Trunk Road Biodiversity Action Plan: page 13

Trunk Road Biodiversity Action Plan: Review for Discussion

Stream Edges and Watercourses

Factors affecting these features are closely associated with bridges and drainage (see previous sections). New schemes should avoid physical changes to watercourses, or should retain the natural features created by the river as far as possible. New schemes also offer opportunities to restore damaged sections of watercourses and to re-engineer natural features such as meanders, which have greater biodiversity value.

Management activities along existing schemes near watercourses should be timed to minimise disturbance and damage and to avoid particularly sensitive times of year. Herbicide use should follow the guidance produced by Ministry of Agriculture, Fisheries and Food (see Links).

Mitigation measures should seek to address the whole system, not just individual species such as fish or otters. Watercourses and waterbodies may comprise only a part of the habitat requirements of a particular species. For example, amphibians use pools for part of the year to breed, but then disperse to other locations to feed and hibernate. The areas and routes involved in this process should be taken into account when working on and around water features.

Species/Groups	Sensitivities	Timing	Positive Actions
Fish	Free passage of fish along watercourses	All year	Follow Scottish Executive guidance on ensuring fish can migrate through culverts (e.g. under roads)
Badgers	Often have runs alongside streams	All year	Culverts/tunnels designed to allow them to carry on using habitual routes can reduce mortality rates
Otters	Otters may use watercourses and culverts to pass under carriageways See also Bridges	All year	Provide high water level access under bridges etc., to prevent otters crossing carriageways and suffering fatalities Use fencing to encourage use of otter passes Liaise with SNH/Vincent Wildlife Trust on appropriate local initiatives
Water Voles	Live and feed along banks favouring tall, lush vegetation. Their places of shelter are protected by legislation	All year	Where known to use ditches, seek to manage vegetation to provide suitable conditions. Avoid disturbance in breeding season, and damage to habitat within 1-2 metres of bankside

Links: MAFF guidelines for the use of herbicides on weeds in or near watercourses and lakes

An Inventory of Wildlife Mitigation Measures

Free passage of Fish

Wildlife Movements

This issue is linked to a number of road related features, including drainage and bridges.

Threats and influences

Animal deaths on roads can be a significant conservation issue as well as a safety hazard.
Roads can isolate populations of a species, preventing them from breeding with other groups. In the long term, this can reduce genetic diversity. Biodiversity objectives include the preservation of genetic variety, and this should be taken into account when maintaining free movement for vulnerable species.
The road as a barrier can affect a wide variety of invertebrates including ground beetles, wolf spiders, snails and butterflies. Certain species are able to cross roads safely, other species have poorer powers of dispersal. Roads may force species to move parallel to the road.
Roads may restrict the movement of reptiles and amphibians, although the instinct of frogs and toads to return to their breeding grounds is so strong they can suffer high mortality rates at road crossing points. Small mammals are also unlikely to cross larger roads, and so may be isolated from nearby food, shelter and nesting sites.

Opportunities

Amphibians, badgers, deer, otters, hedgehogs, red squirrels, birds of prey etc. would all benefit from measures to deter them from crossing at dangerous points. Such measures could include reflectors, fencing and verge planting.
Crossing assistance such as culverts, tunnels, underpasses and warning signs to drivers can be incorporated into road schemes. However, success depends on careful design and placement of features, an understanding of the target species and its behaviour and on-going maintenance to ensure long term use. For structures under roads, the larger the structure, the greater the variety of species that will be able to use it.
Provision of suitable linking habitat along roads can facilitate movement parallel to rather than across the carriageway. Species movement is helped by linking similar habitats. Partnership opportunities exist (e.g. with Forestry Commission and adjacent landowners) to facilitate linkages between habitats.
Identify local road kill 'hot spots' and set in place appropriate deterrents or alternative crossing assistance (refer to guidance).

Species/Groups	Sensitivities	Timing	Positive Actions
Badgers	Badgers cross roads at traditional crossing points Road kills will indicate where these crossing points are Features such as fences must be robust enough to guide strong and determined individuals	All year - badgers become particularly active in late February-March and again in autumn	Provide underpasses on new roads to allow safe passage under carriageways Use badger fencing to SNH specifications and landscaping to encourage use of underpasses Ensure installations are inspected and approved by an appropriate expert before client approval or opening of the feature for use Ensure existing features are maintained
Red Squirrels	Fragmentation of suitable habitat may restrict movement	All year	10 cm diameter rope bridges at suitable locations (see Forestry Commission work on B852 Dores to Foyers road at Loch Ness)
Otters	Otters will cross over carriageways where high river flow prevents access through culverts or under bridges Travel up and down stream may be restricted by road bridges and associated maintained embankments (see Bridges) Red reflectors currently in use in Scotland may not be effective on otters	All year	Provide underpasses with adequate high water access Use fencing to guide otters to underpasses Investigate use of white reflectors to test their effectiveness Liaise with SNH/Vincent Wildlife Trust Retain natural vegetation and bank-side trees as far as possible to provide cover. If tree removal for maintenance access is required, cut back to base and allow to regrow rather than grub out by the roots
Deer	Roe deer will often feed on new tree plantings and cross onto a road carriageway	All year	Use reflectors and fencing Warning signs to motorists
Small Mammals	Unlikely to cross larger busy roads. Tunnels unlikely to be used unless offering some intrinsic attraction Possible exposure to predation in open tunnels	All year	Roadside features to discourage crossing onto carriageways Experimental tunnel designs with different substrates to encourage use

Links: Cost Effective Landscape: Learning from Nature

An Inventory of Wildlife Mitigation Measures The Skye Agreement (Draft)

Urban Areas

While the urban habitat has a generally lower biodiversity, it is here that there can be the greatest opportunity to make an observable difference and to influence the largest number of people. Because green space is limited, relatively small improvements can make a significant difference. Roundabouts and verges are potential 'mini' wildlife habitats, and can improve the quality of the local environment. Here too there is scope to raise awareness through signs and other forms of interpretation.

The road network passes through many urban and semi-urban areas, and although the route objectives may be primarily concerned with man-made features, protecting biodiversity is still important and achievable. For example, many rural sustainable drainage practices can be adapted for the urban situation and native trees and shrubs are much underrated in their potential as decorative species as well as for their wildlife value.

Threats and influences

Over zealous management of verges, reducing species diversity.
Use of non-native species in planting schemes.
Wildlife road kills.
Perception that in the urban environment, a high level of management and maintenance input is required.

Opportunities

Provide suitable habitat to enable use of the transport corridor as a wildlife network, providing links and crossing points to facilitate movement. Corridors themselves are not useful unless they provide suitable conditions for movement along them.

Adopt less intensive maintenance practices, where appropriate, to encourage species diversity.
Plant native species, which can make a marked contribution to biodiversity in urban areas.
Non-native ornamental species, suited to a more formal urban setting, can also be highly beneficial to other species, providing food, shelter, nest sites etc

Species/Groups

Sensitivities

Timing

Positive Actions

Tree and Hedgerow species

Native and non-native species widely used

All year

Plant species with berries/nectar etc., of value to wildlife whether native or non-native

Ensure that native species are of local provenance, as per CEL:LfN Appendix 1

Grasses and flowers

Very fertile soils can reduce diversity by encouraging vigorous grass growth to the detriment of other species

Non-native species can also be valuable to insects, birds, small mammals etc.

All year

Avoid unnecessary fertiliser use when planting Retain poorer soils rather than importing expensive topsoil

Use species appropriate to the soil type, aspect and location

Select low maintenance mixes and insect attracting flowers whether native or non-native

Introduce mowing regimes designed to give managed appearance but incorporating uncut/infrequently cut areas

Links: Cost Effective Landscape: Learning from Nature

SEPA Habitat Enhancement Initiative publication ‘Watercourses in the Community - a guide to sustainable watercourse management in the urban environment

New Planting

Native species of trees, shrubs, grasses and flowering plants should always be used where they can perform the requirements of the design objectives. This applies to urban as well as rural situations (see also Urban Areas).

Native species selected to be appropriate to local conditions are likely to survive and grow on well, and to require less maintenance and aftercare once established.

Where native species are used they should be selected and sourced in accordance with Forestry Commission Guidelines and Appendix 1 of Cost Effective Landscape: Learning from Nature.

Woodland

Broad-leaved woodland holds a greater number of species of conservation concern (232) than any other broad habitat, including 78 globally threatened and rapidly declining species.

Native pine woodland (designated in the UK Biodiversity Action Plan as key habitat) is only found in Scotland. It holds 37 species of conservation concern listed by the UK Biodiversity Steering Group, including red squirrel, pine marten and wood ant.

Planted coniferous woodland (designated in the UK Biodiversity Action Plan as broad habitat), although created by man, includes red squirrel, black grouse, capercaillie, Scottish crossbill and goshawk.

All trees have some wildlife value, but in general older native trees support most species.

The characteristics of natural woodlands should always be used where the design objectives allow.

These include:

Using natural plant groupings, in terms of species mixes and spacing.
Creating diverse ground conditions.
Using existing native vegetation in the locality as potential sources of seed.
Leaving dead wood and stone in situ to create diversity of habitat.
Creating variable wet and dry ground conditions rather than a uniform and hence less diverse surface.

Threats and influences:

Clearance of areas for new roads or road improvement schemes.
Fragmentation of woodlands and other habitats.
Grazing and destruction of vulnerable areas by deer, sheep and other animals.
Inappropriate management or maintenance.
Invasion by non-native species or weeds, such as rhododendron, Japanese knotweed and Himalayan balsam.

Opportunities

Planting of appropriate local provenance native species to augment and link nearby woodlands.
Management to prevent encroachment of undesirable species.
Fencing to prevent grazing and encourage natural regeneration.
Sympathetic management to encourage diversity, e.g. leaving some dead wood in situ.
Create graded edges and buffer zones to increase diversity and link sites.
Introduce coppicing and pollarding of trees at suitable sites.
Trees planted in association with hedges and field margins are particularly valuable.

Species/Groups

Sensitivities

Timing

Positive Actions

Tree and Hedgerow species

Planting non-native species where native species would be preferable

All year

Ensure species appropriate to the locality and design objectives and of approved provenance are used. Following CEN:LfN guidelines - Appendix 1

Grasses and flowers

Very fertile soils can reduce diversity by encouraging vigorous grass growth to the detriment of other species

Inappropriate selection of species mixes can create sites with low wildlife interest and high maintenance requirements

All year

Avoid unnecessary fertiliser use when planting. Retain poorer soils rather than importing expensive topsoil

Use species appropriate to the soil type, aspect and location

Links: Scotland's Native Trees & Shrubs (forthcoming SE publication)

Cost Effective Landscape: Learning from Nature

An Inventory of Wildlife Mitigation Measures

Parking and Picnic Areas

This is where road users may gain some of their most significant and lasting impressions of Scotland's natural beauty and wildlife while on their journey. Parking and picnic areas are thus important for their potential contribution to local biodiversity and to encouraging a wider awareness and appreciation of wildlife and the environment by the public.

Threats and influences

Damage to habitats and species may arise through the behaviour of road users, for example unauthorised parking on sensitive habitats, litter and disturbance.

Opportunities

Measures such as fencing could be adopted to control users at particularly sensitive sites.
Information signs at service stations, picnic areas and lay-bys could be used to raise awareness and promote local biodiversity initiatives. Interpretation boards could be produced for particularly important locations in partnership with tourism, local authority or SNH initiatives.

Species/Groups

Sensitivities

Timing

Positive Actions

Various

Litter can damage and kill animals and plants

Small animals can become trapped in discarded bottles and cans

All year

Discourage indiscriminate disposal of litter

Provide appropriate information and signs to discourage littering

Locate lay-bys and stopping points away from very sensitive or protected sites

Noise or physical disturbance to vulnerable or sensitive species

Especially breeding season

Ensure parking and picnic locations are sited to avoid sensitive or protected sites and species

Use fencing to control access

Links: Cost Effective Landscape: Learning from Nature