MANAGING ROAD VERGES FOR SAFETY AND BIODIVERSITY
When we talk about Biodiversity we are talking about the variety of all life on earth.
Within Carmarthenshire there are more than 6000 kilometres of road verges. The Highway
Authorities have a statutory duty to maintain the highway in a safe condition for all road
users, but it is also important to recognise the importance of the road verges for biodiversity
(or nature conservation). This importance comes about in four ways:
• Verges sometimes contain plants that have become less common in farmed areas.
Where pastures have been improved for agriculture and are now cut for silage, the
verges may contain a wider variety of plants than the adjacent land.
• They provide shelter and a source of food for wildlife. The later the verges are cut the
greater this benefit will be. Flowering plants and tall grasses are an important source of
food and provide shelter for a wide range of insects, seed feeding birds and small
mammals.
• Verges provide wildlife corridors and contribute to the overall network of habitats across
the county, linking hedgerows, woodlands and watercourses.
• Verges often occur in conjunction with other habitats important for biodiversity such as
ancient and/or species-rich hedgerows and ditches. The greater the variety of habitats
available, the greater the benefits for biodiversity in that area.
The way in which verges are cut will affect their value for biodiversity (or nature
conservation), and positive steps can be taken to enhance this:
1. Start date of cutting and cutting plan.
Many verges, especially those in the rural areas, support a wide range of plants. Some of
these plants, such as primroses, flower and set seed early in the year, before the end of
May. Others flower later in the year and it is these species which are adversely affected by
early cutting, for example devil’s bit scabious - a small button-like blue flower found on the
higher land, meadow sweet, often found on slightly damp ground and valerian, a tall late
flowering plant.
Recommendations
•
Start cutting as late as possible in the season, and cut the roads at lower altitude
first, finishing with the roads verges on the higher land.
•
Where possible do not cut flowering plants, and plants which have yet to flower.
2. Consider the nature of the vegetation you are cutting.
Verges adjacent to woodlands often contain plants associated with that habitat - bluebells,
wood anemone, or wild garlic, and on the higher land, heather and bilberry, or banks of
moss. These verges are often partially or completely shaded and the growth of the
vegetation is sparse.
Some verges and banks on the higher land will also contain bilberry and heather. Heather is
an important source of food for insects in August. This type of vegetation will rarely grow
beyond 45cm/18 inches in height, and that will take several years to achieve. It is unlikely to
interfere with visibility.
Recommendations
•
Where the verge is heavily shaded and vegetation growth is sparse avoid cutting,
or cut light and high.
•
Avoid cutting mossy banks, this will only damage the vegetation and may result in
erosion of the bank and slippage onto the road.
•
Consider carefully the need to cut the heather and bilberry vegetation on the higher
land e.g. Rhos Llangeller area. If you feel it needs to be cut, make this a high light
cut, as late in the season as possible. Ideally for nature conservation, such areas
should only be cut every 3 to 6 years.
3. Verges and associated habitats - hedgerows and ditches
In some areas the verge is very narrow, or may not exist at all. Here it is general practice to
cut the vegetation on the hedgebank to maintain visibility. Cutting of the shrubby growth
(the hazel, hawthorn etc.) in the hedge its self may be unavoidable. If absolutely necessary,
this should be done as lightly as possible particularly in May, June and early July as
bird will still be nesting in this part of the hedge, and should not be damaged or disturbed.
There should be no need to cut into the woody material of last year’s growth.
Some verges abut drainage ditches which, being wet, can support additional plants and
animals. Ideally some vegetation along side these ditches should be left un-cut, perhaps on
the far side of the ditch away from the road. Where there are plants in flower, or yet to
flower, aim to leave at least a proportion of these un-cut where this does not affect visibility,
for example where these are more than one swathe’s width from the road.
Recommendations
•
Wherever possible do not cut the shrubby growth in the hedge, the hazel, hawthorn
etc. Where there is no option, position the flail so as to avoid cutting into last
year’s woody growth.
•
Leave un-cut some vegetation on the banks of ditches, particularly where this
includes flowering plants or plants, which have not yet flowered.
Verges associated with more recently constructed roads may have a modified flora. These
can also be important for biodiversity, particularly where a combination of cut grass, long
grass, and shrubs an trees can be achieved.
Along some stretches of the highway, invasive exotic plants such as Japanese knotweed
now dominate, and to prevent further spread intensive management is often necessary in
these problem areas. These areas are outside the scope of this note, but please be aware of
them.
Species-rich verges can be an attractive feature of the landscape. Swathes of ox-eye daisies
on some of the trunk roads, and banks of bluebells, buttercups and orchids along country
lanes, all add to the beauty and quality of the countryside. Such qualities are important to the
image of Carmarthenshire. Well-managed verges can play an important role in attracting
tourism to the county, which is a major economic consideration, and they add to the quality
of life of those living in the county. The Council has received letters from the public
commenting on the beauty of the verges and the way they are managed. Your careful work
is appreciated!
The Carmarthenshire Local Biodiversity Action Plan (prepared by a partnership of 17
organisation working across the county) includes a Habitat Action Plan for verges
recognising their importance in the county, and setting out how the verges should be
conserved. The County Council will be instrumental in implementing this plan, and to be
successful on the ground it will rely on the high level of skills provided by the flail operators,
and your willingness to implement the above recommendations.
Enhancing the biodiversity of the county's road verges is a task included for performance
monitoring by the Council's Environmental Management System, which is accredited to ISO
14001 standard.
In order to develop training for future years we would welcome feedback on the
above. Please discuss these recommendations with your supervisors and line
managers, and ask them to pass on your comments. Thank you for your co-operation.
MANAGING ROAD VERGES FOR SAFETY AND BIODIVERSITY
GUIDANCE FOR CONTRACTORS – PLEASE READ AND TAKE NOTE
The way in which verges are cut will affect their value for
biodiversity (or nature conservation), and positive steps can be
taken to enhance this:
1. Start date of cutting and cutting plan.
•
Start cutting as late as possible in the season, and cut the roads
at lower altitude first, finishing with the roads verges on the
higher land.
•
Outside settlements cut vegetation within one swathe width of
the carriageway edge along straight stretches. NB Neatness is
not a priority – the verge that is left is a valuable habitat for
wildlife and a valuable seed source.
•
Where possible do not cut flowering plants, and plants which
have yet to flower.
2. Consider the nature of the vegetation you are cutting.
•
Where the verge is heavily shaded and vegetation growth is
sparse avoid cutting, or cut light and high.
•
Avoid cutting mossy banks, this will only damage the vegetation
and may result in erosion of the bank and slippage onto the road.
•
Consider carefully the need to cut the heather and bilberry
vegetation on the higher land, e.g. Rhos Llangeller area. If you
feel it needs to be cut, make this a high light cut, as late in the
season as possible. Ideally for nature conservation, such areas
should only be cut every 3 to 6 years.
3. Verges and associated habitats - hedgerows and ditches
•
Wherever possible do not cut the shrubby growth in the hedge,
the hazel, hawthorn etc. Where there is no option, position the
flail so as to avoid cutting into last year’s woody growth.
•
Leave un-cut some vegetation on the banks of ditches,
particularly where this includes flowering plants or plants which
have not yet flowered.
