Action: Pay farmers to cover the cost of conservation measures (as in agri-environment schemes)
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- Twenty-six studies from four European countries (including one UK systematic review and three European reviews) looked at the effects of agri-environment schemes on birds. Twenty-four studies (including one systematic review, six site comparisons and nine reviews) found increases in population size, density or more favourable population trends of some or all birds studied on sites with agri-environment schemes compared to non-scheme sites (some of these differences were seasonal). Eleven studies (including one systematic review and four reviews) found negative or no effects. One UK study found higher numbers of some birds where higher tier management was in place, another UK study found no difference between Entry Level or Higher Level Stewardship Scheme fields. One study from the Netherlands found that not all agri-environment scheme agreements were sited in ideal locations for black-tailed godwit.
- Eleven studies from five European countries (including three replicated paired site comparisons and two reviews) looked at the effects of agri-environment schemes on plants. Seven studies (including three replicated paired site comparisons and one European review) found agri-environment schemes maintained or had little or no effect on plants, plant diversity or species richness. Three studies found increases in plant species richness in areas with agri-environment schemes, two found decreases. A replicated site comparison study from Estonia found higher flower abundance on farms with agri-environment schemes in two out of four areas. A review found Environmentally Sensitive Areas in England had contributed to halting the loss of semi-natural grassland habitats but were less effective at enhancing or restoring grassland biodiversity.
- Ten studies from three European countries (including two replicated paired site comparisons and a review) looked at the effects of agri-environment schemes on invertebrates. Six studies (including two replicated site comparisons) showed agri-environment schemes maintained or had little or no effect on some invertebrates in terms of diversity, abundance, species richness or bee colony growth. Five studies found increases in abundance or species richness of some invertebrates. A UK study found agri-environment scheme prescriptions had a local but not a landscape-scale effect on bee numbers.
- Four studies (including two replicated site comparisons and a review) from the UK looked at the effects of agri-environment schemes on mammals. One study found positive effects, three studies found mixed effects in different regions or for different species.
- Three of the studies above found higher numbers of wildlife on land before agri-environment schemes were introduced. However two studies collecting baseline data found no difference in the overall number of birds or earthworms and soil microorganisms between areas with and without agri-environment schemes.
- A review found two out of three agri-environment schemes in Europe benefited wildlife.
Agri-environment schemes are government or inter-governmental schemes designed to compensate farmers financially for changing agricultural practice to be more favourable to biodiversity and landscape. In Europe, agri-environment schemes are an integral part of the European Common Agricultural Policy (CAP) and Member States devise their own agri-environment prescriptions to suit their agricultural economies and environmental contexts.
Since agri-environment schemes represent many different specific interventions relevant to conservation, and where a study’s results can be clearly assigned to a specific intervention, they appear in the appropriate section. This section, meanwhile, includes evidence about the success of agri-environment policies overall.
Evidence relating to the Swiss Ecological Compensation Areas with biodiversity monitoring on a landscape scale is placed under ‘Increase the proportion of natural habitat in the landscape’.
Supporting evidence from individual studies
A replicated study from 1992 to 1994 within the South Downs Environmentally Sensitive Area, Sussex, UK (Wakeham-Dawson 1995) found that Eurasian skylark Alauda arvensis numbers increased but brown hare Lepus europaeus numbers were stable over two years on the Environmentally Sensitive Area farms. There were significantly more breeding pairs of skylark in 1993 (5 males/km²) compared to 1992 (3 males/km²). The number of hares remained stable over the study period. Four arable, 10 mixed and three pastoral farms were studied. Hares were sampled by spotlight counting over an average of 26% of the area of each farm between November and March (1992-1993, 1993-1994). Skylarks were sampled by mapping breeding males during two counts along transects on 12-17 farms from April to June (1992 and 1993).
A 1997 review (Tilzey 1997) concluded that Environmentally Sensitive Areas had made a significant contribution to halting the loss of semi-natural grasslands in England, but were less effective in enhancing and restoring grassland biodiversity, a decade after introduction of the Environmentally Sensitive Areas scheme. The paper made a broad assessment of the effectiveness of the scheme in protecting England’s lowland semi-natural grasslands. Among Environmentally Sensitive Areas of greatest significance for their lowland grassland, six were of ‘outstanding’ significance (containing >40% of the English resource of a grassland type) and two were of ‘considerable’ significance (containing 10-40% of 1-2 grassland types or 5-10% of three or more grassland types). Entry of land supporting semi-natural grassland was generally high (e.g. covering 80% of chalk grassland in the South Downs Environmentally Sensitive Area). However, there was evidence in some Environmentally Sensitive Areas that grassland habitats were declining in quality due to management being insufficiently tailored to biodiversity interest e.g. permitting use of inorganic fertilizers.
A 1998 literature review (Ovenden et al. 1998) found that cirl bunting Emberiza cirlus in the UK responded positively to Countryside Stewardship Schemes, reaching population levels of 360-388 occupied territories in 1995-1997 (Evans 1997), compared with 118 or so in the mid-1980s (Evans 1992). Some of the interventions used include reducing grassland management intensity, sowing arable field margins, managing hedgerows for wildlife, growing spring barley, reducing herbicide use and maintaining overwinter stubbles.
Evans A.D. (1992) The numbers and distribution of cirl buntings Emberiza cirlus breeding in Britain in 1989. Bird Study, 39, 17-22.
Evans A.D. (1997) Cirl buntings in Britain. British Birds, 90, 267-282.
A 2000 literature review from the UK (Aebischer et al. 2000) found that the populations of four farmland birds (grey partridge Perdix perdix, cirl bunting Emberiza cirlus, corncrake Crex crex and Eurasian thick-knee (stone curlew) Burhinus oedicnemus) increased following agri-environment schemes targeted for them. The individual schemes are discussed in the relevant interventions.
A 2000 review of the effectiveness of agri-environment schemes in England (Reid & Grice 2000) reported that two bird species - Eurasian thick-knee (stone curlew) Burhinus oedicnemus and cirl bunting Emberiza cirlus had benefited from the introduction of agri-envrionment schemes. Numbers of cirl bunting increased from 118 pairs in 1989 to approximately 450 in 1998 following the introduction of measures including a ‘special project’ under the Countryside Stewardship Scheme. The review also stated that cirl bunting numbers showed a 82% increase in squares with Countryside Stewardship Scheme agreements between 1992 and 1998, but only a 2% increase on adjacent non-Countryside Stewardship Scheme squares. The number of Eurasian thick-knees increased from 150 pairs in 1991 to 254 by 2000 following the introduction of measures associated with agri-environment schemes including habitat management in the Brecks Environmentally Sensitive Area, and provision of nesting plots on set-aside as part of the Countryside Stewardship Scheme.
A paired site comparison study in 1992, 1998 and 1999 in south Devon, England (Peach et al. 2001) found that the number of cirl bunting Emberiza cirlus increased significantly more (up 72%, from 54 to 93 breeding territories) in areas participating in the Countryside Stewardship Scheme, than on adjacent land not participating in the scheme (down 20%, from 124 to 96 territories) between 1992 and 1999. Countryside Stewardship Scheme land that was near to known cirl bunting breeding territories saw greater increases in cirl bunting numbers than Countryside Stewardship Scheme areas further away - of the nine agreements further than 2 km from the nearest known breeding site in 1992, seven remained uncolonized in 1999, one lost its only pair and one gained a pair. Forty-one 2 x 2 km² squares containing both land within the Countryside Stewardship Scheme and non-Countryside Stewardship Scheme land were surveyed in 1992, 1998 and 1999. In each year each tetrad was surveyed at least twice, the first time during mid-April to late May, and the second time between early June and the end of August.
A study in 1997 in two Environmentally Sensitive Areas in eastern England (Ausden & Hirons 2002) found that higher tier options (i.e. those with more demanding prescriptions but higher financial compensation) held significantly higher densities of wading birds (northern lapwing Vanellus vanellus, common redshank Tringa totanus and common snipe Gallinago gallinago) than lower tiers (Tier 1: 0.02-0.04 pairs/ha; Tier 2: 0.07-0.22; Tier 3: 0.40). In addition, they held more waders for each unit of money spent on the Environmentally Sensitive Area (Tier 1: 18-46 pairs/£100,000; Tier 2: 29-114; Tier 3: 167). However, when examining 1988-1997 population trends in four Environmentally Sensitive Areas, the authors found all three species investigated declined significantly (lapwing: 1-13% decline each year, redshank: 2-19%, snipe: 7-30%).
A 2002 review of research on agri-environment schemes in England (Evans et al. 2002) summarized two reports (Wilson et al. 2000, ADAS 2001) evaluating the effects of the Pilot Arable Stewardship Scheme in two regions (East Anglia and the West Midlands) from 1998-2001. At the whole farm scale in winter, seed-eating songbirds, thrushes (Turdidae) and wagtails (Motacilla spp.) showed some benefit on agreement farms relative to control farms (numbers not given). In summer, numbers of breeding northern lapwing Vanellus vanellus, reed bunting Emberiza schoeniclus, greenfinch Carduelis chloris, house sparrow Passer domesticus, starling Sturnus vulgaris and yellow wagtail M. flava were higher on agreement farms. Agreement farms had some of the following options: overwinter stubbles (sometimes preceded by reduced herbicide, followed by fallow or a spring crop), undersown spring cereals (sometimes followed by a grass or grass/clover Trifolium spp. ley), arable crop margins with reduced spraying (conservation headlands), grass margins or beetle banks and sown wildlife seed mixtures (pollen and nectar or wild bird seed mix). Overwinter stubble (974 and 2200 ha in East Anglia and West Midlands respectively) and conservation headlands (605 and 1085 ha in East Anglia and West Midlands respectively) were the most widely implemented options. The effects of the pilot scheme on birds were monitored at the farm scale over three years, relative to control areas, or control farms.
Wilson S., Baylis M., Sherrott A. & Howe G. (2000) Arable Stewardship Project Officer Review. Farming and Rural Conservation Agency report.
ADAS (2001) Ecological evaluation of the Arable Stewardship Pilot Scheme, 1998-2000. ADAS.
A replicated site comparison study in southern England (Goulson et al. 2002) found no measurable difference in experimental buff-tailed bumblebee Bombus terrestris colonies in terms of colony growth, worker bee traffic, number or size of worker bees, queens and males produced or diversity of pollen collected between colonies on 10 farms with substantial conservation measures and those on 10 conventional arable farms. Conservation measures included conservation headlands, set-aside and minimal use of pesticides. Experimental bumblebee colonies were placed under hedges or shrubs on each farm, and every week nests were weighed and numbers of bees leaving and entering each colony counted for 10 minutes. Colonies were analysed after four weeks. The authors suggest the lack of difference is because the buff-tailed bumblebee has a foraging range that extends beyond individual farms, which may not be true for other bumblebee species.
A replicated site comparison study of 102 sites across East Anglia and the West Midlands, UK (Bradbury & Allen 2003) found that two years after the introduction of the Pilot Arable Stewardship Scheme (introduced in 1998) there was no difference in the number of farmland bird species observed in winter on Pilot Arable Stewardship Scheme farms and non-scheme farms. There were, however, significantly more seed-eating songbirds, wagtails and pipits (Motacillidae) on farms participating in the scheme than on farms not participating in the scheme. A further survey of 98 fields in summer found that although there were significantly more northern lapwing Vanellus vanellus, common starling Sturnus vulgaris, greenfinch Carduelis chloris and reed bunting Emberiza schoeniclus on Pilot Arable Stewardship Scheme fields, there were also fewer woodpigeon Columba palumbus, sedge warbler Acrocephalus schoenobaenus and rook Corvus frugilegus than on the non-Pilot Arable Stewardship Scheme farms. Fifty-four Pilot Arable Stewardship Scheme and 48 comparable non- Pilot Arable Stewardship Scheme farms were surveyed for farmland birds in both the winters of 1998-1999 and 1999-2000. Fifty Pilot Arable Stewardship Scheme and 48 non-Pilot Arable Stewardship Scheme farms were surveyed in the summer months of 1999 and 2000. The seed-eating songbirds identified included 13 species of finches (Fringillidae), buntings (Emberizidae) and sparrows (Passeridae), while the wagtails and pipits comprised three species. This study was part of the same monitoring project as (Browne & Aebischer 2003, Bradbury et al. 2004, Stevens & Bradbury 2006).
A replicated site comparison study of 71-76 farms in East Anglia and the West Midlands, UK (Browne & Aebischer 2003) found no consistent difference in the change in the number of brown hare Lepus europaeus and grey partridge Perdix perdix between 1998 and 2002 across either Arable Stewardship Pilot Scheme farmland or non-Arable Stewardship Pilot Scheme farmland. In East Anglia the density of brown hares increased on Arable Stewardship Pilot Scheme farms (from 16.2 to 20.0 hares/km²), but not on non-Arable Stewardship Pilot Scheme farmland (12.1 hares/km² in both 1998 and 2002). In the West Midlands hare densities fell slightly on Arable Stewardship Pilot Scheme plots (from 4.9 to 4.3 hares/km²) but not on non-Arable Stewardship Pilot Scheme plots (3.5 hares/km² in both survey years). In East Anglia grey partridge densities fell by 21% on Arable Stewardship Pilot Scheme farms (9.6 to 7.6 birds/km²) and 68% on non-Arable Stewardship Pilot Scheme farms (5.5 to 1.8 birds/km²), whereas in the West Midlands grey partridge densities fell by 78% on Arable Stewardship Pilot Scheme farms (3.0 to 0.8 birds/km²) and 40% on non-Arable Stewardship Pilot Scheme farms (1.4 to 0.8 birds/km²). Following the introduction of the Arable Stewardship Pilot Scheme in 1998, hare density data was collected after dark in the winters of 1998-1999 and 2002-2003 from 19 Arable Stewardship Pilot Scheme and 18 non-Arable Stewardship Pilot Scheme farms in East Anglia and 19 Arable Stewardship Pilot Scheme and 15 non-Arable Stewardship Pilot Scheme farms in the West Midlands. Surveys of grey partridge were made once each autumn in 1998 and 2002 on 76 farms: 20 Arable Stewardship Pilot Scheme and 19 non-Arable Stewardship Pilot Scheme farms in East Anglia and 20 Arable Stewardship Pilot Scheme and 17 non-Arable Stewardship Pilot Scheme farms in the West Midlands. This study was part of the same monitoring project as (Bradbury & Allen 2003, Bradbury et al. 2004, Stevens & Bradbury 2006).
A study from nine areas of the UK under Environmentally Sensitive Area schemes (Defra 2003) found that the impacts of Environmentally Sensitive Area designation on farmland birds were mixed. There was evidence for population increases or high numbers of some species of birds on Environmentally Sensitive Area-managed land for four Environmentally Sensitive Areas. Populations of some species were stable in six Environmentally Sensitive Areas, often in contrast to national trends, but four Environmentally Sensitive Areas saw falls in the populations of at least one target species. The authors also note that in five regions there were not adequate data for all target species.
A 2003 review of monitoring of agri-environment schemes in Europe (Feehan 2003) described long-term monitoring results (three years or more) for three agri-environment programmes in the UK, Ireland and the Netherlands. Some wildlife benefits were found for two of the three programmes: the Dutch Natuurbeheer (Kleijn et al. 2001 -study described under ‘Reduce management intensity on permanent grasslands’) and the UK Environmentally Sensitive Areas Scheme (Critchley et al. 2004, McEvoy et al. 2006), but not for the third scheme (the Irish Rural Environment Protection Scheme (Feehan et al. 2005)). The benefits were not always aligned with the scheme objectives.
Kleijn D., Berendse F., Smit R. & Gilissen N. (2001) Agri-environment schemes do not effectively protect biodiversity in Dutch agricultural landscapes. Nature, 413, 723-725.
A 2003 review of 62 studies from six European countries (Kleijn & Sutherland 2003) found that, overall, 54% of the species groups examined showed an increase in species richness or abundance under agri-environment schemes. Agri-environment schemes had no consistent effect on bird species. While there were individual successes, such as the 83% increase in cirl bunting Emberiza cirlus between 1992 and 1998 on land within the Countryside Stewardship Scheme compared with the 2% increase on adjacent land not in the scheme (Peach et al. 2001), only 13 out of 29 studies found agri-environment schemes increased bird species richness or abundance. Two studies reported negative effects and nine reported both positive and negative effects. Of the 19 studies which involved statistical tests, only four found positive effects, two reported negative effects and nine reported both positive and negative effects on species richness or abundance of birds. Half of the studies on plants that included statistical analyses (seven out of 14) found no effect, six studies found increased species richness/abundance and two found decreases. For insects and spiders (Araneae), 11 out of 17 studies that included statistical analyses found increases in species richness/abundance, none found decreases and three showed increases and decreases. Three out of the 62 studies included bees (Apidae). Two studies (Allen et al. 2001, Kleijn et al. 2001) found more bees (more species of bee in the case of Kleijn et al. 2001) on agri-environment fields compared to control fields under certain schemes. The third study (Kleijn et al. 1999) reported not to have found a difference in bee abundance or species richness between seven agri-environment fields and seven control fields.
Kleijn D., Boekhoff M., Ottburg F., Gleichman M. & Berendse F. (1999) De effectiviteit van agrarisch natuurbeheer. Landschap, 16, 227-235.
Allen D.S., Gundrey A.L. & Gardner S.M. (2001) Bumblebees: Technical appendix to ecological evaluation of Arable Stewardship Pilot Scheme 1998 2000. ADAS, Wolverhampton, UK.
Kleijn D., Berendse F., Smit R. & Gilissen N. (2001) Agri-environment schemes do not effectively protect biodiversity in Dutch agricultural landscapes. Nature, 413, 723-725.
A 2004 review of agri-environment scheme uptake and effectiveness in Europe (Berendse et al. 2004) found that in the UK, four rare bird species (grey partridge Perdix perdix, corncrake Crex crex, Eurasian thick-knee (stone curlew) Burhinus oedicnemus and cirl bunting Emberiza cirlus) benefited from agri-environment schemes (Aebischer et al. 2000). Although the authors note that densities of some species were higher on agri-environment scheme farms before they were designated. Similar methodological issues were found with studies in the Netherlands, where studies found that, at both field and larger scales, there were no population-level benefits of agri-environment scheme designation (Kleijn et al. 2001), although hatching and fledging rates of some species were higher on agri-environment scheme farms (eg. Musters et al. 2000, Schekkerman & Müskens 2000).
Musters J.M., Kruk M., de Graaf H.J. & ter Keurs W.J. (2000) Breeding birds as a farm product. Conservation Biology, 15, 363-369.
Schekkerman, H. & Müskens G. (2000). Produceren grutto's (Limosa limosa) in agrarisch grasland voldoende jongen voor een duurzame populatie? Do black-tailed godwits (Limosa limosa) produce sufficient numbers of offspring to maintain a sustainable population? Limosa, 73, 121-134.
Kleijn D., Berendse F., Smit R. & Gilissen N. (2001) Agri-environment schemes do not effectively protect biodiversity in Dutch agricultural landscapes. Nature, 413, 723-725.
A replicated site comparison study of 74 farms in East Anglia and the West Midlands, UK (Bradbury et al. 2004) found few differences in the density of farmland birds on farms participating in the Arable Stewardship Pilot Scheme and non-Arable Stewardship Pilot Scheme land, five years after the introduction of the scheme. In the West Midlands, although seed-eating songbirds, wagtails and pipits (Motacillidae), insectivores, and raptors were found at higher densities on Arable Stewardship Pilot Scheme land than non-Arable Stewardship Pilot Scheme land, these higher densities were already present when measured within one year of the introduction of the scheme. Moreover, in East Anglia there were no differences in the bird densities found on Arable Stewardship Pilot Scheme and non-Arable Stewardship Pilot Scheme fields. Surveys of grey partridge Perdix perdix populations on 76 farms in 1998 and 2002 found that adult densities decreased uniformly on both Arable Stewardship Pilot Scheme and non-Arable Stewardship Pilot Scheme farms over the five-year period. Bird surveys were carried out twice each winter, during the winters of 1998-1999 and 2002-2003 on 18 Arable Stewardship Pilot Scheme and 19 non-Arable Stewardship Pilot Scheme farms in East Anglia and 19 Arable Stewardship Pilot Scheme and 18 non-Arable Stewardship Pilot Scheme farms in the West Midlands. This study was part of the same monitoring project as (Bradbury & Allen 2003, Browne & Aebischer 2003, Stevens & Bradbury 2006).
A 2004 analysis of monitoring data (a replicated site comparison) in the UK (Critchley et al. 2004) concluded that agri-environment schemes maintain, but do not reliably improve, plant diversity in grasslands. In 22 of 38 datasets, no change was detected in the vegetation under agri-environment schemes. Nine showed some change towards the desired plant community, and seven showed further deterioration. Of 17 datasets that included non-agreement land for comparison, seven found agri-environment agreements were benefitting plant communities (deterioration or no change on non-agreement land contrasting with maintenance or restoration on agreement land). Two found more positive trends in plant communities outside agri-environment schemes than under them. In eight comparisons, there was no difference between agreement and non-agreement land. Thirty-eight sets of vegetation monitoring results were analysed. They included 188 specific agri-environment schemes aimed at maintaining, enhancing or restoring grasslands or grassland landscapes in the UK. These involved repeated monitoring over up to eight years, on between four and 400 locations/agri-environment scheme, using a range of sampling strategies.
A 2004 literature review of farmland bird declines in the UK (Newton 2004) found that 12 of 30 declining species have shown local population density increases after the implementation of agri-environment scheme options. Five out of ten seed-eating birds responded positively to agri-environment schemes, one (cirl bunting Emberiza cirlus) showing large increases. Three other songbirds, corncrake Crex crex, grey partridge Perdix perdix and two wading birds responded to agri-environment scheme options. A further seven species responded to local conservation measures and eleven species were not studied sufficiently were found not to respond to conservation measures or were recovering following national legislation (i.e. the prohibition of organochlorine pesticides).
A 2004 literature review (Vickery et al. 2004) describes how ten years of agri-environment schemes in the UK have failed to halt the decline of many formerly common farmland bird species. However, it also points out that specially-designed agri-environment scheme options have led to local-scale population increases of three rare and range-restricted species (corncrake Crex crex, Eurasian thick-knee (stone curlew) Burhinus oedicnemus and cirl bunting Emberiza cirlus) (Aebischer et al. 2000).
A replicated paired sites comparison study in 1999 and 2000 on 60 farms in three counties of Ireland (Feehan et al. 2005) found no consistent difference between Rural Environment Protection Scheme and non-Rural Environment Protection Scheme farms in plant or ground beetle (Carabidae) diversity or abundance. Non-Rural Environment Protection Scheme farms had the greatest range in species richness, and included farms with the lowest and highest numbers of plant species (23 and 50 plant species, respectively) and ground beetle species (12 and 30 ground beetle species). There were more plant species on grassland field margins on non-Rural Environment Protection Scheme farms (average 14.2 species/margin) than on Rural Environment Protection Scheme farms (12.5 species/margin). Sixty farms with Rural Environment Protection Scheme agreements at least four years old were paired with sixty similar farms without agreements. The farm pairs were in three Irish counties: Laois and Offaly (largely cattle farms with pasture) and Wexford (largely mixed arable farming). On each farm, two randomly selected hedges, the adjacent field margin and one watercourse margin were surveyed for plants and ground beetles. In each field margin and watercourse margin, all plant species were recorded in two 5 x 3 m quadrats, and percentage cover estimated in a 1 x 3 m quadrat. All plant species in a 30 m stretch of hedge were recorded. Ground beetles were sampled in four pitfall traps/field margin (eight traps/farm), set at 10 m intervals in early June and late August.
A replicated controlled trial from 1994-2004 in the five Environmentally Sensitive Areas in Northern Ireland (McAdam et al. 2005) (same study as (McEvoy et al. 2006)) found that overall, farms without Environmentally Sensitive Area agreements showed a decrease in invertebrate diversity, and a decrease in the number of plant species characteristic of infertile soils, while these decreases did not happen on Environmentally Sensitive Area farms. The number of plant species characteristic of infertile soils (stress-tolerant species) on hay meadows significantly increased from 1994-2004 on Environmentally Sensitive Area agreement farms, but decreased on farms without Environmentally Sensitive Area agreements (numbers n[ot given). Two ground beetle (Carabidae) species of conservation interest increased on farms with Environmentally Sensitive Area agreements between 1994 and 2004, each in one of the five Environmentally Sensitive Areas. The ground beetle Cymindis vaporariorum, characteristic of upland heaths and raised bogs, increased in the Glens and Rathlin Island Environmentally Sensitive Area; Carabus clatratus (a wet grassland/bog species) increased on participant farms in the West Fermanagh and Erne Lakelands Environmentally Sensitive Area. Plants, birds, spiders (Araneae) and ground beetles were monitored from 1994-2004, on farms with and without agreements, in the five Environmentally Sensitive Areas: Mourne and Slieve Croob (established 1988), Slieve Gullion (established 1994), Antrim Coast, Glens and Rathlin Island (established 1989), Sperrins (established 1994) and West Fermanagh and Erne Lakelands (established 1993). Monitoring was on permanent randomly placed quadrats, in seven habitat types: wet grassland, limestone grassland, unimproved grassland, hay meadows, heather moorland, woodland and field boundaries. Quadrats were partially surveyed every three years, and fully surveyed in 1994 and 2004.
A replicated, controlled trial in Estonia (Sepp et al. 2005) found no difference in numbers of earthworms (Lumbricidae) or soil microbial activity between arable soils with and without agri-environment schemes, in the first two years of a pilot agri-environment scheme. There were 32-224 earthworms/m2 of 1-5 species in the Jõgeva County area and 0-614 earthworms/m2 of 0-5 species in the Saare County area. The grey worm Aporrectodea caliginosa was dominant (81-89% of all earthworm individuals) in both areas. As the scheme had been in place for one or two years only, the authors considered these results to be baseline data, showing no initial differences in soils between agri-environment and control areas. The ‘Environmentally Friendly Production Scheme’ required restricted nitrogen fertilizer (100 kg/ha or less), limited field size, at least 15% of the cultivated area to be under legumes or grass and legumes, with cereals not grown for more than three years in a row, uncultivated field margins and maintenance of existing landscape elements, including semi-natural habitats. The pilot scheme began in 2001. For each pilot area, earthworms were monitored in one cereal field on each of ten farms with the Environmentally Friendly Production Scheme, and five farms without it, in an adjacent reference area. Earthworms were sampled by hand-sorting from five soil blocks 50 x 50 x 40 cm. Microbial activity was sampled by estimating the activity of dehydrogenase enzymes (the fluorescein diacetate method).
A replicated study in 2005 of 2,449, 1 km squares across arable and pastoral farmland in England at the start of the Entry Level Scheme (Chamberlain et al. 2006) found that there was no difference in the total number of bird species between 1 km2 of land participating in the scheme and areas not participating in the scheme. Eight bird species had a significantly higher occurrence on Entry Level Scheme squares, whilst seven species (mainly non-farmland bird species) had higher occurrences on non-Entry Level Scheme squares. Three species had higher abundance on Entry Level Scheme squares (all farmland specialists: linnet Carduelis cannabina, tree sparrow Passer montanus, stock dove Columba oenas) and 17 species were more abundant on non-Entry Level Scheme squares. There were 975 squares on land under the Entry Level Scheme land and a further 1,474 squares on conventionally managed farmland. Each square was surveyed twice along a 2 km transect route, recording all birds seen or heard. The Entry Level Stewardship scheme was introduced in 2005 and the data from this study was used to provide a baseline against which future surveys could monitor the effectiveness of the scheme.
A replicated before-and-after trial in Northern Ireland (McEvoy et al. 2006) (same study as (McAdam et al. 2005)) found that the number of plant species on land managed under the Environmentally Sensitive Area scheme over ten years was maintained but not enhanced on grasslands, and maintained in heather moorland in two of three areas for which results were reported. The number of higher plant species did not increase between 1993 and 2003 in the Environmentally Sensitive Area grassland sites, which were all in the West Fermanagh Environmentally Sensitive Area (33-41 species/transect). In heather moorland, average cover of heather increased in one of the five Environmentally Sensitive Areas (13 sites in West Fermanagh), but did not change at two others (43 sites in Sperrins Environmentally Sensitive Area, 6 sites in Antrim Coast Environmentally Sensitive Area). The number of plant species on heather moorland was maintained at these two Environmentally Sensitive Areas but declined between 1994 and 2004 in the Slieve Gullion Environmentally Sensitive Area (13 sites). Values are not given for heather cover or numbers of plant species on heather moorland. The study monitored plant diversity at 63 grassland sites and 93 heather moorland sites, first in 1993-1994 before the Environmentally Sensitive Area management began and again 10 years later. The sites were randomly selected from a database of farmers joining the Environmentally Sensitive Area scheme in 1993.
A replicated study in 1999 and 2003 on 84 farms in East Anglia and the West Midlands, UK (Stevens & Bradbury 2006) found that only three bird species (two in East Anglia, one in the West Midlands) showed a significant positive response to the introduction of agri-environment schemes (Arable Stewardship Pilot Scheme), whilst one showed a significant negative effect. Meadow pipit Anthus pratensis, carrion crow Corvus corone and reed bunting Emberiza schoeniclus either declined less or increased on farms under agri-environment schemes, compared to conventionally managed ‘control’ farms. Corn bunting Miliaria calandra declined significantly faster on agri-environment scheme farms. Overall, only six species showed any positive response (significant or not) in both regions. Ten species showed negative responses in both regions and 12 showed a positive response in one region and a negative response in the other. This study was part of the same monitoring project as (Bradbury & Allen 2003, Browne & Aebischer 2003, Bradbury et al. 2004).
A single farm, Rawcliffe Bridge, East Yorkshire, UK (Bryson et al. 2007) with a combination of conservation measures prescribed under the Entry Level Stewardship Scheme had higher densities of some bird species than the average for UK lowland farms. Meadow pipit Anthus pratensis, reed bunting Emberiza schoeniclus, Eurasian skylark Alauda arvensis, grey partridge Perdix perdix, corn bunting E. calandra and yellow wagtail Motacilla flava occurred in higher numbers in each monitoring year than the average lowland farm density (provided by the British Trust for Ornithology). For example, there were between 12 and 22 meadow pipit pairs/100 ha at Rawbridge, compared to a national average of less than three. Birds on the farm were monitored five times each year from 2003 to 2005, by walking the field boundaries. The number of breeding pairs/ha was estimated from clusters of sightings.
A replicated site comparison study in 2005 and 2006 on 31 farms in Seine-et-Marne, France (Chateil et al. 2007) found that agri-environment measures did not benefit plant diversity. The number of plant species was higher on farms with one or two agri-environment measures than those with none at all, but farms with between three and seven different agri-environment measures had generally fewer plant species than farms with very few measures. Plant diversity (Simpson’s diversity index) was unaffected by the number of agri-environment measures per farm. Twenty-six fields from 17 farms were sampled three times in 2005 (April, June, September). Sixty-four fields from 31 farms (including all those surveyed in 2005) were sampled twice in 2006 (April and July). Plants were recorded in ten permanent, regularly spaced, 1 m2 (0.5 x 2 m) quadrats along the permanent margins of each field.
A replicated site comparison study in Northern Ireland (Reid et al. 2007) found that areas with agreements under the Environmentally Sensitive Areas scheme did not have more Irish hares Lepus timidus hibernicus than areas outside the scheme (around 0.4 Irish hares/km on average). Rabbits Oryctolagus cuniculus and red foxes Vulpes vulpes were more abundant in Environmentally Sensitive Areas (around 2 rabbits and 0.5 foxes/km on average) than in non-Environmentally Sensitive Areas (around 1 rabbit and 0.2 foxes/km on average), both species are considered pests on farmland. One-hundred-and-fifty 1 km2 were randomly selected from within Northern Ireland’s five Environmentally Sensitive Areas. A sample of 50 non-Environmentally Sensitive Area squares were matched for land use, altitude, road type and distance from the Environmentally Sensitive Area boundary. Mammals were surveyed by spotlight on night drives in mid-winter 2005, on both sides of 1 km of road bisecting each survey square. Irish hares, rabbits and red foxes were counted.
A 2007 systematic review of 29 studies incorporating data for 15 farmland bird species in the UK (Roberts & Pullin 2007) found that there were significantly higher winter densities of farmland birds on fields under agri-environment schemes than on conventionally managed fields. Considering each scheme individually, there were greater winter densities of birds on fields within the Arable Stewardship Pilot Scheme, Countryside Stewardship Scheme, organically farmed fields, fields with set-aside, overwinter stubble, and wild bird cover than on conventionally farmed fields. Overall, eight species (53%) had significantly higher winter densities on agri-environment fields compared to conventional cropping (corn bunting Miliaria calandra, greenfinch Carduelis chloris, grey partridge Perdix perdix, northern lapwing Vanellus vanellus, linnet C. cannabina, rook Corvus frugilegus, Eurasian skylark Alauda arvensis and song thrush Turdus philomelos) and no species were found to have higher densities on conventional agricultural fields compared to those fields entered under agri-environment scheme agreements. Although both organic fields and set-aside fields in summer had significantly higher densities of farmland birds, there was no difference between the number of birds on conventionally farmed fields and Arable Stewardship Pilot Scheme fields in summer. Six species (35%; grey partridge, lapwing, woodpigeon Columba palumbus, skylark, rook and cirl bunting Emberiza cirlus) of the 17 for which summer data were available were found at significantly higher densities on agri-environment scheme fields compared with fields under conventional systems. The migratory yellow wagtail Motacilla flava was found at lower densities on scheme fields than on conventionally managed fields. In total 29 papers describing experiments conducted between 1985 and 2005 on a total of 12,653 fields (5,381 fields under agri-environment schemes and 7,272 fields farmed conventionally) were used for the meta-analysis. The meta-analysis included seven site comparison studies, five randomized controlled trials and 17 controlled trials.
A replicated site comparison study in four regions of Estonia (Viik et al. 2007) found more bumblebee Bombus spp. species and higher flower abundance on farms with agri-environment agreements in two of the four regions. In the central Estonian regions, with large fields and homogenous agriculture (Tartu and Jõgeva), organic and Environmentally Friendly Production Scheme farms had more bumblebee species than conventional farms (8-9 species/farm on organic or agri-environment farms, compared to around 5 species/conventional farm). There was no difference in numbers of bumblebee species or flower abundance between types of farm in the south and west Estonian regions (Võru and Saare). Bumblebees were monitored on 22 farms in each region - ten organic farms, six in the Environmentally Friendly Production Scheme and six conventional farms with no environmental agreement. Bumblebees were counted on 500 x 2 m transects, six times between June and August 2006, on days with temperature above 16 °C and wind speed less than 6 m/s. Flower abundance was assessed on the transects using a four point scale.
A site comparison study of 677 plots covering 38,705 ha across southern England (Wilson et al. 2007) found that for three wading bird species, population trends were more favourable (increasing or declining less rapidly) in areas under Environmentally Sensitive Area scheme options aimed at enhancing habitat than in the less expensive Environmentally Sensitive Area habitat maintenance options and in parts of the surrounding countryside not participating in the scheme. Nature reserves were shown to be most effective at maintaining wader populations. Between 1982 and 2002, common redshank Tringa totanus declined by 70% in the wider countryside but increased overall from 646 to 755 pairs (up 17%) on Environmentally Sensitive Area designated land, with the largest increase observed in nature reserves outside Environmentally Sensitive Areas (160%). Northern lapwing Vanellus vanellus showed a 48% decline in the wider countryside, and increased only in nature reserves outside Environmentally Sensitive Areas (by 55%) and reserves with Environmentally Sensitive Area enhancement (121%). Common snipe Gallinago gallinago breeding numbers decreased everywhere (commonly with declines of 90% or more), although declines were smaller in nature reserves outside Environmentally Sensitive Areas (−66%) and reserves in Environmentally Sensitive Area enhancement (−24%). The Environmentally Sensitive Area scheme was introduced in 1987 and offered payments for either maintaining or enhancing landscape quality and biodiversity. Breeding waders were surveyed in 1982 and 2002 at lowland wet grassland sites covering ten counties in England. In both years, three censuses were carried out at each site between mid-April and mid-June.
A before-and-after study, examining data from 1976 to 2003 from farms across southern Sweden (Wretenberg et al. 2007) found that four locally migrant farmland birds (northern lapwing Vanellus vanellus, Eurasian skylark Alauda arvensis, common starling Sturnus vulgaris and linnet Carduelis cannabina) showed less negative (or positive) population trends during 1987-1995, a period of agricultural extensification that included the introduction of agri-environment schemes, compared to in the preceding period of intensification (1976-1987). However, following the adoption of the Common Agricultural Policy (CAP) in 1995-2003, the species showed more negative population trends again, despite the widespread adoption of agri-environment scheme options. Three non-migrant species (house sparrow Passer domesticus, tree sparrow P. montanus and yellowhammer Emberiza citrinella) showed more diverse population trends and responses to agricultural changes were largely non-significant.
A replicated site comparison study over 20 years in the UK (Brereton et al. 2008) found that chalkhill blue butterflies Polyommatus coridon increased more on sites with agri-environment scheme agreements than sites without. Chalkhill blue numbers increased on average 3.16%/year at 66 sites with Countryside Stewardship Scheme or Environmentally Sensitive Area agreements, compared to no significant trend at non-scheme sites. Chalkhill blues were counted annually from 1981 to 2000, at 161 sites across its entire UK range. This was part of the UK Butterfly Monitoring Scheme, which takes weekly transect counts along a set route at each site and follows standardized weather conditions.
A replicated paired site comparison in Bavaria, Germany (Mayer et al. 2008) found that grasslands under the ‘Agricultural Landscape Programme’ (KULAP) did not have more plant species than control grasslands overall. There were 18-23 plant species/plot on sites with any KULAP agreement, compared to 18-22 plant species/paired control plot (215 site pairs). When considering only sites with site-related (rather than whole farm) agreements, there were more plant species under the KULAP scheme (around 22 species/site) than on paired control sites (<20 species/site; 90 site pairs). There were also more plant species/site on 58 Contract Nature Protection Scheme sites (25 species/plot) compared to paired control plots (about 17 species/plot). Nine-hundred-and-thirty-six pairs of 25 m2 grassland plots were selected from 4,400 plots in the Bavarian grassland survey. All plant species within the plot were recorded between April and October (year not given). Plot pairs were in the same natural landscape, 90% within 10 km of each other. In each pair there was one with and one without an agri-environment scheme agreement.
A study of the locations of Meadow Bird Agreements in the Netherlands (Melman et al. 2008) found that 43% of the 71,982 ha area of Meadow Bird Agreements in 2004 was located on sites where meadow bird populations are constrained for reasons other than those addressed by the agri-environment management. Twenty-two percent (15,798 ha) were outside the area of known black-tailed godwit Limosa limosa occurrence (more than five breeding pairs/100 ha in a 1998-2000 survey; 90-95% of other specialist meadow bird species breed in suitable black-tailed godwit habitat). Within the black-tailed godwit area, 11% (6,166 ha) of the Meadow Bird Agreement area was on heavily drained land, 4% (2,500 ha) was in landscapes not considered open enough for meadow birds, 10% (5,400 ha) was in areas of high traffic disturbance and an estimated 8% (2,834 of the 35,000 ha for which data were available) was on sites with high predation. The authors advocated targeting Meadow Bird Agreements to the 285,000 ha of land in the Netherlands with over five breeding pairs of black-tailed godwit/100 ha, but none of the other identified constraints.
A before-and-after replicated trial in the Yorkshire Dales National Park, UK (Pacha & Petit 2008) found that the average number of plant species in upland hay meadows fell from 19.5 species in 1980, before the introduction of agri-environment schemes, to 14.7 species in 2003, when the Countryside Stewardship Scheme and the Environmentally Sensitive Areas scheme had been employed for almost 20 years. One-hundred-and-nineteen fields surveyed in the 1980s and found to contain wood cranesbill Geranium sylvaticum were re-surveyed in 2003. In 47 of the fields, all plant species were recorded in ten 1 m2 quadrats at each site. Wood cranesbill was found in 76 of the 119 fields it had previously been found in, an extinction rate of 40%. The average nearest distance to another field containing the species increased from 121 m in 1980 to 1072 m in 2003. Fields located more than 300 m from another field containing the habitat were more likely to have lost the species.
A site comparison study of fifty-three 2 km² plots on 14 farms in southeast Scotland (Perkins et al. 2008) observed that between 2002 and 2004, the number of territorial male corn bunting Emberiza calandra fell by only 5% on plots that managed land according to the Farmland Bird Lifeline scheme, whereas numbers declined by 43% in non-Farmland Bird Lifeline plots in the same area. Between 2000 and 2002, before the 2002 introduction of the Farmland Bird Lifeline management practices, there was no observed change in the number of corn bunting on either group of plots, although plots destined to participate in the Farmland Bird Lifeline scheme did already have 33% higher densities of corn bunting than comparison plots. The Farmland Bird Lifeline scheme intended to reverse the declining numbers of corn bunting, a priority species in the UK Biodiversity Action Plan. Farmers were paid for a number of interventions, including delaying mowing date, providing grass margins on arable fields, farming spring cereals and turnips at low intensity, spring cropping, leaving unharvested crop, and supplementary feeding. Fourteen farms, nine in Aberdeenshire and five in Fife, were surveyed every breeding season (late April to August) from 2000 to 2004.
A site comparison study of ten 3 km² plots in Austria (Wrbka et al. 2008) showed that, compared to conventionally managed arable land, land farmed less intensively (under agri-environment schemes) had larger numbers of ground breeding birds (16.1 vs 13.2 individuals/10 ha), Red-listed birds (2.5 vs 1.8 individuals/10 ha), and Species of European Conservation Concern (13.9 vs 10.3 individuals/10 ha). Arable land managed for the conservation of particular species had 27.6 Species of European Conservation Concern individuals/10 ha and 28.6 ground breeding individuals/10 ha compared with the 11.1 individuals/10 ha and 13.7 individuals/10 ha, respectively, on conventionally managed farmland. Reed-breeding birds on grassland benefited from similar initiatives (11.3 vs 2.8 individuals/10 ha of farmland). Habitat conservation measures appeared to benefit ground breeders on arable farmland (16.6 vs 10 individuals/10 ha). Breeding birds were surveyed during three visits between April and June 2003.
A replicated, controlled trial involving 10 farms in east and central Scotland, (Lye et al. 2009) found that on farms managed under the Rural Stewardship Scheme, transects covering agri-environment options (unsprayed grassy field margins, species-rich grassland uncut from March-August and hedgerows only cut every three years) attracted significantly more nest-searching and foraging queen bumblebees Bombus spp. than conventionally managed transects. However, on conventionally managed transects (not agri-environment scheme options), there was no significant difference between farms with and without agri-environment schemes in numbers of nest-searching queens, and conventionally managed farms had more foraging queens. Five farms that signed up to the Scottish Rural Stewardship Scheme in 2004 were paired with five comparison farms less than 5 km away with similar land-use but no agri-environment participation. Bumblebees were recorded on six 100 x 6 m transects/farm, weekly in April-May 2009. Each farm had two arable field margin transects, two grassland transects and two hedgerow transects.
A 2009 literature review of agri-environment schemes in England (Natural England 2009) found that options and schemes varied in effectiveness for farmland wildlife. Breeding populations of some nationally rare birds increased after the implementation of options on arable farms (cirl bunting Emberiza cirlus pairs increased by 130%, Eurasian thick-knee (stone curlew) Burhinus oedicnemus pairs increased by 87%). A case study from a single farm found that grey partridge Perdix perdix numbers increased by more than 250%/year, corn bunting Miliaria calandra by over 100%/year and Eurasian skylark Alauda arvensis by 71%/year following the implementation of a number of different options. Productivity of some bird species was found to be higher on agri-environment scheme farms, which also provided key habitats. However, there was little evidence for any population-level beneficial effects of Entry Level Stewardship designations on widespread birds such as skylark or yellowhammer E. citrinella. Several of the studies reviewed argued that most agri-environment schemes were not well targeted to provide habitat for wading birds (Dutt 2004), although other studies argued that wader populations had declined less in regions designated as Environmentally Sensitive Areas than in the country overall (Wilson et al. 2005). Implementation of agri-environment schemes was also shown to benefit mammals, such as brown hare Lepus europaeus, with significantly higher densities on farms with agri-environment schemes than control farms in East Anglia. However in the West Midlands, hare densities were similar between agri-environment scheme farms and control farms (Browne & Aebischer 2003).
Dutt P. (2004). An assessment of habitat condition of coastal and floodplain grazing marsh within agri-environment schemes. RSPB report to Defra, London.
Wilson A. M., Vickery J. A., Brown A., Langston R. H. W., Smallshire D., Wotton S. & Vanhinsbergh D. (2005) Changes in the numbers of breeding waders on lowland wet grasslands in England and Wales between 1982 and 2002. Bird Study 52, 55-69.
A replicated paired sites study on farms across Scotland under two agri-environment scheme prescriptions (Countryside Premium Scheme and Rural Stewardship Scheme) in spring-summer 2004-2008 (Parish et al. 2009) concluded that the schemes had little impact on farmland biodiversity. Whilst 280 agri-environment scheme farms had more birds of more species than 193 non-scheme paired farms (averages of 140 birds of 23 species on 105 Countryside Premium Scheme farms vs 108 of 20 on paired non-scheme farms; 108 birds of 19 species on 88 Rural Stewardship Scheme farms vs 86 of 17 on paired farms), trends did not vary between scheme and non-scheme farms, and scheme farms had higher species richness and abundances before entering schemes. Differences held for all species and for nationally threatened species. Time since entry into the Countryside Premium Scheme did not appear to affect the number of species or bird abundance, except, for a small decline in the abundance of tits Parus spp. In addition, no evidence was found for differing effects of schemes in different regions of Scotland, or on different farm types. There were generally more plant species and individuals and higher plant diversity on farms managed under the Countryside Premium Scheme than non-Countryside Premium Scheme farms (e.g. for one agri-environment scheme option there were 20 plant species on scheme farms vs 15 on non-scheme farms), but very limited evidence of significant differences in plant species richness, abundance or diversity between Rural Stewardship Scheme and non-Rural Stewardship Scheme farms - where there was a difference there were more plant species or higher diversity on the Rural Stewardship Scheme farms. There were no significant differences in butterfly (Lepidoptera) species richness or abundance between Countryside Premium Scheme and non-Countryside Premium Scheme farms, and no significant differences in the number of ground-active beetles (Coleoptera) between Countryside Premium Scheme or Rural Stewardship Scheme and conventionally managed farms. Plants, ground-active beetles and butterflies were already generally more abundant or more species rich on Rural Stewardship Scheme sites when they joined the scheme (during first survey year 2004-2005).
A before-and-after study on one farm in Oxfordshire, UK (Taylor & Morecroft 2009) found that following a change to management under the Environmentally Sensitive Areas scheme (also leading to organic certification), the numbers of large moths (Lepidoptera), some species of butterfly and ground beetle (Carabidae), and the number of plant species, including butterfly larval food plant species, increased. The butterfly species that increased after Environmentally Sensitive Area management included the brown argus Aricia agestis, the common blue Polyommatus icarus and the small copper Lycaena phlaeas. Overall butterfly and ground beetle numbers, and numbers of pipistrelle bats Pipistrellus pipistrellus and P. pygmaeus and Daubenton’s bats Myotis daubentonii also increased over the entire time period, but the increase did not happen after management change. Butterflies, plants, ground beetles and bats were regularly monitored on the farm from 1994 to 2006 inclusive. In 2002, the farm entered the Environmentally Sensitive Areas agri-environment scheme. The proportion of grassland increased, fertilizers, herbicides and pesticides were no longer used, and the total number of livestock dropped from 180 cows and 1000 sheep to 120 cows and 850 sheep. The land was certified organic in 2005.
A controlled study in 2002-2009 on mixed farmland in Hertfordshire, UK (Aebischer & Ewald 2010) found that the estimated population density of grey partridge Perdix perdix was significantly higher on land under agri-environment schemes, than on conventional arable crops. This study also examined the densities found on set-aside (which were similar to those on land under other agri-environment schemes), wild bird cover (which were considerably higher than on other land uses) and the impact of predator control and supplementary food provision. Grey partridges were surveyed in March and September using dawn and dusk counts starting in 2001. Land cover within the project area was mapped and categorized as: conventional arable land, arable in agri-environment schemes, non-arable, or set-aside (which was further divided into non-rotational, wild bird cover, other rotational).
A replicated site comparison of 2,046, 1 km squares of agricultural land across England in April-June 2005 and 2008 (Davey et al. 2010a) (same study as (Davey et al. 2010b)) found that farmland bird population responses to Entry Level Stewardship schemes varied regionally. The authors suggest that detailed, regional prescriptions may be more effective in stimulating bird population growth than uniform agri-environment schemes. Field margin management took place in 36% of squares and did not have clear impacts on ‘field margin’ species: two species responded positively in at least one region, three species showed positive and negative responses in different regions, one only negative responses and the other six showed no significant responses.
A large site comparison study in 2005 and 2008 of 2,046, 1 km² plots of lowland farmland in England (Davey et al. 2010b) (same study as (Davey et al. 2010a)) found that the Countryside Stewardship Scheme and Entry Level Stewardship schemes had no consistent effect on farmland bird numbers three years after their introduction in 2005. Between 2005 and 2008, eight Farmland Bird Index species showed significant declines on arable plots, nine species declined significantly on pastoral plots and six species declined on mixed farmland squares (farmland plots covered with less than 50% arable and less than 50% pastoral farming). Only goldfinch Carduelis carduelis, jackdaw Corvus monedula, and woodpigeon Columba palumbus showed population increases between 2005 and 2008. Although certain farmland bird species did show landscape-specific effects, there were no consistent relationships between farmland bird numbers and whether or not the plots contained Entry Level Stewardship and Countryside Stewardship Scheme land, or the financial cost of the agri-environment interventions, or the length of hedgerows or ditches under an agri-environment scheme, or the availability of wild bird seed mix and overwinter stubbles (i.e. some species showed increases in response to a particular intervention on a particular landscape-type but not on other landscape-types, and these changes were not consistent between species). The 2,046 1 km² lowland plots were surveyed in both 2005 and 2008 and classified as arable, pastoral or mixed farmland. Eighty-four percent of plots included some area managed according to the Entry Level Stewardship or Countryside Stewardship Scheme. In both survey years, two surveys were conducted along a 2 km pre-selected transect route through each 1 km² square.
A replicated site comparison study from 2004 to 2008 on 1,031 agricultural sites across England (Ewald et al. 2010) found that in three out of four year-on-year comparisons, grey partridge Perdix perdix density changes and overwinter survival were higher on sites under agri-environment schemes, than on sites not under schemes (partridge density changes were more positive on agri-environment scheme sites than non-agri-environment scheme sites in all comparisons except 2007-2008, overwinter survival was higher for all years except 2006-2007). However, these differences were only significant in 2005-2006 for density changes (6% increase on agri-environment scheme sites vs 11% decrease on non-agri-environment scheme sites) and 2006-2007 for overwinter survival. There were no consistent differences between agri-environment scheme and non-agri-environment scheme sites with respect to brood size. When schemes were investigated individually, only Countryside Stewardship Scheme sites and Environmentally Sensitive Areas sites had significantly more positive density trends than non-scheme sites, and only in 2005-2006 (6% increase on Countryside Stewardship Scheme and Environmentally Sensitive Area sites vs 12% decline on non-agri-environment scheme sites), although other years and schemes showed a similar pattern. Overwinter survival, brood size and the ratio of chicks to adults did not show consistent effects across different schemes. A higher proportion of sites under the Partridge Count Scheme implementing the options most beneficial to partridges was higher than the proportion of non-Partridge Count Scheme sites. Various methods of succession management (rough grazing, scrub creation, scrub control, grassland creation) were negatively associated with the ratio of young to old partridges in 2008.
A small site comparison study between November 2007 and February 2008 on 75 fields in East Anglia and the West Midlands, UK (Field et al. 2010) found no difference between the numbers of seed-eating birds in fields managed under Higher Level Stewardship of the Environmental Stewardship scheme and numbers in fields managed under Entry Level Stewardship. Entry Level Stewardship fields had overwinter stubbles, no post-harvest herbicide application and no cultivation until mid-February and were sown overwinter with wild bird seed mix. Higher Level Stewardship fields were sown with enhanced wild bird seed mix and the stubbles had the same basic Entry Level Stewardship requirements plus reduced herbicide use and cereal crop management before overwintered stubbles.
A before-and-after trial of the Entry Level Stewardship scheme (an option within the Environmental Stewardship scheme) on a 1,000 ha lowland arable farm in central England (Hinsley et al. 2010) observed that the number of seed-eating birds was higher on both Entry Level Stewardship and conventionally farmed fields in the winter of 2006-2007 than during the previous winter (2005-2006) when the Entry Level Stewardship scheme was first introduced. This increase was greater on Entry Level Stewardship plots setting aside 5% of farmland to provide winter bird food (with an average of 70 birds/km of transect in 2007 vs five birds/km of transect in 2006) than on conventionally farmed fields (25 birds/km of transect in 2007 vs ten birds/km of transect in 2006). Although there were also more summer breeding territories of seed-eating species, chaffinch Fringilla coelebs, dunnock Prunella modularis, and robin Erithacus rubecula on the farm as a whole in 2007 than in the previous breeding season (2006), there was no difference in this increase between Entry Level Stewardship and conventional fields. Land managed according to the minimal environmental requirements was compared both with fields where 5% of land was removed from production and replaced with patches of winter bird food and field margins (6-8 m). Winter birds were surveyed from transects on three visits (November, December, and January) in both the winters of 2005-2006 and 2006-2007 - i.e. before and after bird food patch establishment. Breeding territories were surveyed during four visits (April, May, June, and July) in 2006 and 2007.
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