Dr Phil Eades Consultant Ecologist WETLAND ECOLOGY · BOTANICAL SURVEY· PROTECTED SPECIES

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24 June 2011

Greatmoor Access Road Botanical Survey Introduction A botanical survey was undertaken of the disused railway line at Greatmoor that forms the proposed access route for the Energy from Waste plant at Calvert. The survey was carried out by Dr Phil Eades on 13-14 June 2011, during fine, warm weather. The multiple aims of the survey were: • •

• • • •

to make gps-referenced target notes of relevant features along the route; to gather detailed plant species lists for the railway line, with a particular focus on species that are known to be larval food-plants for a number of important butterfly and moth species; to map zones of open mosaic habitat (a priority BAP habitat) and adjacent scrub; to produce a series of cross-sections at representative points along the route; to take digital photographs at representative points along the route; to note the presence or absence of tall, screening hedgerows or scrub.

Survey Outputs The main outputs from this survey are: 1. an Excel spreadsheet detailing all target notes, species-lists, photographs and cross-section locations, and the relative abundance of larval food-plants; 2. digital photographs of the site; 3. hand-drawn cross-sections at indicative locations; 4. habitat plans drawn onto the Ramboll’s access road layout plans; 5. this document, which summarises the main findings of the survey; 6. present a series of discussion points to engage with the road design engineers to avoid or reduce the predicted impacts of road construction presented in the October 2010 planning application (Ramboll Drawing Reference 7493/C/...Planning Issue 10/2010). Site Description The disused railway line is flanked for the whole of its length by tall hedgerows or scrub belts of varying width, and height ranging from about 4-10 metres, with occasional young mature trees. Sleepers (and rails) are present for most of the route, from Target note 10 southwards. The

railway line itself runs roughly north to south, and bends to the north-west and south-west at the northern and southern ends respectively. It runs variously through shallow cuttings between 0.3 – 2 metres in depth, and embankments ranging from 0.5 – c. 3 metres in elevation. A strip of herbaceous vegetation is sandwiched between the scrub belts, and this varies in width from about 2 metres to about 8 metres. Generally speaking, the wider sections support lowgrowing herb-rich vegetation on thin, dry (or non-existent) soils over railway ballast. These areas often include butterfly & moth larval food-plants, and while the vegetation is very sparse in the centre of the strip, it tends to thicken towards the edges. Narrower strips that are heavily shaded by encroaching scrub tend to be dominated by more robust species such as nettles, thistles and brambles. A number of plant species that support rare or scarce butterfly and moth species are present along the railway line, including mature blackthorn and a number of herbaceous plant species of open mosaic habitats. Very little young blackthorn was observed on site. Butterfly & Moth Larval Food-plants The frequency of the larval food-plants of a number of butterfly and moth species along the access route was noted during the survey (see Table 1). Table 1. Frequency of lepidopteran larval food-plants along the Greatmoor access route. Plant species Abundance Habitat Larval food-plant of: Agrimonia eupatoria Rare Grassland Grizzled skipper Brachypodium Rare Grassland Wall brown sylvaticum Cornus sanguinea Occasional Hedgerow Green hairstreak Holly blue Festuca arundinacea Frequent Grassland Small heath Festuca rubra Frequent Grassland Small heath Fragaria vesca Frequent Open vegetation Grizzled skipper Hedera helix Rare Open vegetation Holly blue Ligustrum vulgare Occasional Hedgerow Lotus corniculatus Occasional Grassland Dingy skipper Green hairstreak Malus sylvestris Rare Hedgerow Figure of eight Potentilla reptans Abundant Open vegetation Grizzled skipper Prunus spinosa (mature) Abundant Hedgerow Black hairstreak Figure of eight Prunus spinosa (young) Rare Low scrub Brown hairstreak Rosa canina Frequent Low scrub & hedgerow Rhamnus catharticus Occasional Hedgerow Green hairstreak Rubus fruticosus Abundant Low scrub & grassland Green hairstreak Grizzled skipper Holly blue Rumex acetosa Occasional Open vegetation & Small copper grassland The Forester Salix caprea Occasional Hedgerow Purple emperor Ulmus procera Rare Hedgerow White letter hairstreak Viola hirta Frequent Open vegetation & Dark green fritillary grassland Viola riviniana Rare Open vegetation & Dark green fritillary grassland Silver washed fritillary

Vegetation Descriptions In terms of the botanical resource, the disused railway line is quite diverse: a total of 104 plant species were observed during the present survey, including woody plants, herbaceous species, ferns, bryophytes and lichens (see accompanying Excel spreadsheet). No particularly rare species were encountered. This was not an exhaustive survey, and additional species would surely be found if greater efforts were made. The following five broad vegetation types can be distinguished. 1. Open herbaceous vegetation A sparse cover of annuals, biennials, perennials, occasional bryophytes and rarely lichens is confined to areas of bare ballast where little or no litter or soil has accumulated. These areas are likely to be very dry, nutrient-poor and unstable, although the gradual build-up of litter will tend to reduce these influences and allow the slow succession to a closed grassland sward. These areas can, however, be more rapidly lost to scrub as it encroaches from either side. 2. Flower-rich grassland A closed sward of often flower-rich neutral grassland has developed toward the edges of the open sections of the disused railway, grading out into the adjacent hedgerows. These grassland areas support a similar mix of plant species to the more open ballast areas, but with a greater proportion of perennials, including a variety of fairly robust grass species. The outer edges of the disused railway route may well be less drought-prone and more nutrient-rich than the ballast areas, as they tend to be more shaded, and may have developed somewhat deeper soils from the accumulation of litter from the adjacent hedgerows. Young scrub patches, particularly of bramble, are often apparent in these areas. 3. Species-poor herbaceous vegetation In some areas the central strip of herbaceous vegetation is dominated by very robust species such as nettles and thistles, with very few other plants. This is particularly the case where the central strip is very narrow, and the adjacent hedgerows and scrub form a canopy that casts a dense shade for much of the day. 4. Low scrub As noted above, low scrub of 30-200 cm height is often found encroaching from the margins across the open herbaceous zones, particularly from the eastern side. Bramble is the most common species, and sometimes forms almost complete cover from one hedgerow to the other, often with the total loss of herbaceous plants. Other encroaching woody species include dog rose, hawthorn and occasional blackthorn. 5. Dense scrub & hedgerows The hedgerows and scrub belts that flank the disused railway are generally continuous and are quite dense (between 3-8 metres deep), and of moderate height, being mostly 4-6 metres tall, with occasional young mature standard trees. The hedgerows are quite diverse; whilst typically dominated by hawthorn and blackthorn, with frequent dog rose, a number of other woody species are scattered along the route, including ash, aspen, buckthorn, crab apple, dogwood, English elm, English oak, field maple, goat willow, wild pear, wild privet, and rarely Midland hawthorn. Blackthorn, although abundant overall, is locally sparse in places.

Conclusions The disused railway at Greatmoor currently supports a mosaic of open, partially bare ground, fringing species-rich grassland, dense herbaceous vegetation, encroaching bramble scrub, and flanking dense mature hedgerows, with varying proportions of each along different sections of the route. The open herbaceous vegetation is botanically quite diverse, although with no particularly rare species, and the hedgerows and scrub are also quite species-rich, although dominated by hawthorn, blackthorn and dog rose. Together these different habitats and vegetation types provide potential breeding and foraging areas for a wide variety of invertebrates, in particular certain scarce butterfly and moth species. The railway line is likely to provide a valuable corridor for wildlife to move along within the agriculturally improved landscape that surrounds it, and may provide a ‘stepping stone’ between nearby nature reserves and other wildlife-rich sites. The open vegetation of the railway line is clearly becoming gradually encroached upon by adjacent scrub, and dense brambles often choke sections, although in large parts of the route there still remains a broad strip of open vegetation. It is likely that in the absence of active management of the scrub, over the next 20-30 years natural successional processes will cause much of the open areas to become dominated by dense scrub, although particularly infertile and drought-prone sections could remain open for far longer than this. Under such a scenario, while mature blackthorn would still provide good habitat for black hairstreak butterflies, the loss of herbaceous larval food-plant species to scrub encroachment would be likely to be detrimental to other dependent butterfly and moth species. It is possible, therefore, that active use of the route could help to maintain the open nature of the site. However, this would only be true if a significant part of the open area that is now present could be retained, or extended to one side or the other. Conversely, if much of the existing mature blackthorn that is present in the hedgerows were to be lost due to the construction of screening bunds and swale channels as part of the proposed development, it is quite possible that there would be a significant impact upon dependent black hairstreak populations. Species-rich hedgerows or scrub belts with an abundance of mature blackthorn exist along much of the route, and should be retained, where possible. Approximately centrally located broad bands of low-growing, species-rich herbaceous vegetation are also frequent along the route, and ideally much of these should also be retained. In addition, currently the hedges and scrub bands provide a substantial screen from surrounding land and properties along much of the route, and ideally these should not be significantly damaged. In order to minimise the ecological impacts of the access road design presented in the planning application submitted in October 2010, a number of measures, presented in the section below, should beconsidered by the road design engineers, and used in the revised and detailed design of the proposed access road.

Discussion – Potential Measures to Reduce Ecological Impacts of October 2010 Access Road Design In order to minimise the ecological impacts of the road scheme initially proposed in the original planning application (Ramboll Drawing Reference 7493/C/CR/210 - 222), a number of measures should be considered by the designing engineers. The incorporation of those measures that are technically feasibly into any revisions of the road design has the potential to substantially reduce or avoid identified impacts of the scheme. 1.

Are the proposed road dimensions the minimum that could safely be used, or could they be reduced in order to reduce damage to important vegetation?

2.

Could the road be off-set to one side or another in order to retain a significant width (e.g. 3-4 metres) of the existing open vegetation strips? If this is possible, then perhaps consider keeping the road to the shadiest side of the route, i.e. to the east side for much of the route, but swapping to the west side at the northern end. This might be of benefit both by retaining more of the drought-tolerant species of open habitats, and also by providing more basking places for reptiles and butterflies.

3.

What is the requirement for construction of screening bunds? Are these necessary where the existing hedgerow, proposed sound barriers and cutting or embankment combination already provide adequate landscape screen and noise attenuation?

4.

Could sufficient height & width of the scrub belts/hedgerows be retained, including standard trees present, so that they retain their screening function and biodiversity corridor function? What is the requirement for surface water drainage and could this be re-designed to minimise land-take? Where drains or swales are necessary, could they be constructed of ballast, to replace that lost as part of this work? This would help to minimise vegetation management. Existing ballast vegetation could be translocated to the new swale or drain.

5.

To what extent can construction of the road be planned and undertaken in order to minimise damage to adjacent herbaceous vegetation and hedgerows outwith the actual road footprint?

6.

What will happen to the brash arising from scrub clearance for the construction? Careful disposal of this will be necessary to avoid smothering important plants, e.g. there are some plants indicative of ancient woodland under parts of the scrub belts, see T61. It may also be used for habitat creation.

7.

Spray/runoff from muddy trucks could gradually add nutrients to the adjacent nutrientpoor ground, and this could lead to enrichment and loss of plant diversity on the flanking ground. Can this potential effect be managed through wheel washing prior to entering the access road or through design of the drainage system?