Highways Agency

Overview of Effects

Disturbances from the existing motorway already impact on existing habitats and species. In order to minimise effects on habitats and species the Scheme includes a variety of mitigating measures. These include low noise surfacing, environmental barriers, sustainable drainage and new planting, together with habitat reinstatement and enhancement. These mitigation measures are in line with the Highways Agency Biodiversity Action Plan.

Designated ecological sites remain largely unaffected by the Scheme. There is little or no change compared with the current situation. However, new lighting has a negative impact on certain species of bats in some locations.

A programme of mitigation and a Construction Environmental Management Plan controls construction effects and ensures improvements are implemented.

The creation of new species-rich grassland, together with the reinstatement of plantation and hedgerows, improves the connection between habitats.

Species-specific measures, including bird boxes, bat boxes and water vole ponds, further improves many areas for species.

Badgers

Badgers and their setts are protected under the Protection of Badgers Act, 1992. The Badgers Act was implemented mainly to protect badgers from baiting and deliberate harm or injury, but also contain restrictions that apply more widely. Badgers are protected under the Badgers Act of 1990 against killing or injury. Detailed surveys revealed badger to be present along the Scheme. The majority of setts were inactive, although seven were identified as active main setts and a further seven were identified as active subsidiary and outlier setts. Various other signs of badger were recorded such as latrines, badger hair and paths.

Any work likely to involve disturbance to active badger setts requires licensing. The Scheme possesses suitable areas for supporting badgers throughout the route and the location of setts, runs and foraging areas has been established. Suitable mitigation will be implemented before construction commences.

Bats

All native species of bat in the UK are protected by the Wildlife and Countryside Act, 1981 (Schedule 5) and as amended by the Countryside and Rights of Way (CROW) Act, 2000. They also receive protection through the Conservation (Natural Habitats, & c.) Regulations 1994 (Schedule 2), which implements the EC Habitats Directive 92/43/EEC in the UK. A total of seven species of bats were recorded during survey work, with a total of 23 foraging areas of Parish/Neighbourhood importance; 9 foraging areas of District/Borough importance; 4 forgaging areas of County/Metropolitan importance; 2 active roosts and 5 carriageway crossing points identified. Species recorded were common pipistrelle, soprano pipistrelle, noctule, serotine, daubentons, leislers and brown-long eared bat.

Direct impacts from the proposals may involve disturbance or destruction of roost areas. Foraging habitat, consisting of scrub, woodland edge, marshes and rough unimproved grassland may be removed and artificial lighting will also affect bat foraging behaviour. Significant bat numbers are present and these will experience some effects to foraging areas from increased lighting. These include one foraging area of County/Metropolitan Importance and three foraging areas of District/Borough Importance. New treatment ponds and hedgerows provide additional foraging habitat.

Breeding birds

All bird species are protected under the Wildlife and Countryside Act, 1981 as amended by the Countryside and Rights of Way (CROW) Act (2000). Those species’ listed under Schedule 1 of the Wildlife and Countryside Act (1981) are protected by special measures at all times. Numerous breeding birds were identified including Schedule 1 species and Red and Amber List species (Red List Conservation Concern of County Importance). These included barn owl (Tyto alba), hobby (Falco subbuteo) and kingfisher (Alcedo atthis). Although no key areas of value for breeding birds were located within the Scheme Boundary a number of important areas are adjacent such as Nockhill Wood.

Due to loss of breeding, foraging and shelter habitat breeding birds in the opening year will be affected. There will also be increased noise and lighting. By year 15, improved habitat quality, connectivity and the provision of features such as nest boxes will offset some of the negative effects. Reinstated planting will have matured, helping to minimise lighting effects upon breeding birds.

Deer

The Deer Act (1963 - amended by the Deer Act, 1991) prohibits the taking or killing of deer listed on the schedules within the act during the close season for that species. Although there were no specific surveys carried out for deer, incidental observations were made during other survey work. The majority of records relate to muntjac deer (Muntiacus reevesi). In addition, roe deer (Capreolus capreolus) prints were observed and incidental observations such as deer hair, droppings and footprints were recorded.

Environmental Barriers will present physical obstructions to deer movements and current indications are that deer are using underpasses and over bridges to cross the M25, thus reducing risks to the species. Loss of vegetation in the early years will remove cover and foraging habitat for deer but reinstated vegetation will have matured by year 15.

Dormouse

The dormouse is legally protected under Annex IV(a) of the EU Council Directive 92/43/EEC on the Conservation of Natural Habitats and of Wild Flora and Fauna (the Habitats Directive). This Council Directive was brought into law in the UK through the Conservation (Natural Habitats, and c.) Regulations, 1994. In addition, the dormouse is also specially protected under Schedule 5 of the Wildlife and Countryside Act (1981, plus subsequent amendments), reinforced by the Countryside and Rights of Way Act (2000). A total of twenty-eight suitable sites were targeted for surveys for dormice (Muscardinus avellanarius). Dormice were not recorded in any location.

Suitable habitat that could support dormouse has been identified by the Phase 1 survey. This usually consists of woodland edge habitats, dense and open scrub where it backs onto ancient woodland and hedgerows (often ancient and overgrown) with good connections to scrub and woodland habitats. Woodland management and planting of new hedgerows will lead to a beneficial effect upon dormouse habitats.

Fish

Fisheries were investigated only for the Millstream (River Gade) using electro-fishing. Only three species were captured, these being pike (Esox lucius), common gudgeon (Gobio gobio) and chub (Leucisus cephalus). Chub was the only species found in moderate numbers. It was concluded that the River Gade is of poor quality for fish, supporting few top predators such as pike.

Verge lighting will result in an increase in light spill along the river corridor, which may have a small affect on normal fish behaviour, however, there will be no significant change to the river quality which will result in a neutral effect upon fish.

Great Crested Newts

The great crested newt (Triturus cristatus) is protected by the Wildlife and Countryside Act, 1981 (as amended). This Act has been further amended by the Countryside and Rights of Way Act (2000). Newts also receive legal protection under the Conservation (Natural Habitats, and c.) Regulations (1994). A total of 137 ponds and 2 pond complexes (a collection of closely related waterbodies) were surveyed for great crested newt within 500 metres of the motorway. The species was recorded at a number of sites along the motorway.

New treatment ponds would present potential colonisation opportunities for Great Crested Newts, although they would be heavily disturbed during the opening year of the Scheme and would have periodic disturbance during maintenance operations. Habitat improvements, including provision of hibernacula, will improve  the habitat suitability for great crested newts.

Invertebrates

Some invertebrates are protected by the Wildlife and Countryside Act, 1981 in varying amounts including killing, injuring, disturbance and sale. Five locations were surveyed for terrestrial invertebrates. Further to these surveys, low numbers of common glow-worm (Lamptyris noctiluca) larvae were discovered, sheltering beneath reptile refugia. Incidental observations also include a number of dragonfly and damselfly (Odonata) species around balancing ponds and adjacent to watercourses.

Due to continuous lighting throughout the Scheme, there will be an adverse effect upon terrestrial invertebrates, such as moths and night-flying insects. Reinstated planting and planting of new habitats will increase habitat with a higher ecological value in some areas, and provision of increased calcareous grassland will lead to an improvement in invertebrate diversity.

Macro-invertebrates

Some macro-invertebrates are protected by the Wildlife and Countryside Act, 1981 in varying amounts including killing, injuring, disturbance and sale. The River Misbourne, River Chess and the Millstream (River Gade) were surveyed for aquatic macro invertebrates. No notable or protected aquatic macro-invertebrates were recorded for any of the watercourses.

Otters

The otter is protected by Wildlife and Countryside Act 1981 (Schedule 5), which has been amended further by the Countryside and Rights of Way Act (2000). It also receives legal protection under the Conservation (Natural Habitats, and c.) Regulations (1994). Evidence of otters was not found along the Alder Bourne, River Misbourne, River Chess, River Gade, Grand Union Canal and the Catharine Bourne. However, positive results were obtained for the River Colne and River Ver. It is concluded that otter will be present within the Scheme Boundary on these water courses as they are crossed by the motorway.

The provision of two artificial otter holts has been identified to provide females with a safe and secure refuge in which to raise young. This will encourage otters to become resident in the area.

Reptiles

The slow worm (Anguis fragilis), common lizard (Lacerta vivipara), grass snake (Natrix natrix) and adder (Vipera berus) are protected from killing, injuring and sale under Wildlife and Countryside Act, 1981 (Schedule 5). In general reptiles are uncommon along the length of the scheme, although they may be abundant in certain locations and are often associated with features such as railway lines and ancient woodland. Grass snake (Natrix natrix) and slow worm (Anguis fragilis) were recorded at several sites within the survey area.

Mitigation measures, such as the provision of hibernacula, will improve the habitat suitability for reptiles. Reinstatement of key foraging habitats, including negligible and calcareous grasslands, will provide a higher quality resource than currently present. New treatment ponds will also provide foraging habitat for grass snake as they will support amphibians.

Water vole

Water vole (Arvicola terrestris) habitat is protected under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended). This prohibits damage/destruction of place of shelter/protection S.9(4)(a) and disturbance while in a place of shelter S.9(4)(b) only. Water Vole were found in the Alder Bourne, River Misbourne, River Chess, River Ver and Catharine Bourne. Surveys were conducted 250 metres upstream and downstream of the Scheme Boundary. Water vole were also present on some wetland areas. It is concluded that water vole will be present within the Scheme Boundary on all of these water courses as they are crossed by the motorway.

Water vole will benefit from the provision of new ponds and habitat improvements.