MOLE VALLEY NATURAL HISTORY AUDIT BUTTERFLIES
MOLE VALLEY NATURAL HISTORY AUDIT BUTTERFLIES
MOLE VALLEY NATURAL HISTORY AUDIT BUTTERFLIES
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Mole Valley Agenda 21 - Nature Conservation Sub-Group ©<br />
<strong>MOLE</strong> <strong>VALLEY</strong> <strong>NATURAL</strong> <strong>HISTORY</strong> <strong>AUDIT</strong><br />
<strong>BUTTERFLIES</strong><br />
Compiled by Gail & Stephen Jeffcoate
Butterfly Indicator Species for Mole Valley<br />
Three butterfly species have been chosen as indicator species for Mole Valley. They are:<br />
Silver-spotted Skipper (Hesperia comma). This is a species of both local and national importance (It<br />
is a Red Data Book Species). One of the largest metapopulations in Britain exists along the North<br />
Downs between Gomshall in the west and Reigate in the east and most of the habitat patches within this<br />
population are in the Mole Valley area. The Silver-spotted Skipper is on the northern edge of its range<br />
in southern Britain and has a very limited distribution, with colonies in the Chilterns, South Downs,<br />
Wiltshire and Dorset in addition to the Surrey population. It needs higher temperatures in which to<br />
breed than any other British butterfly and can only survive on a short sparse sward on south facing<br />
slopes of chalk grassland. Adults are relatively mobile (up to about 5km) and have a high dispersal rate.<br />
As most suitable habitat patches in the area are less than 0.5 hectares in size this means that a number of<br />
such patches must remain in existence for the insect to survive. Loss or degeneration of habitat patches<br />
below a critical level would result in the loss of the entire Surrey population. NB rabbit populations are<br />
in some cases beneficial to the species as rabbit grazing keeps the sward in the right condition but<br />
current very high rabbit populations are in some places damaging the habitat by overgrazing. If<br />
significant changes in rabbit populations occur, monitoring of the effect on Silver-spotted Skipper<br />
colonies will be needed.<br />
Marbled White (Melanargia galathea). This is a grassland species requiring longer sward than the<br />
Silver-spotted Skipper. It has spread slowly along the downs and is now much more widespread than it<br />
was 50 years ago. In Surrey it occured only on chalk grassland up to 1995 but it now appears to be<br />
spreading to other types of grassland and in 1996 has been seen in the Holmwood - Newdigate area.<br />
Monitoring of any further spread will be of great interest.<br />
White Admiral (Ladoga camilla). A woodland species more tolerant of shady conditions than most<br />
butterfly species the White Admiral has spread through Surrey woods in the 20th Century. It will be a<br />
good candidate for monitoring in the 21st Century as populations may change in response to different<br />
methods of woodland management and/or to climatic changes.<br />
For each of these species a 1995 county distribution map is available on a 1km scale. A list of sites in<br />
Mole Valley has been drawn up for each. All three are easily identified in the field. Other local species<br />
which should be monitored in future are: Dingy Skipper, Grizzled Skipper, Green Hairstreak, Brown<br />
Hairstreak, Small Blue, Adonis Blue, Brown Argus, Chalkhill Blue, Purple Emperor, Dark Green<br />
Fritillary, Silver-washed Fritillary and Wall Brown. Current records are held by Gail Jeffcoate and<br />
Surrey Wildlife Trust.
Mole Valley Agenda 21, Nature Conservation Sub-Group<br />
<strong>MOLE</strong> <strong>VALLEY</strong> <strong>NATURAL</strong> <strong>HISTORY</strong> <strong>AUDIT</strong><br />
<strong>BUTTERFLIES</strong>: Distribution and Status 1995/6<br />
Species:<br />
Silver-spotted Skipper<br />
It is difficult to separate populations of this species, which inhabits a number of small patches of<br />
suitable habitat along the downs, with movement of adults between patches. The Mole Gap probably<br />
acts as a barrier which few individuals cross, with metapopulations on either side. The species is<br />
vulnerable to loss of habitat; these losses may not be detected without careful monitoring by experts<br />
familiar with the requirements of the butterfly, but if available habitat were to fall below a critical level<br />
the entire metapopulation could die out very rapidly.<br />
Codes indicate maximum numbers seen on a single visit: A=1, B=2-9, C=10-29, D=30-99, E=100+.<br />
In 1995/6 the species was breeding in the following places:<br />
Population to west in Guildford Borough at Hackhurst and Colekitchen.<br />
White Downs area. National Trust. (Includes Blatchford Down TQ103487, Old Simms Field<br />
TQ105486, Old Plantation TQ107486, Chalk Quarry to east of road TQ114486, Great Down<br />
TQ117488, Chalkpit Field TQ119489, Wholecombe TQ123492, Lamb Leys TQ124495, Ranges<br />
TQ126495).<br />
Numbers up to C per visit. Currently very heavy rabbit grazing is rendering much Festuca ovina<br />
unsuitable even for this short turf specialist and there is potential for increases if rabbit numbers<br />
decrease, for instance due to Viral Haemorrhagic Disease.<br />
Denbies Hillside National Trust. Small populations in the Big Field TQ135500 (B-C), odd individuals<br />
seen in the Brow TQ146502 and Secretary's Field TQ149502.<br />
Box Hill National Trust. strong populations (C-D) on all grassland areas on north side of Hill, where<br />
Festuca sward is common. Smaller populations (A-B) on Viewpoint slopes and Dukes on the south side,<br />
where there is less Festuca currently in suitable condition.<br />
Mickleham Downs National Trust. TQ180535. Small population (B).<br />
Headley Warren TQ190538 (Private). Medium-sized population in Downs Field (C).<br />
Headley Heath, Chalk Slope area National Trust. TQ195533. Small population in South Paddock and<br />
on Terraces (B).<br />
Brockham Warren TQ198512. SCC. Good population (C) on old chalk workings.<br />
Betchworth Quarry TQ205155 Privately owned landfill area. Unsurveyed population on small<br />
patches of grassland, some inaccessible.<br />
Dawcombe Nature Reserve TQ215525. Currently owned by Smith Kline Beecham and managed by<br />
Surrey Wildlife Trust. Medium population (C) breeding mainly in the two compartments (known as A<br />
and B) at the north end of the reserve.<br />
Buckland Hills TQ228525-TQ233523. Privately owned by Buckland Estates. Population currently low<br />
due to excessive rabbit grazing in parts, and threatened in parts due to scrub/tree growth. Most<br />
threatened part of the Surrey SSS population.<br />
Juniper Hill TQ237520. NT. Population currently low due to excessive rabbit grazing.<br />
Mole Place TQ237522. Small area private land above Juniper Hill. Small pop. (B).<br />
Further population on Colley Hill to East, in Reigate & Banstead Borough.
Mole Valley Agenda 21, Nature Conservation Sub-Group<br />
<strong>MOLE</strong> <strong>VALLEY</strong> <strong>NATURAL</strong> <strong>HISTORY</strong> <strong>AUDIT</strong><br />
<strong>BUTTERFLIES</strong>: Distribution and Status 1995/6<br />
Species:<br />
Marbled White<br />
Codes indicate maximum numbers seen on a single visit: A=1, B=2-9, C=10-29, D=30-99, E=100+.<br />
White Downs. National Trust. Areas as for Silver-spotted Skipper. Numbers currently low due to<br />
excessive rabbit grazing, with A, B or C seen per visit. Numbers likely to increase if lower rabbit<br />
populations lead to taller sward.<br />
Denbies Hillside. National Trust. Found on all the grass compartments. Sward currently undergoing<br />
changes due to scrub removal, pony grazing, fluctuating rabbit populations. Marbled White populations<br />
generally strong with C or D seen per visit to most compartments. Higher numbers (E) may be seen in<br />
Steers Field, adjoining NT Car Park at TQ142503<br />
Box Hill National Trust. Can be found on all grass compartments. Strong populations on south slopes<br />
(Viewpoint slopes, Dukes) with D or E per visit on each. Lower numbers on the northern areas.<br />
Mickleham Downs TQ180535. National Trust. (C) -on grassland at top of slope.<br />
Cherkley Wood TQ187542, TQ 183547. Private. (C).<br />
Headley Warren TQ190538. Private. Up to C per compartment at present. The main grassland areas<br />
are currently very heavily rabbit grazed and Marbled White numbers can be expected to rise if sward<br />
height increases.<br />
Headley Heath, Chalk Slope Area National Trust. TQ195533. Small population. (B).<br />
Brockham Warren. SCC. TQ198512. Small population. Most grass too short. (A/B).<br />
Dawcombe Nature Reserve. TQ215525. Has become established in last 2-3 years, with numbers seen<br />
rising each year. In 1996 up to 20-30 seen per visit over whole site.<br />
Mole Place Private. TQ237522. Marbled White not seen here until 1995 (B). By 1996 well established<br />
(30 seen on one visit).<br />
Claypit on south side of Inholms Lane, North Holmwood. TQ175473. B seen 1996.<br />
The Marbled White has not been recorded from the Betchworth Quarry or Buckland Hills areas in<br />
1995/6, but is probably present in low numbers, and could increase if rabbit levels decrease.<br />
Single specimens seen in 1995/6 at: Polesden Lacey (NT) TQ182522; Hammonds Copse (field<br />
adjoining woodland) TQ 213442; on rough ground on north side of Trig Street, west of Newdigate,<br />
TQ190418
Mole Valley Agenda 21, Nature Conservation Sub-Group<br />
<strong>MOLE</strong> <strong>VALLEY</strong> <strong>NATURAL</strong> <strong>HISTORY</strong> <strong>AUDIT</strong><br />
<strong>BUTTERFLIES</strong>: Distribution and Status 1995/6<br />
Species:<br />
White Admiral<br />
Codes indicate maximum numbers seen on a single visit: A=1, B=2-9, C=10-29, D=30-99, E=100+.<br />
Bookham Common TQ125165. National Trust. Strong population (C).<br />
Somersbury Wood TQ108378 Ownership not known. Strong population (D).<br />
Holmwood Common TQ180460. National Trust. Patchily dispersed, most often seen in area to north<br />
of Fourt Wents Pond. (B).<br />
Hammonds Copse TQ213445. Woodland Trust. (C).<br />
Edolphs Copse TQ2242. Woodland Trust. (B).<br />
Glovers Wood TQ228408. Woodland Trust (B).<br />
Wallis Wood TQ122388. Surrey Wildlife Trust reserve. (B).<br />
Vann Lake TQ157394. Surrey Wildlife Trust reserve. (B).<br />
Ashtead Common/Epsom Common border TQ185600 Corporation of London, SCC. (B).<br />
Ashtead Common - Occasional sightings in other areas of Common.<br />
Princes Coverts TQ160610. Crown Estate. (B).<br />
Box Hill. National Trust. Occasionally seen in wooded areas, eg Juniper Bottom (TQ180527), single<br />
sighting 1996.<br />
Mynthurst, Leigh TQ224456. Privately owned woodland. (B).<br />
Little Gaterounds, Newdigate TQ195428. Privately owned woodland. (B).<br />
Occasional single sightings from other locations:<br />
Birchy Copse, TQ188413, between Capel, Newdigate. Jordans, TQ207386 &206394, near Sussex<br />
border north of Rusper. Oakwood Hill Churchyard TQ128380, near Walliswood. Broadmoor<br />
TQ134455.