Llanelli Naturalists Newsletter - May 1995 - No 1
Ian Morgan

The ongoing Countryside Council for Wales (CCW) 'Phase 1/2 survey' of Carmarthen District and Dinefwr Borough continues, through the enthusiasm of the surveyorst, to provide very useful records particularly of butterflies associated with unimproved pastures, most especially the marsh fritillary Eurodryas aurinia and small pearl-bordered fritillary Boloria selene. Some of the sites where these species were recorded are listed below (with previously-unknown sites for the marsh fritillary marked with an asterisk (*)).

(1-Sarah Andrews (SA), Richard Howorth (RH), Morfydd Lloyd (ML), Graham Motley (GSM) and Jamie Bevan (JB)).

As usual, any unattributed records in the text are those of the author. Marsh fritillary (all record GSM & JB).

(i) nr. Bryn Coch-bach 22/572116 28.6.94 2 adults

(ii) nr. Caeau Ffos-fach 22/574124 28.6.94 7 adults.

(iii) nr. Tyllwyd-fach 22/576114 30.6.94 1 adult.

(iv) Caeau Pant-y-bryn 22/656145 5.7.94 1 adult.

[there is also an unconfirmed record from near Rhydyglyn, 22/608355 per. GSM & JB].

A visit to two sites in the Brecon Beacons National Park by Jonathan Graham and Stuart Reid also produced records at:-

(v) Brynchwith* 22/715215 15.6.94 5 adults.

(vi) Ynys Toddeb* 22/725212 27.6.94 1 adult.

Richard Pryce et a! provided a batch of marsh fritillary records from the Lower Gwendraeth valley, complementing those made in the same general area (but from different sites) by Barry Stewart in 1993. There certainly seems to be a concentration of suitable habitat for this declining butterfly in this coalfield valley. The 1994 localities are listed below:

(vii) East of Bryndias Farm* 22/438035 2.6.94 2 individuals

(viii) S. of Waun Baglam* 22/443036 2.6.94 1 individual

(ix) S. of Penllwyn Uchaf* 22/437024 16.6.94 1 individual

(x) NE of Berth Farm* 22/443044 10.6.94 1 individual

(xi) SW of Pant y gino* 22/474049 25.6.94 3 individuals

(xii) SSE of Pant y gino* 22/476048 25.6.94 3 individuals

(vii) - (x) were recorded by Richard Pryce (RDP), whilst (xi) & (xii) were recorded by RDP, Liz Flood, George Hutchinson & Janet Crowden.

This aggregation of sites, which are close to Barry Stewart's 1993 localities (where he recorded no less than 70 butterflies on the wing at one rough pasture) and other local stations for this species, could be regarded as part of a "metapopulation" as defined by Warren (1994).

 

The writer discovered another marsh fritillary site on 22nd June - at Cefn Gwili* (22/577089), where four adults were in flight with one small pearl-bordered fritillary, and a host of meadow browns Maniola jurtina and ringlets Aphantopus hyperantus. Five marsh fritillaries at Nant y Garreg* near Rhos (22/374364) on 16th June provided a new site record (RH), here Andrew Lucas (AL) also noted 10 larval webs on 12th September. A larval web was also found at Cefn-llech-clawdd (22/366394) on 5th October (RH). Near Tirlan, Llwyn-têg (22/555070), 10 or more 'marsh frits' were on the wing in warm sunshine on 27th June; and here, in October, Janet Crowden counted no less than 57 larval webs, indicating a very reasonable colony indeed. AL also counted 30 adults at Pen-ty SSSI (22/478167) on 16th June whilst John Steer noted one at Rhos Pwll y Gawnen, Trelech 22/29-29- on 8th July; both localities already known sites. Finally, Barry Stewart recorded two marsh fritillaries near Ty Croes* (22/610110) on 9th June.

A very useful survey by Melanie Bagley on behalf of CCW of known marsh fritillary sites in Dinefwr Borough in late May/June, led to the sighting of "93 individual marsh fritillaries on 15 different sites", with the highest number (45) being recorded at Caeau Ffos-fach/Broad Oak meadow (22/576120 - 22/580122) near Capel Hendre. Six previously-known sites are believed to be extinct, with losses attributed to open-casting for coal, afforestation, overgrazing or agricultural improvement of pasture. Although recognizing that there are doubtless unrecorded localities for this now-symbolic butterfly of species-rich pasture, CCW's Invertebrate Ecologist - Adrian Fowles - made the pertinent observation that this recent extinction of six "colonies" represented an approximate loss of up to 30%! Certainly, it is known that marsh fritillary colonies elsewhere in Carmarthenshire (ie in Carmarthen District and Llanelli Borough) are similarly threatened, if not directly by for example, open¬cast mining then by successional change, eg the current scrubbing-over of the Cencoed¬uchaf (22/484032) colony near Llanelli. Surviving colonies are now "islands" in a "sea" of unsuitable, lush green pastures, with no longer the linkage of appropriate pasture to aid recolonisation of temporarily unsuitable sites for the usually rather sedentary adult butterflies, though Warren (loc.cit) notes that adults can on occasions disperse as much as 15-20 kms.

Melanie Bagley's survey was followed up in September/October by Peter Hack on behalf of CCW. This confirmed that the Capel Hendre area is the only known truly viable marsh fritillary colony in Dinefwr, at least outside of the boundary of the Brecon Beacons National Park. Here, over 70 webs were discovered at Caeau Ffos Fach/Broad Oak Meadow which has to be regarded as the core of the colony, and future monitoring of these fields should be a priority. Excitingly, webs were also discovered at half a dozen other fields in the near vicinity, although these supported far less significant populations, holding a dozen or so less webs. Only at Caeau Ffos Fach was the vegetation highly suitable, with lush and abundant Succisa. On all other known sites in the Capel Hendre area succession was often occurring, with rank Molinia or Juncus threatening to swamp the Succisa, and the need for light grazing on some of these fields is urgent. Other once suitable fields here were being badly hammered by intensive pony grazing, resulting in tight unsuitable swards. This area, however, should be regarded as a priority for management, as further colonies could undoubtedly be uncovered and effort targeted at implementing correct grazing levels will result in a viable colony, the only known one in Dinefwr.

Further effort could well be rewarded if areas such as Gwynfe/Llanddeusant or the rest of the Coalfield were targeted, where habitat is more extensive and colonies are less isolated. Here, further sites could well be discovered, and if additionally new pockets of suitable habitat could be created, adjacent to existing sites, this would enhance colonies' viability. This has to be implemented if the species is to survive in one of its traditional British strongholds.

A map showing the known Carmarthenshire distribution of the marsh fritillary is shown on the next page. The rather optimistic picture it presents should be tempered by the comments given above and the realisation that this is cumulative map (mostly post-1985 records) and that some records refer to very few individuals. Indeed, the record represented by a dot in SS59 (the Llwynhendy area) can be disregarded, as it represented a single individual, presumably a wanderer from the strong colonies on the Gower commons. The map does, however, show the concentration of records on the Coalfield where the premier threat to the species is open-cast coaling. The close aggregation of records from the Lower Gwendraeth valley for example, almost precisely coincide with a proposed major open-cast site!

Small Pearl-bordered Fritillary

The Phase 2 (GSM & JB) surveyors saw small pearl-bordered fritillaries (2) at Dugoedydd (22/775416, 12th July) and three in Molinia pasture at Blaen-dyffryn (22l605442) on 13th July. This species was additionally observed in three parts of the Crychan Forest: at 22/883401 (1), 22l838404 (1) and 22l848369 (3), all on 25th June and on coastal acidic grassland at Ragwen Point 22l221073 (1) 30th June, when the year's first clouded yellows Colias croceus put in an appearance. A single "s.p.b. frit" was seen by John Ellis at Furnace Pond, Llanelli (22/503021) on 12th June and Jonathan Graham also reported three sites for this butterfly: Ynys Toddeb, (Gwynfe 22/725211 & 22/722203), 27.6.94 (c.8 butterflies): Nant Ilyndir, Cynghordy (22/822394, 7.6.94 c.4) and Cwm Sawdde, Llangadog (22/708262, a 1993 record, c.10 adults). Whilst also engaged on survey work, Sarah Andrews reported small pearl-bordered fritillaries in a field at Rhoswen (22/453330), on 7th July, and Morfydd Lloyd noted one near Pontarsais (22/438272), also in July.

A map of this species' known distribution in the county is shown below. Whilst there are clusters of records, for example in the Llanelli area (partially due to intensive recording here) and on the flanks of the eastern uplands, the species is perhaps more widely-distributed than the marsh fritillary. This is probably due to the greater survival of the rushy.

 

pastures with bog violets (one of the larval food plants), that are beloved of small pearl-bordereds, than the Succisa-rich tussocky heath-grasslands favoured by the marsh fritillary.

Agile dark green fritillaries Argynnis aglaja were noted at their usual haunts on Laugharne Burrows (22/27-07-), 12th July (AL); at Tywyn Burrows (22/36-05-, 16th July); on coastal grassland near "Top Castle", Marros (22/193075, 22nd July) and inland in Brechfa Forest (22/475283, 19th July). A few sightings of silver-washed fritillaries Argynnis paphia were reported - one just north of Pont Cych (22/272371, 23rd July) and another feeding at a flower of knapweed Centaurea nigra north of Login (22/16-24-) on 9th Sept. (both by George Hutchinson and Richard Pryce). Two more records hail from one of the species' Carmarthenshire strongholds - the Cothi Valley around Brechfa-Abergorlech, where Julian Friese (JF) saw one at Darren Fawr, Ynys Brechfa (22/537285) and another at Pont Ynyswen (22/531255), both on 24th July. John Steer also provided some west Carms. records of this fritillary: one at Llanglydwen 22/17-26-, 22nd July; "several" nearby 22/17¬25- on 4th August and one at Henllan Amgoed 22/18-20- on 21st August.

Barry Stewart and Sandra Turner also provided a very interesting record on 24th July of two small blues Cupido minimus at Wernos, Ty Croes (22/617114). The site comprises an old shaley spoil tip and the normal food plant of this butterfly in Britain - kidney vetch Anthyllis vulneraria was NOT found growing at this locality, in spite of careful searching, though it is possible that it was simply missed. Kidney vetch used to be common on old spoil tips at Great Mountain Colliery, Tumble (R.D. Pryce, pers.comm.1994). Interestingly, if this plant was absent, this is not the sole record of the small blue being found at a site without Anthyllis in Carmarthenshire: it occurred in a neutral grassland sward at Pen-ty (22/483166) in August 1988. Bird's-foot trefoil Lotus coTniculatus was frequent at the Wernos spoil tip and it is presumed that this species is being fed upon by small blue caterpillars. The thirty or so marbled whites Melanargia galathea observed at this locality also represent a noteworthy record. Often such spoil tips are regarded as environmental eye-sores and are subjected to "improvements" (usually grassing-over and with the planting of a few grey alders, white poplars or sycamores!), but these mature coalfield tips and other areas of "wasteground" are a rich wildlife resource. For example, the abundance of butterflies recorded by BS & SJT on their brief visit to the Wernos spoil tip is indicated below:

  • large white (6)
  • small white (1)
  • small skipper (c.150)
  • small blue (2)
  • red admiral (2)
  • painted lady (1)
  • small tortoiseshell (5)
  • small heath (5)
  • marbled white (c.30)
  • meadow brown (c.20)
  • gatekeeper (c.50)
  • grayling (c.70)
  • speckled wood (2)
  • ringlet (15)

 

In contrast to last year (1993), when there was only one record of a clouded yellow, summer 1994 was a moderate season for this great traveller which migrates to our shores from southern Europe. The first, as already stated, was on the coast at the very end of June but subsequently there were at least about twenty-five records, both coastal and inland, including four at Cefn Sidan beach on 23rd September (BS). The last record was made at Sandy Water Park, Llanelli (22/495006) on 11th October (Andrew Mitchell) who also reports the pale female form of the clouded yellow Colias croceus var. helice at the same site near the end of September. Migrant red admirals Vanessa atalanta were in evidence from late April to the end of June and then again from late July onwards to at least the end of October; individuals were still to be seen in early November. On 23rd September (BS) estimated about 50 red admirals flying in from over the sea at Cefn Sidan in about 4 hour's watching (along c.4m1 stretch of beach, stopping at six points to count). Painted ladies Cynthia cardui were also noted throughout the summer, again from the end of April, and five were watched feeding on sea aster Aster tripolium at Penclacwydd on 2nd September. Due to the clement weather conditions - November was reported to be the mildest since records began in 1659! (The Guardian, 30.11.94) - vanessids were around well into the early winter period. Three painted ladies were spotted by Mark Pavett on the dunes near the North Dock, Llanelli in sunny weather on 27th November and another was watched feasting at flowers of Hebe at Stradey on the same day. A late record was one seen by JF at Llandeilo on 2nd December, but the latest record of all was one seen, in sunny conditions, at Pembrey Forest on 21st December (BS). That night though, the first of several very hard frosts occurred which probably slaughtered any remaining active butterflies. The first observation of large whites Pieris brassicae was that of ten at the Penrhyngywn shingle spit (21/517973) on 30th May (BS).

Of the resident species, green hairstreaks Callophrys rubi were fluttering amongst rank gorse to the east of Gelli'r-wydd, Llwyn-tôg (22l552077) on 2nd May and with another singleton basking on a sunny, bilberry-clad laneside bank south of Llwyn-t@g (22/552077). On the same date, a male brimstone Gonepteryx rhamni was spotted at the edge of a conifer plantation behind the chapel at Llwyn-t@g (22/551082). I have seen brimstones at this latter site on previous occasions and Janet Crowden informs me of the presence of a bush of the larval foodplant, alder buckthorn Frangula alnus thereabouts, thus explaining the attraction of this locality for this butterfly. JF reported two useful records of this very local Carmarthenshire species, both well inland - above Llangadog Bridge (22/698290) and at Felindre, Llansadwrn (22/687306), both on 31st May. On 11th July, RH observed a brimstone just south-west of St David's Hospital near Carmarthen (22/388199). It was a swift-flying male which rapidly moved on. Very close to the coast, an adult brimstone was also spotted near Penybryn (21/541983) on 13th August by Barry Stewart. It is hoped that a permanent population will establish itself in the area now that alder buckthorn has been planted at the Wildfowl and Wetlands Trust Centre at Penclacwydd. Graylings Hipparchia semele were recorded at several localities, including individuals along the pathway on the landward side of Sandy Water Park (AM), where they also occur on adjacent stoney wasteground. Formerly, they were also found (together with small blues) on the nearby railway sidings below (S. of) Sandy Bridge (22/499005). Now the latter site is grassed-over and the butterflies have, expectedly, disappeared.

Commas Polygonia c-album were extremely scarce this year (after several seasons of relative plenty), and except for some records from near Furnace Pond (22/503022), (AM), there was only one other record of the holly blue Cefastrina argiolus, a singleton at WWT Penclacwydd (21/527984) on 21st August. Marbled whites were seen by severalobservers at their regular coastal stations and a noteworthy count of 30+ was made by Andrew Lucas at a known colony on neutral, unimproved pasture at "Stonefield", Llanedi (22/588085 part of the Caeau Afon Gwili SSSI, 28th July). Jonathan Graham noted one at Glynhir (22/641153) in August. This species was also noted near Wharley Point, Llansteffan, not far from Lords Park Farm (at 221337094) on 28th July, a "new site" (Richard Ellis) and one was seen on rough grassland at Gelli Aur 22/593197 on 9th and 13th Aug. (Mat Ridley).

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