Hedgerows provide vital resources for mammals, birds, and insect species. As well as being an important habitat in their own right, they act as wildlife corridors allowing dispersal between isolated habitats.
Biodiversity 2020 and Hedgerows
Biodiversity 2020: A strategy for England’s wildlife and ecosystem services is the Government’s strategy for people and wildlife in England. It was published in 2011 and replaces the previous England biodiversity strategy, the UK-BAP, when biodiversity strategy was devolved down to the four governments.
Biodiversity 2020 sets out to “halt overall biodiversity loss, support healthy well functioning ecosystems and establish coherent ecological networks, with more and better places for nature for the benefit of wildlife and people.”
The Biodiversity 2010 Strategy’s outcomes for hedgerows are;
Outcome 1A: 90% of hedgerows in favourable or favourable recovering condition by 2020
Outcome 1B: 6,000 km* (1280ha) of new hedgerow by 2020
The definition is that which originated from the UK-BAP “any hedgerow consisting predominantly (at least 80%) of at least one native woody species of tree/shrub”. This is an expanded definition from the original HAP definition which was confined to “ancient and/or species rich” hedges only. This change was in recognition of the fact that hedgerows are important features of the countryside and fulfil an important connectivity function.
Furthermore wildlife is not restricted to species-rich hedgerows or ancient hedgerows, and as hedgerow trees are not restricted exclusively to these types either, their wildlife is more generally distributed.
The definition is limited to boundary lines of trees or shrubs and excludes banks or walls without woody shrubs on top of them. However, any bank, wall, ditch or tree within 3 m of the centre of the hedgerow is considered to be part of the hedgerow habitat, as is the herbaceous vegetation within 3 m of the centre of the woody hedgerow.
Hedgerow Features Important to Wildlife
Different features of a hedgerow will be important to different species. The more diverse in composition a hedgerow is the more species it is likely to support due to a diversity of flowering and fruiting times. In general, native hedge plants such as blackthorn Prunus spinosa, hawthorn Crataegus monogyny, hazel Corylus avellena, dogwood Cornus sanguinea and field maple _Acer campestris will support many more species than non-native plants such as garden privet, Ligustrum ovalifolium, leylandii and sycamore Acer psedoplatanus. Older hedgerows often contain a large amount of dead wood and plant litter within the structure of the hedge and can provide a valuable habitat for many invertebrates (which in turn will attract predators such as bats, shrews and birds) and cover for small mammals. Hedge bases are an important feature and provide a buffer zone to protect root systems and which can be an important habitat in its own right.
Management practices are crucial to the maintenance of a healthy hedge beneficial to wildlife: hedge laying, where the layed stems die off as the new shoots grow provides a source of dead wood. Coppicing, where stems are cut just above the ground, can provide a new lease of life to seriously damaged hedgerows. The timing of management is important to get the best from a hedge and avoid disturbance to animals breeding or over-wintering. The cutting cycle will determine the availability of fruits and flowers in a hedge; typically a cycle of two to three years is most beneficial for wildlife.
Hazel dormice Muscardinus avellenarius are one of our rarest small mammals. There are still native populations as far north as the Lake District, Cumbria and Northumberland but they have been lost in other northern and central counties. Their current stronghold is in southern England and Wales.
Hedgerows play an important role for dormice. They emerge in spring and in the following months they generally spend all their time above ground in the trees and scrub. In April they feed on blackthorn and hawthorn flowers to replace body fat used in hibernation. In early summer they feed on ash Fraxinus excelsior keys, honeysuckle Lonicera periclymenum flowers and insects such as aphids Aphis sp. Later in the year they rely on blackberries and hazelnuts to provide the food resource to build fat reserves for the coming winter. The diversity of plants as food resources is therefore vital in supporting dormice. They are used as dispersal corridors and are an important link between small copses that are too small to support a viable dormouse population on their own. Crucially they also support breeding populations independent of other habitats. The huge loss of hedges has led to isolated populations and local extinctions. Even small gaps in a hedgerow will provide an obstacle to dormouse dispersal. Research carried out by Royal Holloway, University of London, has shown that hedgerows support as high numbers of dormice as woodlands do, so their removal will have significantly reduced dormouse populations nationally.
For more information on hedges and dormice see the Dormice and Hedges in Devon leaflet from Devon County Council, and the Hedgerows for dormice leaflet by the PTES (people’s trust for endangered species)
Linear landscape features such as hedgerows are important for bats. Hedgerows, woodland edge and ditches can all form commuting routes between roosting sites and feeding areas. These features can aid navigation and provide shelter from wind during flight. Hedgerow trees may also provide roosting opportunities for bats throughout the year. A network of well connected hedgerows and other linear features within a landscape allows many species of bat to extend their foraging and roosting capacity. Hedgerows also provide a habitat for insect courtship, breeding and feeding, hence providing foraging areas for bats. Some species of bats (such as the greater and lesser horseshoe Rhinolophus ferrumequinum, R. hipposideros, brown long-eared Plecotus auritus and Natterer’s bat Myotis natt ereri) take insects directly from foliage (known as ‘gleaning’) and tend to stay close to or within vegetation cover. Hedgerows also comprise an important foraging habitat for barbastelle bats Barbastella barbastellus. Hedgerow removal can lead to the loss of important connections within the landscape for commuting bats and also a reduction in insect diversity and hence foraging opportunities. Management of hedgerows for bats should aim to produce tall (ideally a minimum of 3m), wide and continuous hedges, comprising native species.
Bank voles Clethrionomys glariolus are habitat specialists that prefer woodland and hedgerows with dense shrubby cover. Mature and diverse hedgerows provide food and nesting habitat for harvest mice Mus minutus, with the main nest-supporting shrub species in field margins being bramble Rubus fruticosus and thorns Crataegus monogyna and Prunus spinosa. Hedgehogs Erinaceous europaeus probably rely on hedgerows to nest in especially in areas where arable farming is dominant. Habitat edges including hedgerows and also used for foraging for beetles and other invertebrates
Larger mammals such as stoats Mustela erminea and bedgers Meles meles will also use hedges for food and shelter.
Species-rich hedgerows can provide an important habitat for invertebrates. They supply food, shelter and breeding sites for pollinators such as bees and for pest predators such as scorpion flies Panorpa communis. Bumble bees Bombus spp. are known to use hedgerows to guide their foraging activity. Stag beetles Lucanus cervus can sometimes be found among decaying stumps at the base of a hedge. All invertebrate species are affected by insecticide, herbicide and fertiliser spraying regimes which will impact on invertebrate predators. Maintaining a diversity of perennial plants in the hedge bottom for host and nectar plants is beneficial to invertebrate diversity.
More than 20 of the butterfly species found in lowland Britain breed in hedgerows, including the brown hairstreak butterfly Thecla betulae, a priority BAP species, which lays its eggs on blackthorn. The Holly blue Celastrina argiolus butterfly caterpillars will only be found in hedges containing holly or ivy whilst the brimstone Gonepteryx rhamni prefers buckthorn Rhamnus cathartica or alder buckthorn Frangula alnus. The Purple Emperor Apatura iris and Pearl-bordered fritillary Boloria euprhrosyne are among species that use hedgerows for nectar, basking or as transport corridors from other ‘core’ habitats. Hedges are also used by some species such as the Peacock as territorial sites; males establish perching sites on hedges and rise up to inspect other butterflies as they fly past. The Barberry carpet moth Pareulype berberata , also a BAP Priority species, lives in hedgerows.
Features that affected the butterfly density of hedgerows include shelter from wind, insolation, nectar plant diversity, plant species richness, margin area and uncropped land. For optimal butterfly activity, hedges should create a network where shade and shelter are available as long as possible as the weather conditions change. The presence of farm tracks adjacent to hedgerows negatively effected butterfly density.
Cutting hedgerows immediately after harvest removes flowers important to over wintering butterflies and can destroy over-wintering juveniles stages. Trimming hedges on rotation every second or third year is thought to reduce these problems. Rotational cutting of hedge-bases will also prevent loss of nectar plants and leaf hibernacula for groups such as the skippers.
Many species of birds are associated with hedgerows. Woodland birds such as blue tit Parus major, great tit Parus caerulus, wren Troglodytes troglodytes, blackbird Turdus merula, robin Erithacus rubecula and chaffinch Fringilla coelebs are more common in taller, wider hedges. A taller hedge provides more habitat and is therefore more likely to provide space for a larger number of breeding territories. Birds that favour scrubby or open woodland, such as dunnock Prunella modularise, yellow hammer _Emberiza citrinella and whitethroat Sylvia communis, also use hedgerows. The hedge plants also provide songposts and perches for territorial and breeding birds. The nests, as they age, may then support populations of invertebrates. The hedge base is important for ground-nesting species like the grey partridge Perdix perdix.
Hedgerows which connect with ponds help great crested newts Triturus cristatus move through the countryside (Langton et al 2001).
BAP species linked to hedgerows
UK Biodiversity Action Plan: Priority species linked to hedgerows
This report and accompanying spreadsheet
identifies 130 priority BAP species (following the 2007 revised list) known to be significantly associated with hedgerows, including their trees, banks, basal flora and immediate margins. While few of these species are dependent on hedgerows alone, the loss of hedgerows, or a decline in their quality, would be likely to have an adverse affect on their populations.
Hedgerows are of particular importance to the conservation of threatened lichens (10 species), invertebrates (72), reptiles and amphibians (5), birds (20) and mammals (11).
The majority (69%) of associated species are widespread within the UK, including most of the birds and mammals. While still often common, these widespread species are recognised as priorities for conservation action because their populations have declined rapidly in recent decades. Many of them are dependent on the existence of a variety of different habitats in close proximity, so require conservation action to be taken at the landscape scale.
All 130 species occur in England, 104 in Wales, 83 in Scotland and 59 in Northern Ireland. South-West England and South East England are the regions with most priority species.
All major structural components of the hedge are important. Excluding those species for which insufficient is known about their ecological requirements (that is 51 widespread moths), over half (57%) use hedgerow trees, 42% the shrubby component, 41% the base and 34% the margin. Many species use more than one structural component. The high value of hedgerow trees is of particular note given that numbers of such trees are currently falling rapidly.
It is recommended that Hedgelink, together with biodiversity groups operating at the country level, should ensure that the needs of the 90 widespread species are taken into account in the delivery of the hedgerow Habitat Action Plan and, where necessary, of other priority HAPs. Regional and local BAP partnerships should take a lead on those species for which their areas are of particular importance, including rarities that require site-specific action.
Hedgelink has selected 12 flagships species against to which to measure the impact of its policies, action and advice. Collectively they represent the requirements of nearly all 130 species. They are: purple ramping fumitory, orange-fruited elm-lichen, large (moss) carder bee, goat moth, brown hairstreak, common lizard, bullfinch, tree sparrow, yellowhammer, soprano pipistrelle, hedgehog and dormouse.
Hedgerow Management and Wildlife Review
A review of research on the effects of hedgerow management and adjacent land on biodiversity. This report starts with a review of hedge management, including its history, current status and costs. It then continues by examining what is known about the effects of hedge management on wildlife, including the effects of associated land use management. This main section of the report has been divided up according to major taxonomic groupings with a section devoted to each.
Read the report: Hedgerow Management and Wildlife (.PDF 1.12MB).
Bat Conservation Trust
The Bat Conservation Trust
Butterflies and Farmland
Hedgerows for Hairstreaks
Dover, J. and Sparks, T. (2000) A Review of the ecology of Butterflies in British Hedgerows, Journal of Environmental Management 60, 51-53.
Hedgerow management for species leaflets
A report and a series of leaflets have recently been published following completion of a research project funded by Defra. The project, Understanding the combined biodiveristy benefits of the component features of hedges, aimed to increase our understanding of the role hedges play in supporting biodiversity. The report presents information on the importance of managing all hedge components optimally for biodiversity and the inter-relationship of the five structural components of hedges (trees, shrubs, hedge base, field margin and ditches). The focus is on priority species listed in Section 41/42 of the Natural Environment and Rural Communities Act (2006) and equivalent legislation in other UK countries (i.e. former BAP species), together with species listed as Biodiversity 2020 Farmland.
A suite of nine advice sheets relating to particular animals or assemblages of animals were written based on analysis. At a farm scale, there was very little conflict between the requirements of the chosen species. It was therefore possible to produce a further advice sheet, giving general advice on optimal management for hedge biodiversity.
- 2013 Annex C Review of Environmental Stewardship hedge provisions (PDF)
- 2013 Annex D Bibliography for Hedgerow FINAL (PDF)
- 2013 Hedgerow contract final report V6c (PDF)
- Bats & Hedges Leaflet (PDF)
- Bumblebees & Hedges Leaflet (PDF)
- Complete Good Hedge Management Guide Leaflet (PDF)
- Dead Wood Insects & Hedges Leaflet (PDF)
- Ditch Invertebrates & Hedges Leaflet (PDF)
- Dormice & Hedges Leaflet (PDF)
- Grass Snakes & Hedges Leaflet (PDF)
- Hairstreak Butterflies & Hedges Leaflet (PDF)
- Hedgehog & Hedges Leaflet (PDF)
- Complete Hedge Management Guide for Farmland Birds Leaflet (PDF)