Chalk Carpet Scotopteryx Bipunctaria: East of England Survey in 2006 and 2007

Chalk Carpet Scotopteryx bipunctaria: East of England Survey in 2006 and 2007

S. Hearle

2009

Butterfly Conservation Report No. S09-44

Butterfly Conservation Company limited by guarantee, registered in England (2206468) Registered Office: Manor Yard, East Lulworth, Wareham, Dorset. BH20 5QP Charity registered in England and Wales (254937) and in Scotland (SCO392680)

Circulation List

Butterfly Conservation (Library)

Butterfly Conservation (Mark Parsons)

Natural England, Headquarters (David Sheppard)

Natural England, Headquarters (Library)

Natural England, Essex Team (Chris Gibson)

Natural England, Cambridgeshire Team (Tom Charman)

Natural England, Bedfordshire Team (Alex Nicholls)

Natural History Museum Library (Sharon Touzel)

Bedfordshire County Council (Jon Comont)

Wildlife Trust for Bedfordshire, Cambridgeshire, Northamptonshire and Peterborough – Cambridgeshire Office (Martin Baker)

Wildlife Trust for Bedfordshire, Cambridgeshire, Northamptonshire and Peterborough – Bedfordshire Office (Ed Turner)

Cambridge Green Belt Project (Iain Webb)

Hertfordshire Wildlife Trust (Steve Halton)

Cambridgeshire Moth Group (John Dawson)

Bedfordshire Moth Group (Andy Banthorpe)

Hertfordshire Moth Group (Colin Plant)

Cambridgeshire and Essex Branch Butterfly Conservation (Louise Bacon)

Hertfordshire and Middlesex Branch Butterfly Conservation (Liz Goodyear)

Bedfordshire & Northamptonshire Branch Butterfly Conservation (Peter Glenister)

Orwell Parish Council (Bob Bryant)

National Trust - Whipsnade (Ellen Dempster)

Cemex (Martin Lithgo)

Hearle, S., 2009. Chalk Carpet Scotopteryx bipunctaria: East of England Survey in 2006 and 2007. Butterfly Conservation, Wareham. (Butterfly Conservation Report No. S09-44).

Contents

1. Summary……………………………………………………………………………..… 1

2. Introduction……………………………………………………………………….….… 2

3. Methods…………………………………………………………………………..……. 2

4. Results………………………………………………………………………………..... 3

a) Sites with positive records for Chalk Carpet………………………………. 4

b) Former sites with negative records for Chalk Carpet…………………….. 14

5. Discussion and conclusions………………………………………….………………. 23

6. Recommendations……………………………………………………………………. 25

7. Acknowledgements…………………………………………………………………… 25

8. Bibliography……………………………………………………………………………. 26

9. Appendix 1: Summary of Chalk Carpet records…………………………………… 27

10. Appendix 2: Site photographs……………………………………………………… 28

Hearle, S., 2009. Chalk Carpet Scotopteryx bipunctaria: East of England Survey in 2006 and 2007. Butterfly Conservation, Wareham. (Butterfly Conservation Report No. S09-44).

1. Summary

The Chalk Carpet Scotopteryx bipunctaria is a distinctive moth that occurs very locally on calcareous sites in southern England and Wales. It is a Priority Species in the UK Biodiversity Action Plan. The moth has undergone a considerable national decline the reasons for which are not fully understood.

This report covers the discovery of the moth at four sites in Cambridgeshire and five sites in Bedfordshire. At several sites the moth was abundant. Five sites were either working or recent chalk quarries with significant areas of bare chalk.

Efforts to find the moth at former known sites in Cambridgeshire, Essex and Bedfordshire were unsuccessful possibly due to the more closed nature of the chalk grassland sward. Recording effort in the past has concentrated on re-visits to former sites.

There are recommendations for other promising sites to survey in the future, in particular extensive former chalk quarries at Steeple Morden in Cambridgeshire, Houghton Regis in Bedfordshire and Pitstone Quarry on the Hertfordshire border plus newly created areas of bare chalk such as the Baldock Bypass in Hertfordshire.

Conservation work for Chalk Carpet is likely to benefit the Small Blue butterfly cupido minimus which was found at 5 sites with Chalk Carpet. The presence of Small Blue at a site is also a good indicator that Chalk Carpet might be present.

1 2. Introduction

This report provides a summary of survey work for Chalk Carpet moth at 18 former and potential sites in the East of England Region during 2006 and 2007. The project received funding from Natural England through the Countdown 2010, Esmée Fairbairn Foundation and help from volunteer surveyors.

The Chalk Carpet moth has been the focus of Butterfly Conservation effort in the East of England Region following a positive record at a light trap in Harlton near Cambridge in 2003. The last record in Cambridgeshire prior to that had been at Fleam Dyke in 1973 despite searching by volunteers. Fleam Dyke has seen considerable scrub clearance over the last 10 years but the moth probably disappeared due to scrub encroachment in the past and the lack of bare chalk. In Essex the moth was last recorded at Grays Chalk Pit in 1984 and not since. In this survey potential new sites with extensive areas of bare chalk were surveyed. This included working chalk quarries.

The Chalk Carpet is a Priority Species in the UK Biodiversity Action Plan and as its name suggests is associated with bare chalk and areas of chalk grassland. The adult can be disturbed during the day and is sometimes seen flying around. It can also be caught after dark at light traps. The larvae feed on a wide range of leguminous plants including Common Bird’s-foot-trefoil Lotus corniculatus, Red Clover Trifolium pratense, White Clover T.repens, Black Medick Medicago lupulina and Horseshoe Vetch Hippocrepis comosa. This species is single-brooded. Eggs are laid in July and August. The larvae occur from late August until June the following year. They overwinter when still quite small; probably low down on the foodplant. The species pupates on the ground in June and July with the adults emerging in July and August.

3. Methods

All sites were visited during the day between 10am and 3pm in dry, sunny weather in the flight season for the moth. The area was surveyed using a large branch or net sweeping the ground in front disturbing moths so they could be followed and caught in a net for positive identification and then released. There are other day flying moths such as Shaded Broad-bar Scotopteryx chenopodiata that can initially appear similar to Chalk Carpet. Surveyors searched areas of bare chalk and scree on slopes at the sites visited as well as flatter areas.

The sites were not all visited each year and the date of the last record does not mean that the moth was necessarily absent or present in previous or subsequent years.

2 4. Results

Figure 1 illustrates the distribution of the Chalk Carpet moth in Eastern England and includes sites with positive records between 2006 and 2007. The location of former sites searched during this survey are also mapped with the exception of Grays Chalk Pit, Chafford Hundred in Essex.

Figure 1: Map showing location of Chalk Carpet moth sites in the East of England Region 2006-07 Extant sites blue and extinct sites red circles.

Site descriptions and results are grouped into occupied and former sites where surveys were negative. Data for each site are tabulated below, including location, conservation status, area, ownership, access, adult records, larval foodplants, habitats, presence of other local priority species and proximity to nearest site. A map of each site is provided although the extent of suitable habitat is not shown and can be quite a small proportion of the site. The history of management for each site is provided as well conservation recommendations and survey notes.

3 a) Sites with positive records for Chalk Carpet

1. East Pit, Cherry Hinton (Cambridgeshire)

District Cambridge City Grid Reference TL 483557 Conservation SSSI Ownership Wildlife Trust Status Approx. Area 12 hectares Access Limited public access Date of Last 12 July 2007 Adult Count 10 Record Foodplants Common Bird’s- Habitats Present Chalk grassland, foot-trefoil bare chalk Other Local None Distance to Next Barrington Quarry Priority Species Site 14km

Site Management History This site is a former chalk quarry abandoned since 1940 with plenty of bare chalk including steep cliffs. There has been some management to remove Buddleia and illegal mountain biking has helped keep the site open. The Wildlife Trust has recently agreed to manage this site. Conservation/Management Requirements Large areas of Buddleia and other scrub should be cleared. Scarification or bulldozing to maintain areas of bare chalk will be needed in the future. Survey Notes There are also records of the moth in 2005 and 2006 as well as historic records for the moth in the general area. A regular moth trapper lives less than 1.5 km away but never caught the moth in his trap. Surveyors also visited West Pit (Wildlife Trust reserve) on the other side of the road on 12 July 2007 but no Chalk Carpet were found. West Pit does have more established chalk grassland and is maintained by mowing. East Pit is 14 km from the other Chalk Carpet populations at Orwell and Barrington.

4 2. Orwell Pit (Cambridgeshire)

District South Grid Reference TL 364506 Cambridgeshire Conservation SSSI Ownership Orwell Parish Status Council Approx. Area 1.8 hectares Access Open public access Date of Last 10 July 2006 Adult Counts 4 Record Foodplants Common Bird’s-foot- Habitats Present Chalk grassland, trefoil, Horseshoe bare chalk Vetch Other Local None Distance to Next Barrington Quarry Priority Species Site 3km

Site Management History This former chalk pit is one of the smallest known sites with Chalk Carpet in Eastern England but it is 3 km from a large site at Barrington Quarry. Large areas of scrub were cleared in 2000 when this site was also fenced and sheep grazing introduced. Conservation/Management Requirements No additional management required at present. Bare chalk associated with the caves and paths on the upper slopes are maintained by the activities of people and grazing animals. Survey Notes The moth is usually encountered in the bare chalk and scree on the south west facing bank. Survey effort elsewhere on the site has not been successful. There are public footpaths across the site.

5 3. Barrington Quarry (Cambridgeshire)

District South Grid Reference TL 399511 Cambridgeshire Conservation Geological SSSI Ownership Cemex Status Approx. Area 97 hectares Access No public Access Date of Last 16 July 2007 Adult Counts 2 Record Foodplants Common Bird’s- Habitats Present Active chalk foot- trefoil quarry, bare chalk Other Local Small Blue Distance to Next Orwell Pit 3km Priority Species (single record only) Site

Site Management History This site has been a large working chalk quarry for at least 50 years with abundant areas of bare chalk. Quarrying work ceased in 2008 and long term plans for the site are still to be explored. Conservation/Management Requirements No management required at present and this site has the potential to support the moth for decades in the future especially if the quarry is not restored with topsoil and tree planting. Survey Notes Only a small area of the quarry was sampled on 16 July 2007. It is likely that a large and extensive population occurs at this site as the moth has been recorded at nearby Harlton village and along the adjacent Haslingfield Road Verge.

6 4. Haslingfield Road Verge (Cambridgeshire)

District South Grid Reference TL398509 Cambridgeshire Conservation None Ownership Road verge Status Approx. Area 2 hectares Access Along road edge Date of Last 9 July 2006 Adult Counts 1 Record Foodplants Common Bird’s- Habitats Present Chalk grassland foot- trefoil, Red Clover Other Local None Distance to Next Barrington Quarry Priority Species Site 0.5km

Site Management History The roadside verge is not protected and provides a narrow corridor of habitat between the arable field, road and Barrington Quarry. It is mown twice a year by the highway authority. There is only limited areas of bare ground along the field edge. Conservation/Management Requirements To maintain chalk grassland habitat and perhaps consider the creation of bare ground where the grass has become coarse and rank. Survey Notes It is possible that the moth recorded here was a wanderer from the Barrington Quarry nearby and ultimately dependent on the habitat there for long term survival. This site is easy to access but care is needed as it is directly next to a busy road.

7 5. Totternhoe Quarry (Bedfordshire)

District South Bedfordshire Grid Reference SP986225 District Council Conservation SSSI Ownership Wildlife Trust Status Approx. Area 13 hectares Access Public access Date of Last 2007 Adult Counts Abundant 10++ Record Foodplants Common Bird’s- Habitats Present Chalk grassland, foot-trefoil, chalk scrub and Horseshoe Vetch bare chalk Other Local Small Blue. Distance to Next Totternhoe Knolls Priority Species Chalkhill Blue. Site 0.5 km Duke of Burgundy

Site Management History This site was quarried for chalk in the past with the uneven terrain giving a variety of aspects. Scrub clearance and some limited grazing on site but quite a lot of bare chalk remains. Conservation/Management Requirements Continue scrub management and maintenance of bare ground. Survey Notes A detailed study on four butterflies (Duke of Burgundy, Chalkhill Blue, Dingy Skipper and Small Blue) is taking place through the SITA funded ‘Dukes and Blues Project’ run by The Bedfordshire Wildlife Trust. This is one of only a few sites that supports Chalkhill Blue, Small Blue butterflies and Chalk Carpet. Ed Turner has also recorded the moth along the bare chalk cliff along the field boundary opposite the Quarry. This site and the neighbouring site Totternhoe Knolls are well visited by volunteer surveyors and a weekly butterfly transect is walked.

8 6. Totternhoe Knolls (Bedfordshire)

District South Bedfordshire Grid Reference SP979220 District Council Conservation SSSI, LNR, SAM Ownership Bedfordshire Status County Council Approx. Area 4 hectares Access Public access Date of Last 18 August 2006 Adult Counts 5 Record Foodplants Common Bird’s- Habitats Present Chalk grassland, foot- trefoil, chalk scrub and Horseshoe Vetch bare chalk Other Local Chalkhill Blue Distance to Next Totternhoe Quarry Priority Species Site ½ km

Site Management History This site has been quarried since medieval times and spoil heaps have developed into chalk grassland. A large area of scrub has been cleared in the last 5 years and sheep grazing introduced. This site is managed by National Trust in partnership with Bedfordshire Wildlife Trust. Conservation/Management Requirements Scrub clearance and sheep grazing to continue with consideration given to creating more bare ground where possible. However, this site is a Scheduled Ancient Monument so this may be more difficult. Survey Notes This site is directly next to Totternhoe Quarry. This site is well visited by volunteer surveyors.

9 7. Sundon Quarry (Bedfordshire)

District South Bedfordshire Grid Reference TL040273 District Council Conservation SSSI Ownership Private Status Approx. Area 26 hectares Access Some public footpaths Date of Last 12 July 2006 Adult Counts 8 Record Foodplants Common Bird’s- Habitats Present Chalk grassland, foot- trefoil, chalk scrub, Horseshoe Vetch woodland and bare chalk Other Local Small Blue, Dingy Distance to Next Barton Hills 5 km Priority Species Skipper, Chalkhill Site Blue and Grizzled Skipper

Site Management History A large chalk quarry abandoned for at least 20 years with several dumped cars and illegal motorcycling activities. There is a large amount of bare chalk, steep slopes and uneven terrain giving a variety of aspects. There is very little formal management at this site at present. Conservation/Management Requirements Maintain areas of bare chalk and open chalk grassland.

Survey Notes Large numbers of Chalk Carpet are present at this site according to local surveyors over many years but this is not backed up by formal records. This site also supports Small Blue and Dingy Skipper. Natural England has recognised the value of bare ground here in their condition assessment and that an upper and lower limit for bare ground should be recorded as an attribute i.e. 10-50%.

11 8. Barton Hills (Bedfordshire)

District South Bedfordshire Grid Reference TL 090298 District Council Conservation SSSI, NNR Ownership Natural England Status Approx. Area 47 hectares Access Public access Date of Last 31 July 2005 Adult Counts 1 Record Foodplants Bird’s foot Trefoil, Habitats Present Chalk grassland, Horseshoe Vetch chalk scrub/woodland Other Local Chalkhill Blue, Distance to Next Sundon Quarry 5 Priority Species Dingy Skipper Site km

Site Management History This site was quarried for chalk in the past and has a variety of slopes and aspects with areas of long and short grassland. There is some bare chalk along hillsides in the smaller valleys where rabbits are well established. The site is grazed by sheep. Conservation/Management Requirements Consider options for creating and maintaining areas of bare chalk on slopes. Survey Notes Only one Chalk Carpet recorded here suggesting a very low population that may disappear without further management to create bare ground. This is a large site but with only a very small area of suitable habitat for Chalk Carpet where there is rocky chalk on steep slopes with lots of rabbit activity.

12 9. Kensworth Quarry (Bedfordshire)

District South Bedfordshire Grid Reference TL 013200 District Council Conservation Geological SSSI Ownership Cemex Status (part) Approx. Area 131 hectares Access Some public access Date of Last 18 July 2007 Adult Counts 5 Record Foodplants Common Bird’s- Habitats Present Bare chalk, foot- trefoil, White restored grassland Clover and scrub Other Local Small Blue Distance to Next Totternhoe Quarry Priority Species Site 5 km

Site Management History A working chalk quarry for the past 50 years or more with a further 30 years to go at least. There are vast areas of bare chalk in the working quarry. Large areas have been restored to woodland and grassland. Conservation/Management Requirements In the nature reserve area: exclude sheep from bare chalk plots and create new areas of bare soil every five years. Consider expanding these areas and removing some restored vegetation. In quarry area: ensure that future restoration work will include large areas of bare chalk. Survey Notes This site also supports a large population of Small Blue. Only a small area of the quarry restored as a nature reserve was surveyed. The main areas where Chalk Carpet was found were fenced off and did not have top soil applied and ‘restored’. These areas were left to show the geological layers and are now a carpet of Kidney Vetch and Common Bird’s- foot-trefoil.

13 b) Former sites with negative records for Chalk Carpet

1. Fleam Dyke (Cambridgeshire)

District South Grid Reference TL 550540 Cambridgeshire Conservation SSSI, SAM Ownership Jesus College Status Approx. Area 11 hectares Access Some public access Date of Last 1972 Adult Counts 0 Record Foodplants Common Bird’s- Habitats Present Chalk grassland, foot- trefoil, Red chalk scrub Clover, Horseshoe Vetch Other Local Chalkhill Blue Distance to Next East Pit 7km Priority Species Site

Site Management History The site has seen considerable scrub clearance over the last 10 years but the moth probably disappeared due to scrub encroachment in the past and the lack of bare chalk. Conservation/Management Requirements None as the moth is absent. The nearest site is at East Pit, 7 kilometres away so re- colonisation is unlikely. The site is also a Scheduled Ancient Monument and the creation of bare ground will always be difficult. Survey Notes This site also supports a small population of Chalkhill Blue. A weekly butterfly transect walk has also failed to record the moth in 2006 and 2007.

14 2. Wilbraham Quarry (Cambridgeshire)

District South Grid Reference TL 565546 Cambridgeshire Conservation None Ownership Brockhill Contracts Status Ltd Approx. Area 3 hectares Access No public cccess Date of Last None Adult Counts 0 Record Foodplants Red Clover Habitats Present Bare chalk Other Local None Distance to Next East Pit 8 km Priority Species Site

Site Management History Working chalk quarry for at least 50 years within 1 kilometre of Fleam Dyke a former site for Chalk Carpet in 1972. This Quarry is almost entirely bare chalk with vertical cliffs and limited vegetation around the top of the cliff. Conservation/Management Requirements No recommendations. This site is likely to be filled with inert waste and restored for agriculture. Survey Notes No Chalk Carpet see during visits walking along the field edge at the top on 17 July 2006 and 19 July 2007. There is very little vegetation in the quarry.

15 3. Devil’s Dyke (Cambridgeshire)

District East Grid Reference TL 617616 Cambridgeshire Conservation SSSI, SAM Ownership Jockey Club Status Approx. Area 11 hectares Access Public access Date of Last 1961 Adult Counts 0 Record Foodplants Horseshoe Vetch Habitats Present Chalk grassland Common Bird’s- ,foot- trefoil Other Local Dingy Skipper, Distance to Next East Pit 12 km Priority Species Chalkhill Blue Site

Site Management History There is a long history of mowing and scrub clearance to maintain chalk grassland along this steep embankment. Sheep grazing has been introduced along some sections. Old photographs suggest that this site had much more bare chalk in the past than it does today. Conservation/Management Requirements This site would probably benefit from a larger percentage of bare ground but as it is a Scheduled Ancient Monument and Chalk Carpet is no longer present this is unlikely to be achievable. Survey Notes A weekly butterfly transect walk has failed to record the moth between 2005 and 2008.

16 4. Therfield Heath (Hertfordshire)

District North Hertfordshire Grid Reference TL 335400 Conservation SSSI, LNR Ownership Conservators of Status Therfield Heath Approx. Area 169 hectares Access Some public access Date of Last 1961 Adult Counts 0 Record Foodplants Horseshoe Vetch, Habitats Present Chalk grassland, Common Bird’s- chalk scrub and foot- trefoil woodland Other Local Chalkhill Blue Distance to Next Orwell Pit 12 km Priority Species Site

Site Management History There is a long history of management to maintain chalk grassland at this site and sheep grazing was introduced in 2005. There are only small pockets of bare chalk remaining on site. Conservation/Management Requirements None as the moth is absent. The nearest site is Orwell Pit 12 km away and re- colonisation is probably unlikely without large areas of bare chalk. Notes This site supports a large population of Chalkhill Blue butterfly. A full butterfly transect is walked on this site by Alan Beale and no Chalk Carpet were seen between 2005 and 2008. The heath now has very limited areas of open bare chalk with a generally closed chalk grassland sward.

17 5. Hexton Chalk Pit (Hertfordshire)

District North Hertfordshire Grid Reference TL107299 Conservation CWS Ownership Hertfordshire Status Wildlife Trust Approx. Area 8 hectares Access Public access Date of Last 6 July 2001 Adult Counts 0 Record Foodplants Horseshoe Vetch, Habitats Present Chalk grassland, Common Bird’s- chalk scrub foot- trefoil Other Local Chalkhill Blue, Distance to Next Barton Hills 1 km Priority Species Dingy Skipper Site

Site Management History There is a long history of management by scrub clearance. Fence in place for grazing. New management plan in preparation 2008. Conservation/Management Requirements Maintain existing chalk grassland and areas of bare chalk. Survey Notes This site is well visited by volunteers and all survey visits for Chalk Carpet were negative.

18 6. Grays Chalk Pit, Chafford Hundred (Essex)

District Thurrock Borough Grid Reference TQ 609789 Council Conservation SSSI Ownership Essex Wildlife Status Trust and others Approx. Area 17 hectares Access Some public access Date of Last 1984 Adult Counts 0 Record Foodplants None recorded Habitats Present Chalk scrub Other Local None Distance to Next Possibly sites in Priority Species Site Kent

Site Management History Grays Chalk Pit is an SSSI in the Chafford Hundred site of 240 hectares most of which is now residential development on the remains of a large complex of worked out chalk quarries. Grays Chalk Pit itself is now largely overgrown with trees and shrubs and no longer has bare chalk. There are some inaccessible chalk cliffs within the development but even these will soon be overgrown with shrubs and climbing plants. Conservation/Management Requirements None as the moth is absent and unlikely to re-colonise without the creation of large areas of bare chalk which seems unlikely in this area of dense residential development. Survey Notes On 19 July 2007 no moths were found during 2 hour visit. It is possible that some inaccessible quarry or area of steep chalk cliff in the vicinity might support the moth.

19 7. Dunstable Down (Bedfordshire)

District South Bedfordshire Grid Reference TL105200 District Council Conservation SSSI Ownership National Trust Status Area 38 hectares Access Some public approximately access Date of last record 1981 Adult Counts 0 Foodplants Horseshoe Vetch, Habitats Present Chalk grassland, Common Bird’s- chalk scrub and foot-trefoil woodland Other Local Chalkhill Blue Distance to next Kensworth Quarry Priority Species Dingy Skipper site 1km

Site Management History This large area of chalk grassland has well established species-rich chalk grassland and areas of very short sheep grazed turf. Bare chalk is restricted to small patches mainly on steeper slopes. A large area of scrub was cleared in the Pascomb Pit area in 2007 and there is a lot of bare ground in this area but it is mainly soil rather than chalk and the bare ground may be short-lived as ruderal plants invade. Conservation/Management Requirements Explore option for creating more areas of bare chalk especially in the Pascomb Pit area of the site. There is a good chance that Chalk Carpet could re-colonise this site. Survey Notes Site visit on 18 July 2007 for two hours and none seen. Small Blue has also recently disappeared from this site. The nearest known site for Chalk Carpet is Kensworth Quarry 1 km away. Another group of sites at Totternhoe is 2.5 km in the other direction.

20 8. Whipsnade Down (Bedfordshire)

District South Bedfordshire Grid Reference TL000186 District Council Conservation SSSI Ownership National Trust Status Area 13 hectares Access Some public approximately access Date of last record 1981 Adult Counts 1 Foodplants Horseshoe Vetch, Habitats Present Chalk grassland, Common Bird’s- chalk scrub and foot- trefoil woodland Other Local Duke of Burgundy, Distance to next Kensworth Quarry Priority Species Grizzled Skipper site 1 km

Site Management History This large area of chalk grassland has well established species-rich chalk grassland and areas of very short sheep grazed turf. Bare chalk is restricted to small patches mainly on steeper slopes. Conservation/Management Requirements Explore option for creating more areas of bare chalk. Survey Notes Site visit on 18 July 2007 for two hours and none seen. This site also supports a large population of Chalkhill Blue and Duke of Burgundy butterflies. Small Blue has also recently disappeared from this site. The nearest known site for Chalk Carpet is Kensworth Quarry 1.25 km away. Another group of sites at Totternhoe is 2.5 km in the other direction.

21 9. Aldbury Nowers (Hertfordshire)

District Dacorum Grid Reference SP349165 Conservation SSSI Ownership Hertfordshire Status Wildlife Trust Approx. Area 19 hectares Access Some public access Date of Last 1956 Adult Counts 0 Record Foodplants Horseshoe Vetch, Habitats Present Chalk grassland, Common Bird’s- chalk scrub and foot trefoil woodland Other Local Grizzled Skipper Distance to Next Kensworth Quarry Priority Species Site 12 km

Site Management History This site has a large area of chalk grassland with well established species-rich chalk grassland. Extensive habitat management took place in 2007 to clear trees and scrub and create large areas of bare chalk. The site is also grazed by sheep. Conservation/Management Requirements Maintain some area of bare chalk. Continue to monitor site for Chalk Carpet and Small Blue re-colonisation. Survey Notes Site visit on 18July 2007 for one hour and none seen. This site is within 2 km of Pitstone Chalk Quarry. It is known that Pitstone Chalk Quarry supports Small Blue butterfly and quite possibly would support Chalk Carpet.

22 5. Discussion and conclusions

The Chalk Carpet is a distinctive moth to monitor during day time searches in the flight period. Volunteers can be shown how to recognise the moth although a single visit to a site may fail to detect the moth especially if it occurs at low numbers. At sites where the moth was found it was usually in areas of bare and crumbling chalk. Disturbing the ground ahead with a branch certainly helped to locate moths and at some sites the moth was found within the first ten minutes of searching. The moth settled again quickly after disturbance usually on bare chalk.

The moth was discovered at four sites in Cambridgeshire and five sites in Bedfordshire. In some cases, especially working quarries, these represent previously unrecorded populations and it is quite possible that the moth had been present at such sites for many years. At several sites the moth was abundant. All of the sites, except one were either working or recent chalk quarries with significant areas of bare chalk on slopes or in the case of one site, directly next to a large working quarry. This survey has indicated that working chalk quarries are a preferred habitat for this moth due to the abundance of bare chalk.

Efforts to find the moth at nine former known sites in Cambridgeshire, Essex and Bedfordshire were unsuccessful possibly due to the more closed nature of the chalk grassland sward and lack of bare chalk.

At some sites with steep cliffs, areas of bare chalk are inaccessible or dangerous to access. It is possible that the moth may still occur on a site but not be recorded from survey work in flatter areas with a closed sward. At Orwell Pit the moth is easily encountered around the chalk caves on the upper slopes but not elsewhere on the site.

Repeated negative survey results especially from butterfly transect walkers on former sites strongly suggest that the moth is no longer present. These sites also had limited areas of bare chalk compared to occupied sites. Re-colonisation at some former sites might be possible if suitable management to create bare ground can be implemented and if an occupied site is nearby. Aldbury Nowers is a former site where significant scrub clearance and earth moving took place in 2007 to place enriched top soil underneath chalk. It is possible that the moth might re-colonise the site in the future if bare ground is maintained as a large chalk quarry is less than 2 km away (Pitstone Quarry but outside the East of England Region), although the mobility of the species is not well known. Potential for creating bare ground at sites with archaeological interest such as Devil’s Dyke and Fleam Dyke will be limited.

The large new road cutting through bare chalk at Baldock in Hertfordshire is 15 km from Barrington Chalk Quarry and Orwell Pit and it is possible that the moth might manage to colonise the site in the future.

Chalk Carpet and Small Blue butterfly are often found at the same sites. Small Blue was found at 5 sites with Chalk Carpet and is also a UKBAP Priority Species. Conservation work for Chalk Carpet is likely to benefit Small Blue.

Many former working chalk quarries are maintained in a suitable condition for Chalk Carpet by natural erosion. Broken soils on chalk grassland create a suitably warm microclimate for caterpillars. However scrub encroachment is always a possible issue and clearance may be needed to ensure that sites do not become overgrown.

23 Some periodic soil disturbance or scrapes where the top layer is removed may also be beneficial.

Natural England have recognised the value of bare ground at Sundon Quarry and recommended that an upper and lower limit for bare ground should be recorded as an attribute ie 10-50%. It would be helpful if this was recognised at other chalk grassland SSSIs and County Wildlife Sites with Chalk Carpet as well.

The positive results indicate that there are undetected populations of this moth awaiting discovery, at least in the counties currently known to support the moth and with significant areas of bare chalk. The presence of Small Blue at a site is also a good indicator that Chalk Carpet might be present and could lead to the discovery of new colonies in the region. It is therefore likely that former working quarries at Houghton Regis and Arlesey in Bedfordshire and Pitstone Quarry on the Hertfordshire Buckinghamshire border would support colonies of the moth.

24 6. Recommendations a) Survey and monitoring

Encourage regular monitoring on known sites.

Revisit Aldbury Nowers in Hertfordshire where considerable scrub clearance and creation of bare chalk has taken place in 2007.

Encourage Hertfordshire County Council to include Chalk Carpet in their monitoring surveys at the new Baldock Bypass.

Arrange access permission and undertake survey work at Houghton Regis, Aresley, Pitstone and Steeple Mordan chalk quarries.

Identify sites with Small Blue for Chalk Carpet survey visits. b) Site management

Encourage management that periodically creates bare chalk area on known sites. This type of management is also likely to benefit Small Blue butterfly if it is present on the site or nearby.

Ensure that restoration programmes for chalk quarries include maintenance of bare ground habitats and avoid tree planting.

Continue scrub clearance programmes to keep sites open and encourage chalk grassland flora.

An upper and lower limit for bare ground should be recorded as an attribute (i.e. 10-50%) on SSSIs and County Wildlife Sites with Chalk Carpet.

7. Acknowledgements

Thanks to all the volunteers who helped with the survey work including: Ed Turner, Alan Beale, Vince Lea, Val Perrin, Louise Bacon, Paul Stebbings, J.E.Childs, Peter Glenister and John Dawson.

Thanks to all the landowners for access and assistance including John Drayton and Martin Lithgo at Cemex.

25 8. Bibliography

Goodey, B., 2004. The Moths of Essex. Lopinga Books.

Plant, C. W., 2008. The Moths of Hertfordshire. Hertfordshire Natural History Society, Cravitz.

Waring, P., 1999. Review of Nationally Scarce and Threatened Macromoths of Great Britain. Unpublished report for Joint Nature Conservation Committee.

Waring, P., Townsend, M., & Lewington, R., 2003. Field Guide to the Moths of Great Britain and Ireland. British Wildlife, Rotherwick.

26 9. Appendix 1: Summary of Chalk Carpet records

Chalk Carpet Records 2005-2007

Date County Site Name Grid Ref Number Recorder

11.7.05 Cambs Orwell Pit TL364506 5 Sharon Hearle 31.7.05 Beds Barton Hills TL092295 2 J. E. Childs

09.7.06 Cambs Haslingfield Verge TL398509 1 Sharon Hearle 10.7.06 Cambs Orwell Pit TL364506 4 Sharon Hearle 10.7.06 Cambs East TL484556 5 Sharon Hearle 12.7.06 Beds Sundon Quarry TL040273 8 Sharon Hearle 31.7.06 Beds Totternhoe Cliff SP988219 1 Ed Turner 31.7.06 Beds Totternhoe Cliff SP989220 1 Ed Turner 31.7.06 Beds Totternhoe Cliff SP990223 1 Ed Turner 31.7.06 Beds Totternhoe Cliff SP990222 1 Ed Turner 04.8.06 Beds Totternhoe Quarry SP988224 1 Ed Turner 06.8.06 Beds Totternhoe Quarry SP987224 1 Ed Turner 09.8.06 Beds Totternhoe Cliff SP987219 1 Ed Turner 09.8.06 Beds Totternhoe Cliff SP988219 1 Ed Turner 15.8.06 Beds Totternhoe Quarry SP987225 1 Ed Turner 15.8.06 Beds Totternhoe Quarry SP987224 1 Ed Turner 16.8.06 Beds Totternhoe Quarry SP984223 1 Ed Turner 16.8.06 Beds Totternhoe Quarry SP983223 1 Ed Turner 18.8.06 Beds Totternhoe Knolls SP978221 1 Ed Turner 18.8.06 Beds Totternhoe Knolls SP977221 1 Ed Turner

12.7.07 Cambs East Pit TL483557 10 Sharon Hearle 16.7.07 Cambs Barrington Quarry TL399511 2 Sharon Hearle 18.7.07 Beds Kensworth Quarry TL013200 5 Sharon Hearle 19.7.07 Cambs East Pit TL482556 5 2007 Beds Totternhoe Quarry SP986225 10+ Ed Turner

27 10. Appendix 2: Site photographs

Orwell Pit, Cambridgeshire

Kensworth Quarry, Bedfordshire Restored area and bare ground square in foreground with working quarry in the background

Barrington Quarry, Cambridgeshire