Habitat Action Plans Summary

Habitat Action Plans - Ancient & Species Rich Hedgerows

Habitats_hedgerows.jpg (3771 bytes)

Description

The national habitat action plan covers boundaries made up of lines of trees and/or shrubs, although where they are found in combination with other features (banks, walls, ditches, verges etc.) these are also considered to be part of the hedge.

  • Ancient hedgerows (which tend to the most biologically diverse in terms of both plants and animals) are defined as those that were in existence before the Enclosures Acts (mainly passed between 1720 and 1840).
  • Species-rich hedgerows are defined as those containing an average of 5 or more native woody species per 30 m length (4 species in northern England, upland Wales and Scotland). Additionally, hedges containing fewer woody species, but a rich basal flora of herbaceous plants are included, although there are no hard and fast rules for identifying them.

Consequently, the majority of later hedges (which tend to be narrow, straight hawthorn hedges) are excluded from the national habitat action plan.

Benefits

  • Habitat provision - hedgerows are an important habitat for many plant and animal species, with over 600 plant species, 1500 insect species, 65 bird species and 20 mammalian species known to live or feed in them. Indeed hedges are the primary habitat for at least 47 species of conservation concern in the UK (including 13 that are globally threatened or rapidly declining), being of particular significance for butterflies, moths, birds, bats and dormice.
  • Wildlife corridors - hedgerows provide vital links between areas of suitable habitat for a number of species, including mammals, reptiles and amphibians.
  • Other - hedgerows also play vital agricultural, landscape, cultural and archaeological roles.

Legal Protection

  • Under the Environment Act 1995 powers are provided to regulate for the protection of important hedgerows. It is likely that notification will be required prior to the removal of hedgerows.
  • The EC Habitats Directive requires member states to encourage the management of hedges (particularly with a view to improving the ecological coherence of the Natura 2000 network) in their domestic policies and regulations. In the UK this is reflected in The Conservation (Natural Habitats etc) Regulations 1994, which recognise the importance of linear habitats, and PPG9 (Nature Conservation, 1994).

Current Status

In recent years hedgerow length estimates for the UK have suggested figures around 329,000 km for England (1993), 49,000 km for Wales (1993), 33,000 km for Scotland (1990) and 125,000 for Northern Ireland (between 1986 and 1991). Consequently, the national habitat action plan estimates that in 1995 the total was about 450,000 km (based on an estimated rate of loss of 5% per annum). Although there is little data on the proportion of this total made up of ancient and/or species rich hedgerows, estimates based on the percentages of certain hedge types in different areas suggest that there are around 190,000 km of this particular habitat in the UK. However, since 1945 there has been a dramatic decline in hedgerows (particularly in eastern England), such that between 1984 and 1990 around of the hedgerow length in England, Wales and Scotland was lost.

In the rest of Europe, the presence of ancient hedgerows is limited to parts of France, northern Italy, the Austrian Alps, Greece and the Republic of Ireland.

Threats And Issues

  • Removal - over the years a great number of hedges have been removed for the purpose of agricultural and other development, although this is becoming less of a problem.
  • Neglect - neglected hedges gradually turn into rows of trees and develop gaps, impacting on their ecological status. This has become more of a problem in recent years in response to increasing labour costs, and the loss of traditional skills.
  • Poor cutting - when cutting is incorrectly timed or excessively frequent, poor habitat conditions and gaps can be created, and species changes may occur.
  • Senescence - hedgerows may be lost as a result of old age and felling without replacement.
  • Herbicides, pesticides and fertilisers - the use of herbicides, pesticides and fertilisers right up to the hedge base results in nutrient enrichment and reduced species diversity.
  • Increased stocking rates - hedges may be damaged when large stock numbers have access to them. This not only damages the hedgerow environment directly, but may also result in the installation of fencing, which in turn makes hedge maintenance less of a priority, leading to neglect (see above).
  • Ranching - the practice of placing netting round several fields to create a larger grazing area exposes internal hedges to damage.

Objectives (As Pertinent To Agriculture)

The national habitat action plan specifies the following objectives:

  • To halt the net loss of species-rich hedgerows through neglect and removal by 2000, and all loss of hedgerows which are both ancient and species-rich by 2005 - in order to stop the decline as soon as possible, since they are largely irreplaceable.
  • To achieve the favourable management of 25% (approx. 47,500 km) of ancient and species-rich hedgerows by 2000, and 50% (approx. 95,000 km) by 2005 - on the basis that most hedges require some long term management since if they are left to their own devices for more than 10 years there is a serious danger of them either becoming so open that they cease to be hedges, or declining beyond the point from which recovery is possible.
  • To maintain the overall number of hedgerow trees in each county/district at at least current levels by ensuring a balanced age structure - surveys suggest that the number of hedgerow trees is declining, and that the younger age classes have declined most (i.e. the population is getting older).

Conservation Advice

1) General

  • Prioritisation - management priority should be given to old hedges that include a diversity of shrub species, mature trees, and that are located adjacent to or linking other valuable habitat areas.

2) Hedgerow planting

  • Siting - new hedges should be position in such a way as to support those hedges and other habitats already present on the farm; for instance by linking areas of woodland or filling gaps in old hedge lines. Hedgerows should not be planted in areas where they are not a traditional part of the landscape as this can have a negative impact on wildlife.
  • Species choice - in order to obtain maximum environmental benefit, at least five native species of shrub should be included in the hedge planting, particularly those that have been shown to grow well in the locality. Care should be taken to avoid species that harbour crop pests such as barberry and buckthorn (carry rusts), and spindle (black bean aphids).
  • Techniques - a denser bushy structure is encouraged by planting shrubs in a staggered double row, and trimming the top of the hedge each year until the desired height is reached.
  • Trees - where possible tree species such as hawthorn, rowan, crab apple and field maple should be included in the planting regime.
  • Banks and ditches - if these can be included valuable additional habitats will be created.
  • Fencing - new hedges may need to be protected from grazing pressures, or in some cases from rabbit damage.
  • Weeds - young plants may require protection from competitive weed species; consequently, mulches or carefully selected herbicides may need to be used until the hedge becomes established.

3) Hedgerow management

  • Time of trimming - if cutting is too frequent, the production of flowers and fruit may be reduced or eliminated, having a marked impact on food availability. This can be particularly damaging to bees that rely on the supply of pollen in hedges early in the season when other on farm food sources may be scarce. Therefore, it is recommended (Andrews and Rebane, 1994) that if hedges are cut in the autumn they can be cut every three years, and if the cut is in early spring they can be cut every two years (hedges should never be cut between the beginning of April and the end of August). However, more regular cutting may be needed when hedges contain trees and shrubs that may become unmanageable if left for the full three years, and it may also be necessary to cut the top more often than the sides if crop shading is a problem. If possible however, some stretches should be cut less frequently than the rest (field corners etc). It is also advisable to rotate cutting so that not all the hedges in a given part of the farm are cut at once.
  • Hedge shape/size - hedge shape is not thought to be a major issue in determining conservation value, what is more important is size, since large hedges (at least 1.4 m high and 1.2 m wide) support a larger number of species (plant and animal) than small ones. Tall, bushy hedges also provide good wind shelter, providing a warmer, more humid climate on the leeward side (good for reptiles etc).
  • Laying - when hedges have been neglected for some considerable time, and become leggy, laying may be necessary to restore stock proofing. Most types of hedgerow shrub can be managed in this way, although a height of between 2.5 m and 5 m and stem diameter of between 5 cm and 10 cm at the base is usually required. Although this has a drastic impact on wildlife in the short term, the complicated internal structure of the resulting hedge, provides a wider range of nesting sites than would otherwise be the case.
  • Coppicing - coppicing can be used when there isn't sufficient growth for laying, or where the resulting barrier doesn't need to be stock proof. Species suited to coppicing include hawthorn, hazel, ash and oak; and although elm often doesn't coppice well, it will regrow from root suckers.
  • Old hedges - very old hedges containing a wide variety of shrub species may require a combination of the above management techniques.
  • Dead wood - where possible dead wood should be retained, since it provides food for invertebrates (some also burrow nests into it) and encourages the growth of fungi.
  • Fencing - in areas where grazing pressures are high, it may be beneficial to fence some stretches of the hedgerow in order to protect plant species.

4) Hedgerow trees

  • Planting - if possible self sown saplings should be incorporated into hedgerows, since these tend to be more successful (and cheaper) than planted trees. However, if planted trees must be used select species that are native to the locality and that have shown themselves to be suitable for the conditions. In all cases make sure that saplings are marked so as to avoid damage when the hedge is trimmed.
  • Pollarding - where previously pollarded trees remain it is advisable to reinstate management; however, care must be taken to avoid killing neglected trees by removing all the branches at the same time (remove half, and do the rest about three years later). New pollards can be established by cutting trees off at a height of 2-3 m when the trunk has reached a diameter of 10 cm at this height.
  • Old trees - if it is safe to do so, old trees and standing dead wood should be retained to provide a habitat for woodpeckers etc.
  • Felling - when old trees have to be felled, they should be replaced by the same species, particularly if it was an uncommon species.

5) Hedge surrounds

  • Hedge banks - although not strictly part of the hedge, such habitats are also covered by the national habitat action plan, and are valuable in their own right. Many are rich in wild plants, and they afford a greater level of protection to ground nesting birds than a ground level hedge base. In addition reptiles can often be found living in the structure of the bank, and use the sides for basking (particularly early in the spring and in the autumn). Consequently, hedge banks should be retained if possible.
  • Ditches - these too provide a good additional habitat, since some insects spend their larval stages in the moist banks, and move to the hedgerow vegetation to feed as adults. As well as being valuable themselves, these insects are an important food source for birds. Consequently, these too should be retained where possible.
  • Ploughing - avoid ploughing too close to hedge bases, as this destroys plants in the hedge base and damages the root structure of the hedge itself. It is advisable to leave a strip of perennial grasses at least 1 m wide each side of the hedge (see cereal field margins habitat).
  • Spray drift - the whole hedge should be protected against spray drift, since it kills non-target plants and invertebrates. This can be done by ensuring that adjacent fields are only sprayed when the wind speed is force 2 or less, and by turning off nozzles on the boom closest to the hedge when spraying immediately upwind. Ideally however, a permanently unsprayed field margin should be left (see cereal field margins habitat).

6) Support and assistance

  • Agri-environmental schemes - financial support for the renovation and planting of hedges is available through a number of agri-environmental schemes, including the Countryside Stewardship Scheme, the Environmentally Sensitive Areas (ESAs) Scheme and the Hedgerow Renovation Scheme (Wales).
    National Parks - local schemes exist in National Parks to support hedge management.
  • The Great Hedge Project - in 1993 Plantlife launched the Great Hedge Project, with the aim of creating a network of hedges across the country, and increasing public awareness of hedge issues.
  • Local groups - in 1994, the Devon Hedge Group was formed in order to promote the appreciation and management of hedges (a hedge pack is produced for Devon hedges). Similar groups have subsequently been formed in a number of other counties.

Contacts

At the national level, the habitat action plan for ancient and/or species rich hedgerows is being led by the Department for the Environment, Food and Rural Affairs (Defra), who have commissioned additional research into hedge management and establishment. Contact John Byng (Tel.: 020 723 85756).

In addition, the national plan suggests the following sources of information:

Other Biodiversity Action Plans Known To Cover This Habitat

Eastern England

 

Local Authority etc.

Bedfordshire and Luton
Borough of Dacorum
Cambridgeshire and Peterborough
Essex
Hertfordshire
Norfolk
Suffolk

East Midlands

Local Authority etc.

Leicester, Leicestershire and Rutland
Lincolnshire
Northamptonshire
Nottinghamshire

Other

National Forest

London

Local Authority etc.

Brent
Waltham Forest

North East England

Local Authority etc.

Durham
Tees Valley

North West England

Region

North West England

Local Authority etc.

Cheshire
Cumbria
Stockport

Scotland

Local Authority etc.

Clackmannanshire
Tayside

South East England

Local Authority etc.

East and West Sussex
Eastleigh
Hampshire
Oxfordshire
Surrey

South West England

Region

South West

Local Authority etc.

Bath and North East Somerset
Devon
Gloucestershire
South Gloucestershire
South Somerset
Teignbridge
Wiltshire

Other

Dartmoor National Park

Wales

Local Authority etc.

Anglesey
Bridgend
Caerphilly
Camarthenshire
Glamorgan
Greater Gwent
Merthyr Tydfil
Neath, Port Talbot
Pembrokeshire
Rhondda, Cynon, Taff
Torfaen

West Midlands

Local Authority etc.

Birmingham & the Black Country
Staffordshire
Warwickshire
Worcestershire

Other

National Forest

Yorkshire and Humberside

Region

Yorkshire and the Humber

Local Authority etc.

Bradford
East Riding of Yorkshire
Harrogate
Kirklees
Leeds
Rotherham
Ryedale
Scarborough
Selby
Sheffield

Related Action Plans

Habitats

Cereal field margins

Species

Dormouse
Greater horseshoe bat
Lesser horseshoe bat
Linnet
Pipistrelle bat
Song thrush
Spotted flycatcher
Tree sparrow

References And Further Information

Andrews, J. and Rebane, M. (1994). Farming & Wildlife: A Practical Management Handbook. The Royal Society for the Protection of Birds, Sandy, UK.

Carr, S. and Bell, M. (1991). Practical Conservation: Boundary Habitats. Hodder & Stoughton, London.

FWAG. (No Datea). Hedges and Field Boundaries. Farming and Wildlife Advisory Group, Kenilworth, UK.

FWAG. (No Dateb). Arable Farming. Farming and Wildlife Advisory Group, Kenilworth, UK.

FWAG. (No Datec). Handbook for Environmentally Responsible Farming. Farming and Wildlife Advisory Group, Kenilworth, UK.

Hill, D.A., Andrews, J., Sotherton, N.W. and Hawkins, J. (1995). Farmland. In: Managing Habitats for Conservation. (Sutherland,. W.J. and Hill, D.A.). Cambridge University Press, Cambridge, UK.

Sotherton, N. and Page, R. (1998). A Farmer's Guide to Hedgerow and Field Margin Management. Game Conservancy Limited, Fordingbridge, UK.

UK Steering Group. (1995). Biodiversity: The UK Steering Group Report, Volume 2: Action Plans. HMSO, London.

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