader conservation projects are likely to be most effective when expert advice is deployed in combination with other mechanisms to fund management such as nature reserves or AES payments, and in many situations reductions in predation pressure will also be needed.

Nature recovery actions within anthropogenic landscapes typically target small and unrepresentative species subsets, or generic habitat features that are assumed to benefit wider suites of species, despite incomplete understanding of what these species are, or of their autecological needs. These limitations in the evidence underpinning conservation contribute to continuing biodiversity losses.Experimental evidence shows improved outcomes follow the use of spatially-targeted audits of multi-taxa biodiversity information, allowing actions to be tailored towards the ecological requirements of complete local species pools. We illustrate how this approach could be integrated into environmental policy, with particular reference to the European Union's 2030 Biodiversity Strategy and the UK Environment Act 2021's Local Nature Recovery Strategies (LNRS).Biodiversity auditing uses existing repositories of species occurrence and functional trait data to group priority species into cross-taxa 'management guilds' that share similar responses to conservation interventions, allowing practitioners to identify and implement regionally-optimized, evidence-based action plans. Where previously implemented, this approach has successfully transformed conservation practices at bioregional scales, increasing the richness and abundance of priority species relative to pre-existing management.We provide methods for incorporating rapid low-cost biodiversity auditing into local conservation strategies, to ensure these support the widest complement of priority biodiversity. Failure to adopt a data-driven approach risks reproducing previously ineffective paradigms, and thus failing to seize vital chances to reverse declines in biodiversity. We further argue that researchers should prioritize the development of accessible tools to support authorities to incorporate species data into strategic landscape-scale conservation design.

Agri-environment incentives form a central mechanism supporting changes to land management to provide public benefits. This study assesses the medium-term effects of woodland management on 13 target, specialist woodland bird species, as well as other woodland birds in a single region of the UK. The abundance of breeding birds (using two methods: point counts and territory mapping) and metrics of woodland structure were recorded on sites with Woodland Improvement Grants (improvement sites) and nearby comparison sites (control sites). Initial measurements were made prior to management and repeated 7-9 years later. A separate comparison of changes in bird abundance was made between the managed woodland sites and woodland from similar landscapes surveyed as part of the national Breeding Bird Survey (BBS). There was an increase in abundance of target species on improvement sites compared to a decrease on both control sites and BBS sites, although this was only evident from point count data. The effects on target species were stronger than for other woodland specialists and there was no apparent effect on woodland generalists, suggesting that the management interventions were appropriate for the target species. Changes in woodland structure were generally consistent with the expected effect of management, with lower tree density and greater Bramble (Rubus sp.) cover. However, contrary to the aim of increasing understorey cover, a reduction was recorded within the 2-10 m height category in improvement sites. This contrast is due to the removal of young trees during thinning affecting this height band and the short time period since management to allow regrowth. Our findings show that bespoke management supported through government agri-environment incentives can have a positive impact on target woodland birds. For managed forests, identifying species requirements and how management can be adapted to improve their habitats can be an effective way of delivering biodiversity gains when financial incentives are provided to achieve policy goals.

Designing evidence-based policies that regulate harvest levels is essential to avoid unsustainable hunting. This requires a good understanding of the relationship between bag sizes and regulatory mechanisms of harvest, and particularly of how these mechanisms are implemented locally and how they vary between game estates. The European Turtle-dove (Streptopelia turtur) has decreased by 30–49% since the late 1990s. The three main identified threats for the species are habitat loss, illegal killing and unsustainable legal hunting. We assessed how turtle dove estate-level harvest varies in relation to hunter density, number of hunting days, the adopted hunting method, game management intensity and the economic investment of the estate. Additionally, we assessed whether estate-level harvest had declined concomitantly with the population decline, and whether trends had been similar in relation to hunting method. We analysed Hunting Management Plans and Annual Hunting Reports of several thousand estates in central Spain, one of the main breeding and hunting areas of the species. Annual estate harvest was positively associated with hunter density, and was higher on estates that offered fixed-position hunting compared to those that only provided walked-up shooting. Importantly, these decisions are made by managers at the estate level and are not directly regulated by policy. We also found that more turtle doves are harvested on estates that invest more money in management, suggesting that the socioeconomic characteristics of the estate also influence local decisions on harvest intensity. Average annual estate-level harvest declined by 27% between 2007 and 2018, accompanied by a switch from fixed-position to walked-up hunting practices. Our study indicates that reducing hunting density or the number of fixed-position hunting days may be the most efficient ways to reduce turtle dove harvest, and that factors influencing estate-level decision-making have to be understood if reduction of hunting pressure in declining species is sought.

Wildlife management regulations for exploited species often aim to manipulate harvest levels in order to avoid unsustainable levels of exploitation. For such regulations to be effective the size of the harvest needs to respond to changes in those regulatory measures. The European turtle-dove is a widespread migratory quarry species of conservation concern for which recent levels of hunting in Western Europe are considered unsustainable. We describe temporal and spatial variation in the hunting of this species across Spain, the country with the largest harvest in Europe, after reducing biases inherent in the official Government statistics. We also assess whether changes in hunting policy regulations (the number of permitted hunting days, the start date of the hunting season and daily quotas imposed on hunters) have been effective in limiting the numbers of turtle doves harvested. Official national government harvest statistics under-estimated harvest reported by hunters by an average of 38% during 2007–2009 due to information gaps and underreporting, but this problem subsequently declined and was negligible by 2017. The density of shot birds was highest in the southwest of the country. None of the three regulatory measures had any detectable impact on reported provincial harvest, indicating that the main policy mechanisms employed by the Spanish hunting authorities to manage hunting have been ineffective. Our findings highlight the continued need of accurate measures of harvest and of developing and deploying effective means of managing the harvest of quarry species, especially those with unfavorable conservation status.

Understanding how to allocate land for the sustainable delivery of multiple, competing objectives is a major societal challenge. The land sharing-sparing framework presents a heuristic for understanding the trade-off between food production and biodiversity conservation by comparing region-wide land-use scenarios which are equivalent in terms of overall food production. Here, for two contrasting regions of lowland England (The Fens and Salisbury Plain), we use empirical data and predictive models to compare a suite of spatially explicit scenarios reflecting the full range of the sharing-sparing continuum, including mixed scenarios which combine elements of both sharing and sparing. We evaluate a range of outcomes (bird populations, global warming potential (GWP), nitrogen and phosphorus pollution and outdoor recreation), to identify approaches to regional land-use planning with the potential to deliver multiple societal benefits. Land-sharing scenarios (which reduce the dominance of productive agricultural land in farmed areas and the area of larger unfarmed areas) result in negative outcomes, particularly for birds and GWP. In contrast, many land-sparing scenarios (including mixed scenarios which increase the area of lower-yield farmland alongside larger unfarmed areas) resulted in improvements in all or most outcomes, although for recreation and nutrient export differences between scenarios were modest. Importantly, environmental outcomes also depended on the spatial arrangement of spared land, the types of natural or semi-natural habitat promoted on spared land, whether some lower-yield farmland is delivered alongside larger unfarmed areas, and the overall region-wide food production target. Policy implications. Our study suggests that land-sparing strategies which increase the area of natural and semi-natural areas can improve environmental outcomes, despite the costs associated with high-yield agriculture. However, high-yield agriculture should not compromise future production or the conservation value of spared land, and explicit policies such as certification or payments for ecosystem services are required to link sustainable high-yield production to habitat conservation. Our study also highlights the importance of mitigating projected increases in food demand.

Aim To describe the population trend for European turtle doves in Spain. To identify favourable and unfavourable areas for the species and to test whether favourability or land use explain spatial variation in abundance change. Location Mainland Spain. Methods We used generalized linear models with extensive abundance data to describe population change for the European turtle dove across Spain. We used breeding distribution (presence/absence) data at 100 km(2) resolution to model environmental favourability in relation to topo-climatic and land use variables. Finally, we tested whether land use and favourability explained spatial variation in abundance trends. Results The large Spanish turtle dove population declined by 37% between 1996 and 2018. Favourability was highest in the south, east and north-west of Spain and lowest in the north and at higher altitudes. Abundance trends were more negative in areas of lower environmental favourability and in localities dominated by arboreal habitats such as forests, "dehesas" (open agro-forestry landscapes with scattered Quercus trees), transitional woodland shrubs or sclerophyllous vegetation (a mixture of sclerophyllous shrubs with some scattered trees). Trends were more positive in localities dominated by complex cultivation (small parcels of mixed crop types, including woody permanent crops like olive, almond trees or vineyards). Main conclusions Our study highlights a substantial recent decline in the numerically important turtle dove breeding population in Spain. Declines in abundance were more strongly associated with arboreal (forest and shrub areas) rather than agricultural habitats, highlighting an urgent need for further research into the ecology of this important quarry species in arboreal breeding habitats in southern Europe.

Since neonicotinoid insecticides were introduced to the agricultural market, evidence of the negative impacts of these systemic compounds on non-target species has accumulated. Birds are one of the largest groups of species to inhabit farmland, but the extent of neonicotinoid exposure in avian communities is poorly understood and very little is known about how any exposure may affect wild birds. Here, free-living gamebirds were used as a model group to measure the extent of avian exposure to the neonicotinoid dothianidin via seed treatment. During a typical sowing period of winter cereals treated with clothianidin, blood and liver samples were collected simultaneously from individual hunted gamebird carcasses, both pre- (n = 18) and post-sowing (n = 57) and were analysed for dothianidin via LC/MS-MS. Body weight, fat score and faecal parasite load were also quantified in the birds to ascertain whether any of these health parameters were associated with clothianidin exposure under field conditions. Clothianidin was detected in 6% of individuals sampled pre-sowing and 89% of individuals sampled post-sowing. The frequency of dothianidin detection in plasma samples and the concentration of dothianidin in liver and plasma samples decreased significantly between the first week and 2-4 weeks post-sowing. Faecal parasite load was positively associated with concentrations of clothianidin in the liver (but not plasma) of partridge species, but there was no association between clothianidin concentration and fat score or body weight, for either sample type. This study provides clear evidence that treated seed is a source of pesticide exposure for gamebirds following autumn sowing. These findings have implications for gamebirds worldwide where seed treatments are in use, and will aid the design of any future avian biomonitoring studies for agrochemical compounds. (C) 2020 The Authors. Published by Elsevier B.V.

The land sharing-sparing framework aims to quantify the trade-off between food production and biodiversity conservation, but it has been criticized for offering, for reasons of simplicity, an unrealistically limited set of different land uses. Here, we develop the framework to evaluate a much larger suite of land-use strategies in which the areas and yields of three land-use compartments - natural habitat, high-yield farmland, and lower-yield farmland - are varied simultaneously. For two regions of England, we use functions that relate the local population density of breeding bird species to farm yield to simulate species-specific region-wide population sizes under each strategy. We find that geometric mean population size, averaged across all species, is maximized when farmland yields are higher than the current average yield, and when spared land combines both natural habitat and low-yield farmland. This conclusion is relatively insensitive to the maximum yield considered feasible under extreme land sparing, and holds across a range of region-wide food production targets. To some extent, our conclusion depends on which species groups were included in the assessment. Considered alone, farmland birds preferred a strategy with little or no natural habitat. Nonetheless, the optimal strategy was broadly consistent across all widely recognized listings of species of conservation concern. Synthesis and applications. Our study looks at landscapes with a long history of agricultural use, and which have little remaining natural habitat, such as those found in lowland England. In these landscapes, conservation outcomes are likely to be maximized by mixed strategies in which high-yield production enables an increase in area of both natural habitat and low-yield farmland elsewhere in the region.

SummaryWith a decline exceeding 30% over three generations, the once-common European Turtle-dove is now considered globally threatened by IUCN. As a legal game species in 10 European countries, the recent International Single Species Action Plan for this species highlighted the need to carry out an assessment of the sustainability of current levels of hunting. In 2013–2014, the Western European population was estimated at 1.3–2.1 million pairs, and the hunting bag in the same region to be 1.1 million birds. Using the Demographic Invariant Method, we assessed whether current levels of hunting harvest within Europe constitute overexploitation of the western flyway European Turtle-dove population. We calculated the maximum growth rate λmax that a population might achieve in the absence of any additive mortality. Then we estimated the potential maximum harvestable population fraction (P) allowed by excess population growth. We explored a wide range of plausible scenarios relating to assumed demographic rates, geographic scope of the flyway and management objectives. λmax was estimated to lie between 1.551 and 1.869. Current levels of hunting along the western flyway are more than double the sustainable fraction (P) under all suitably conservative scenarios, and only fall below this threshold under the most restrictive assumptions. We conclude that current levels of legal hunting along the western flyway are unlikely to be sustainable. Reducing uncertainty associated with assessments of the sustainability of turtle dove hunting will require improved information on (in order of decreasing importance) current levels of hunting, adult survival, age structure and population size.

Agriculture is a major driver of biodiversity loss and environmental degradation, so understanding how to reconcile food production with the maintenance of biodiversity and ecosystem services presents a critical challenge. The land sharing-sparing framework provides a heuristic approach for evaluating the environmental consequences of contrasting regional scenarios which – crucially – produce an equal quantity of agricultural produce. Empirical evidence collected for several taxa across several regions of the world suggest that more species would benefit from land sparing (in which the extent of farmland is minimised through high-yield farming) than from land sharing (in which the extent of farmland is maximised through lower-yield farming). Our recent research on birds in two regions of lowland England supports a mixed, ‘three-compartment sparing’ strategy, in which high-yield farming spares land for both seminatural habitat and low-yield farmland. In this report, we first extend our work in The Fens and Salisbury Plain to consider spatially-explicit land-use scenarios, for which we quantify breeding bird population size, global warming potential (GWP), and nitrogen (N) and phosphorus (P) export. Second, we explore the sensitivity of our results to different species prioritisations. Third, we replicate our original analysis in two new regions (The Cotswolds and Low Weald), for butterflies as well as birds. For birds in The Fens and Salisbury Plain, our spatially-explicit scenarios reinforce our original conclusions, providing support for intermediate–extreme land sparing or three-compartment sparing. Land-sparing strategies also reduced GWP …