Simon R. Wotton

Countryside stewardship delivers cirl buntings (Emberiza cirlus) in Devon, UK

Enhancement of farmland biodiversity is a key objective of agri-environment schemes in Europe, and conservation of the rare and threatened cirl bunting (Emberiza cirlus) has been a key objective for the Countryside Stewardship Scheme (CSS) in south Devon, UK. Cirl bunting numbers increased by 83% on land entering CSS management agreements between 1992 and 1998, compared with an increase of just 2% on adjacent countryside not managed under CSS. The increase in cirl buntings on stewardship land was part of a wider regional increase in abundance rather than a redistribution of birds away from land not under stewardship. In 1998, 22% of all UK cirl buntings were breeding on land under CSS agreements and a further 16% of birds were within 0.5 km of land under stewardship. All but one of the 27 agreements that gained cirl buntings were within 2 km of cirl bunting breeding sites in 1992, with more distant agreements failing to be colonised even if they offered a range of potentially beneficial prescriptions. Agreements providing grass margins around arable fields, weedy winter stubbles and open patches of grassland next to scrub tended to gain additional cirl buntings. Grass margins and weedy winter stubbles constitute important food-rich habitats for cirl buntings and other farmland birds, and should be encouraged in future agri-environment agreements and schemes.

Changes in the numbers of breeding waders on lowland wet grasslands in England and Wales between 1982 and 2002

Capsule Lapwing, Snipe, Curlew and Redshank decreased significantly between 1982 and 2002, while over the same period Oystercatcher increased. Aims To provide current status and population trends for waders breeding on lowland wet grassland in England and Wales. Methods Waders were counted and mapped on three visits to 1051 lowland wet grassland sites, between April and June 2002. Data were compared with those gathered using identical methods in a survey in 1982 and related to land use characteristics and conservation designation. Results Between 1982 and 2002 there were significant declines of 38% for Lapwing Vanellus vanellus, 61% for Snipe Gallinago gallinago, 40% for Curlew Numenius arquata and 29% for Redshank Tringa totanus. Oystercatcher Haematopus ostralegus increased significantly by 47% in the same period. Populations of all species were highly aggregated with most of the birds found on a small number of key sites. Site designation was found to be an important predictor of breeding wader distribution, density and density change. Conclusions The marked population declines of four grassland wader species over the last 20 years are of considerable concern. Careful management of nature reserves and other key sites is essential to halt these declines, while wider scale and more carefully targeted agri-environment schemes may hold the key to reversing declines in the longer term. The efficacy of site designation and current agri-environment schemes for conserving breeding waders on wet grasslands needs to be reviewed.

The status of breeding Woodlarks Lullula arborea in Britain in 2006

Capsule There have been marked increases (88%) in the breeding population and breeding range (46%) of Woodlarks in Britain between 1997 and 2006. Aims To provide an accurate assessment of the population and distribution of Woodlarks in Britain and how these have changed since a survey conducted in 1997. Methods Survey coverage included ‘core’ 1 km squares (known occupancy in 1997) and a stratified random sample, based on suitable habitat and soil type. Results A population estimate of 3064 territories was obtained, giving an increase of 88% since 1997, while the range of occupied 10 km squares had increased by 46%. The majority of territories were associated with two main habitat types; heathland (66.7%) and forestry plantation (32.4%), and farmland in the southwest (13.4%). Sandy soils held the majority of territories (80.3%). Conclusion In the UK, the Woodlark is a species of high to moderate conservation concern subject to a national Biodiversity Action Plan (BAP). This survey demonstrated that the population has increased to meet the BAP targets set in 1996 for population size and range expansions in England, and is on schedule to meet targets in Wales. The species has responded to conservation restoration projects and is highly dependent on forest management.

Correlates of the change in Ring Ouzel Turdus torquatus abundance in Scotland from 1988–91 to 1999

CapsuleThe change was correlated with environmental, habitat and management variables. Aims To identify factors correlated with a population decline and range contraction between 1988–91 and 1999. Methods Regression models are used to describe the variation in Ring Ouzel abundance in 1988–91, and the change in Ring Ouzel abundance between 1988–91 and 1999. Results The abundance of Ring Ouzels in 1988–91 was negatively correlated with improved pasture, but positively with heather/smooth grass mosaic and Nardus/Molinia grassland. There was also a positive quadratic correlation with rock cover. A decline in Ring Ouzels between 1988–91 and 1999 was most likely on tetrads with shallow gradients, and outside of a 350–750 m altitudinal range. The change in ouzel numbers was also negatively correlated with both the initial area of conifer forest and heather/smooth grass mosaic. The rate of loss was greatest in those areas with a low Ring Ouzel abundance in 1988–91, although this effect was non-significant once habitat was accounted for. Conclusions The abundance of Ring Ouzels was linked to heather–grass mosaics, while declines were greater in tetrads lacking topographical features known to be selected by nesting ouzels. The negative relationship between forestry and population change suggests that large-scale afforestation of the uplands is a cause of concern.

Agricultural Management and Climatic Change Are the Major Drivers of Biodiversity Change in the UK.

Action to reduce anthropogenic impact on the environment and species within it will be most effective when targeted towards activities that have the greatest impact on biodiversity. To do this effectively we need to better understand the relative importance of different activities and how they drive changes in species’ populations. Here, we present a novel, flexible framework that reviews evidence for the relative importance of these drivers of change and uses it to explain recent alterations in species’ populations. We review drivers of change across four hundred species sampled from a broad range of taxonomic groups in the UK. We found that species’ population change (~1970–2012) has been most strongly impacted by intensive management of agricultural land and by climatic change. The impact of the former was primarily deleterious, whereas the impact of climatic change to date has been more mixed. Findings were similar across the three major taxonomic groups assessed (insects, vascular plants and vertebrates). In general, the way a habitat was managed had a greater impact than changes in its extent, which accords with the relatively small changes in the areas occupied by different habitats during our study period, compared to substantial changes in habitat management. Of the drivers classified as conservation measures, low-intensity management of agricultural land and habitat creation had the greatest impact. Our framework could be used to assess the relative importance of drivers at a range of scales to better inform our policy and management decisions. Furthermore, by scoring the quality of evidence, this framework helps us identify research gaps and needs.

Breeding status of the Red Kite Milvus milvus in Britain in 2000

Capsule The first co-ordinated Red Kite survey across Britain since the reintroduction programme began in 1989, yields 430 breeding pairs. Aims To estimate the current size and extent of the British breeding population. Methods A complete census of the populations in the East Midlands, Yorkshire, central and north Scotland was undertaken, while in Wales and the Chilterns, populations were surveyed using a stratified sample of tetrads. Breeding and territorial pairs were identified. Results The survey indicated that there were 430 breeding pairs in Britain (95% CIs, 372–490). There were 259 breeding pairs in Wales (95% CIs, 200–318) and 109 (95% CIs, 96–124) in the Chilterns. Elsewhere, 16 breeding pairs were located in the East Midlands, three in Yorkshire, seven in central Scotland and 33 in north Scotland. An additional three pairs were recorded in southern England, away from the main population centres. Conclusion The 2000 survey provides a baseline against which to measure future changes in Red Kite populations in Britain, using standard, repeatable methods.

The breeding status of the Ring Ouzel Turdus torquatus in the UK in 1999

Capsule The first co-ordinated census of breeding Ring Ouzels across the UK reports a minimum of 6157 (95% CI, 3586–9372) and a maximum of 7549 (95% CI, 4459–11197) territories. Aims To set a baseline for the future monitoring of breeding Ring Ouzels and to provide a systematically based estimate of the population size. Methods A random sample of tetrads (2 × 2 km squares) was surveyed from the known breeding range (as defined from the two national breeding bird atlases of 1968–72 and 1988–91). The survey method used tape playback and observation and involved walking four parallel transects in each tetrad. Results Tape playback accounted for one-third of the territories located. Of the tetrads surveyed that were known to be occupied during the 1988–91 breeding bird atlas, 39–43% were unoccupied in 1999. Conclusion The survey highlights a continuing contraction in range.

The status of breeding WoodlarksLullula arboreain Britain in 1997

We report on the 1997 national Woodlark survey which was organized by the Royal Society for the Protection of Birds, the British Trust for Ornithology and English Nature. In 1997, between 1426 and 1552 Woodlark territories were located in Britain. There has been a considerable increase in the population since the only previous national survey, in 1986, when approximately 250 territories were found. The five regions of population that were apparent in 1986 all showed major increases, in particular in Breckland and the Suffolk Sandlings. Over 85% of territories occurred on heathland or within forest plantations. The ratio varied between regions: plantations were more commonly used in the north and east whereas more Woodlarks utilized heathland in the south. Woodlarks in Devon bred almost exclusively on farmland. More than three-quarters of the forest population was found in young plantations, particularly in stands of two and three year old trees. Most Woodlark territories were located on sandy soils, with nearly 70% specifically on acid sandy soils. Reasons for the observed increase and range expansion are discussed, as are the implications of habitat management practices.

Long term stability of White-necked Picathartes population in south-east Sierra Leone

Summary White-necked Picathartes Picathartes gymnocephalus is a globally ‘Vulnerable’ bird endemic to the highly threatened Upper Guinea forests in West Africa. In an environment under a high level of threat, the high breeding site fidelity (or breeding site persistence) of this species enables long term monitoring of colony site occupancy, colony size and other breeding parameters, which provide multiple indicators of population status. We surveyed known colony sites and searched for new sites in three recent breeding seasons in order to assess the current population status in the most important part of their range in Sierra Leone, the Gola Forest. We found 157 active nests at 40 colonies, equating to at least 314 adult birds. Less than half of the known colonies were protected by the Gola Forest Reserve. Colonies outside the reserve tended to be confined to larger rocks and subject to disturbance from human activities in close proximity, but did not have fewer active nests in them. Colonies outside the reserve were also more likely to be inactive in a given year whereas all colonies inside the reserve were active in every survey year. A predictive distribution model indicated that the survey region could have as many as 234 nests equating to at least 468 breeding birds. There was no evidence that mean colony size had declined since surveys undertaken in the 1980 sa nd1990s but it was not possible to compare colony abandonment rates inside and outside the reserve over that time period. Clutch and brood sizes were similar in each year, though brood size appeared slightly lower in the third survey year possibly because of a slightly later survey date. Mean clutch and brood sizes reported during the study period were similar to those found in the 1980 sa nd1990s. We conclude that the population of White-necked Picathartes in the Gola Forest area has been relatively stable over the last two decades, reflecting both the efficacy of protection afforded by the Gola Forest Reserve and presumably low pressure to farm new areas in the nearby community forest. However, regular monitoring of colonies both inside and outside the reserve is required to detect any systematic impact on the birds as pressure for land increases.