Bracken

Bracken

Bracken is a large fern found across much of Britain. It can reach 200cm in height and form dense impenetrable stands.

It is a natural part of many habitats, including heathlands, moorlands and woodlands, and can provide important shelter and nesting for a range of wildlife. It is also used by a number of scarce plants and animals.

What

In some circumstances bracken can be a very aggressive plant and can rapidly expand into, or colonise new areas of land, damaging other wildlife habitats, agricultural production and game management. Therefore it is sometimes necessary to proactively manage bracken areas to ensure other habitats or agriculturally important land are not damaged, or to maintain bracken cover at an acceptable level.

Bracken - Gethin Davies

Why

Areas of bracken can be beneficial to wildlife, particularly when they are found mixed with other habitats. Bracken provides breeding sites for moorland birds including whinchats, ring ouzels and merlins, whereas nightjars, tree-pipits and warblers will use bracken for cover. Bracken is used by reptiles for shelter, dispersal and feeding and is particularly valuable for reptiles emerging from hibernation in spring. Eleven invertebrate species are found only on bracken, and many others use it as part of their diet, for example several species of fritillary butterflies use bracken areas with their caterpillars feeding on violets and then pupating under dead plant material. Often woodland plants such as bluebell, primrose and wood anemone grow under bracken providing valuable pollen and nectar for insects in the spring. To provide the greatest benefits for wildlife, bracken should be managed as part of the grassland, heathland or woodland habitat in which it grows.

Bracken can, however readily invade areas of grassland, heathland and moorland, reducing the area of these important wildlife habitats as well as damaging valuable grazing land. Bracken can also create problems for livestock farming as it can cause poisoning in grazing animals. Bracken litter can harbour the early life stages of sheep tick, which can transmit diseases such as louping ill in sheep and grouse, as well as Lyme disease to humans. Controlling bracken can therefore be used to increase the area of grazing and increase the health of grazing animals.

bluebells and bracken

How

Bracken can be managed to benefit wildlife and farming interests, however before embarking on a large-scale programme of control/management be aware of time and resource implications, and the wildlife interests on site. Bracken management and/or control needs to be undertaken extremely carefully.

Scattered bracken and stands of bracken interspersed with grassy or heathland patches can be managed effectively with grazing (sometimes in combination with mechanical methods). Spring/summer grazing can keep bracken in check as trampling will help to reduce the vigour of new growth. Extensive cattle or pony grazing, particularly during winter and early spring can also break up standing dead bracken and ground litter, creating open areas through the bracken which allows sunlight in, benefitting other plants and butterflies.

Large scale control of bracken, aimed at reducing the extent or dominance of bracken, or to prevent recolonisation is a major operation which requires on-going work over many years.

Bracken control is probably best avoided, or will require careful planning where:

  • Bracken cover is light or scattered and can be managed through grazing
  • Bracken occurs on steep slopes which may be subject to erosion
  • A woodland ground flora (e.g. bluebells, wood anemone, violets) is present, which may also be important for fritillary butterflies and other insects
  • It may be better to manage for woodland (by planting or natural regeneration)
  • Only small patches occur, which could be used by reptiles or other wildlife
  • You are unable to carry out ongoing management

Bracken control should be considered where:

  • Bracken is, or has, the potential to invade important wildlife habitats or grazing land and  colonisation could be slowed, for example by sensitive management of the ‘leading edge’ of bracken stands (note reptiles often use these areas)
  • Bracken may be preventing the regeneration of trees or scrub
  • Ground vegetation remaining under the bracken has potential to recover

Bracken Management and Control Measures

A number of different methods, either in isolation or combination, are available for bracken control. None of these techniques will eradicate bracken completely however they can be used to manage the extent/density of bracken stands. Before carrying out new management look over the land, ideally in July, to identify how it is used by nesting birds, reptiles, butterflies or other wildlife.

Cutting

Cutting can help to reduce the dominance of bracken. It is best carried out around mid June when bracken is 50-75cm high and again six weeks later. If only one cut a year is possible do this in late July. Cutting will need to be repeated for at least three years and possibly into the longer-term. Where ground nesting birds are present delay cutting until late July. If sites are used by reptiles it is best to use chemical control.

Crushing or bruising

Using agricultural rollers or specialist bracken ‘bruisers’ is less effective than cutting but has the advantage that equipment is less likely to be damaged while working on difficult terrain. It is best carried out twice a year for at least three years. It should not be used when ground nesting birds or reptiles are present (see links below)

Chemical control

This is an effective control mechanism, and can be less damaging to some wildlife such as reptiles which can be harmed by crushing or bruising. Contact a trained agronomist for advice on the chemicals currently available to use.

Grazing

Grazing, particularly with cattle or ponies can be used as part of bracken management. Temporary mob stocking in May and June can crush/bruise bracken, however care is needed not to damage bird nests, reptiles and/or vegetation under the bracken canopy. Ensure enough other forage is available on the grazing unit to prevent stock eating the bracken. Livestock can also be used over the winter to break up dense bracken litter and to damage buds or fronds developing below the surface. Winter feeding sites can be used to help concentrate livestock onto bracken areas.

Controlled burning of bracken litter can be helpful by providing access for machinery or grazing animals, and can also encourage germination of grasses and other plants. As a general method of control burning is not recommended. It is sensible not to burn heathland with scattered bracken stands as this may encourage future growth of bracken. Always follow the ‘Heather and Grass Burning Code’ or the ‘Muirburn Code’.

Bracken - aberedw 2 Gethin Davies

More information

Bracken management - Amphibian and Reptile Conservation

Bracken control - Scottish Natural Heritage

Bracken for butterflies - Butterfly Conservation

Edgar, P., Foster, J. and Baker, J. (2010) Reptile Habitat Management Handbook. Amphibian and Reptile Conservation, Bournemouth

In practice

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