Usnea articulata in south Wales: a rare species on the move

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Usnea articulata in south Wales: a rare species on the move

Sam Bosanquet
The beard-lichen Usnea articulata is both very rare and very distinctive, making it one of the higher profile lichens on the Section 42 list. Indeed its long-pendant thalli – hanging or snagged among twigs – are noticeable even from a moving car. Its identification and historic range in Wales are detailed on
Most of the Welsh population of Usnea articulata is in Pembrokeshire, but even there it is sparsely distributed and seldom encountered. At least 10 colonies were thought to be extant in the county by 2010, including those at Stackpole NNR and Llangloffan NNR that include two or three separate sub-colonies. The BLS database also includes undated older records from SM70 and SM90. Three Glamorgan sites were known when the Glamorgan Flora was written in 1994: at Whiteford Burrows, Pennard Burrows and Kenfig Burrows. The Cardiganshire population at Hafod was last seen in the 18th century, and other colonies in SN55, SN65, SN75 and SN87 have also been lost, as has the only Radnorshire population in SO06. These inland losses are thought to result from Sulphur Dioxide pollution, although some may have been small and/or transient if the current situation is anything to judge by. Usnea articulata has been included on Section 42 of the NERC act, making it a species of “principal importance for conservation of biological diversity in Wales”, because of its rarity in Wales and the significant loss of historic sites.
Set against these losses, the discovery of more than 20 new sites for Usnea articulata in the last five years is little short of astonishing. Almost half come from the under-worked county of Carmarthenshire, with others in Pembrokeshire, Glamorgan, Cardiganshire and Breconshire. The new easternmost sites, at Gorsllwyn Onllwyn SSSI, the Taf Fechan Forest and near Ystradfellte in southern Breconshire, are very close to the industrial valleys of south Wales and are surely an indication of new colonisation rather than being relicts, whilst the population at Penllergaer is within a stone’s throw of Swansea and also seems likely to be a recent colonist. The new colonies are mostly in windy, exposed situations on hillsides or in open valleys, albeit mostly on the leeward sides of trees; a few are more sheltered. Their distribution seems relatively random, albeit with clusters in Brechfa Forest (where SB lives) and on the Carmel ridge. The discovery of further populations seems almost inevitable, although it is not really practical to actively search for U. articulata because it is so localised and so unpredictable: it is better just to remain ever-vigilant and to keep scanning tree-tops.

Details of the new populations are:

Glamorgan (v.-c. 41): SS 50358 87551, Oxwich Middle Pond, 2 tufts on Alder, Sam Bosanquet 2011.

Glamorgan (v.-c. 41): SS 628 983, Penllergaer Valley Woods, Kevin Davies 2009/2010.

Breconshire (v.-c. 42): SN 85410 10973, Gors Llwyn Onllwyn SSSI, 10cm tuft on Willow (photo below left); SN 85474 11025, Gors Llwyn Onllwyn SSSI, 20cm tuft on Willow (photo below right); SN 85504 11046, Gors Llwyn Onllwyn SSSI, 15cm tuft on Willow, Sam Bosanquet 6th June 2012.

Breconshire (v.-c. 42): SN 93 12 to SN 94 12, Gwaun Hepstre (near Ystradfellte), Jon Hudson & Nick Hudson 21st October 2012 and Sam Bosanquet & Graham Motley 1st November 2012.

SN 9342 1256

20cm tuft snagged in Hawthorn below Larch


SN 9367 1279

15x15cm tuft on Larch on NW edge of plantation (photo below left)


SN 9392 1243

30cm tuft snagged 5m up Larch on edge of plantation


SN 9401 1239

100cm strip 30 cm long on lower branch of Larch on SE edge of plantation (photos below right)


SN 9410 1211

20cm tuft snagged on Larch


SN 9411 1210

10cm tuft on Larch


Breconshire (v.-c. 42): SO 047 159, Pont y Llwyn, Taf Fechan Forest (just north of Pentwyn Reservoir), 20cm tuft on lowest branch of Larch near edge of mixed broadleaved/conifer plantation, Graham Motley, 6th November 2012.

Carmarthenshire (v.-c. 44): SN 5043 2731, Mynydd Bryn-bugail, 30cm tuft on roadside Hawthorn, Sam Bosanquet 13th November 2012.

Carmarthenshire (v.-c. 44): SN 5109 3155, Brechfa Forest above Cnwc-y-llwyn, 25cm tuft in roadside Oak, Sam Bosanquet 2010.

Carmarthenshire (v.-c. 44): SN 5181 3398, Pant-y-Rhyg, Brechfa, 1 tuft in roadside Rowan, Sam Bosanquet February 2012.

Carmarthenshire (v.-c. 44): SN 5262 2907, above Gilfach-y-rhiw, Horeb, 5 tufts on roadside Hawthorn, Sam Bosanquet 5th November 2012 (visible on Google Street View!).

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Carmarthenshire (v.-c. 44): SN 537 346, Esgair-ffynwent, Gwernogle, 20+ tufts in windy Hawthorn bushes, Michelle Hanna det. Sam Bosanquet 11th February 2012 (photo below).

Carmarthenshire (v.-c. 44): SN 58 16, Pwll Edrychiad, Carmel, on 6 Hawthorn bushes, Jamie Bevan 2006 & 2012 (photos below).

Location 1

SN 5844 1617

Numerous large tufts on old Hawthorn (photo below left)

Location 2

SN 5837 1621

2 large tufts on old Hawthorn

Location 3

SN 5839 1618

ca. 20-30 cm tuft on old Hawthorn

Location 4

SN 5837 1617

ca. 20-30 cm tuft on old Hawthorn

Location 5

SN 5833 1616

ca. 20-30 cm tuft on old Hawthorn

Location 6

SN 5834 1611

ca. 20-30 cm tuft on old Hawthorn (photo below right)

Carmarthenshire (v.-c. 44): SN 606 166, Pant-y-llyn, 1 tuft on Hornbeam, Nigel Stringer.

Carmarthenshire (v.-c. 44): SN 639 151, Glynhir Mansion walled garden, 2 tufts in Apple trees, BLS October 2010.

Pembrokeshire (v.-c. 45): SM 8924 1493, Rosehill, abundant in short Willow scrub, Jon Hudson 7th May 2011.

Pembrokeshire (v.-c. 45): SM 9602 2445, Treffgarne Gorge, abundant on hybrid Black Poplar, Jon Hudson 20th December 2011.

Pembrokeshire (v.-c. 45): SM 97 34 (details below), Esgyrn & Llanwern, large & small tufts on at least 15 trees of 6 species, Sam Bosanquet & Jon Hudson 23rd October 2012.

SM 9708 3494

2 large tufts in Oak canopy (photo, viewed from track up to Esgyrn Farm)

SM 9709 3495

5 tufts in Oak canopy, 1 in Rowan & 1 in Hawthorn

SM 9731 3495

1 scrap on Oak branch

SM 9732 3497

1 large tuft on Hawthorn on field edge

SM 9736 3493

2 large patches on Oak

SM 9740 3495

1 tuft on Willow on field edge

SM 9744 3489

1 small tuft on Oak

SM 9753 3486

2 tufts in Oak canopy

SM 9755 3488

1 very large tuft in Sycamore canopy (photo, viewed from Llanwern parking area)

SM 9756 3486

1 tuft in Ash canopy

SM 9758 3492

2 small tufts in Sycamore

SM 9763 3483

1 large tuft on Oak & 1 small tuft on Willow

Pembrokeshire (v.-c. 45): SN 05225 30152, abundant on one Larch, Ty Rhyg, Huw Denman det. Theresa Greenaway, August 2012.

Pembrokeshire (v.-c. 45): SN 0593 1464, Blackpool Mill, in small quantity, Jon Hudson May 2012.

Pembrokeshire (v.-c. 45): SN 085 338, Tafarn-y-bwlch, in windy Hawthorn bush, Jon Hudson 2010.

Cardiganshire (v.-c. 46): SN 4574 5158, Rhos Garn Whilgarn, “a small tangle wrapped round a branch ca. 15ft up a Larch and three diminutive strands to c. 4cm at eye-level on the same tree”, Steve Chambers 2012.

Cardiganshire (v.-c. 46): SN 5467 5981, Maes-y-crugiau/Trychrug south, 10 tufts in windy Hawthorn bushes, Sam Bosanquet 17th November 2011; Trychrug SN545600, 1 tuft in Willow, Steve Chambers 2011.

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