Coed Aber Artro

Site of Special Scientific Interest · 52.8219, -4.0747

Geology & landscape

Geological Feature: Gorge / Ravine

Landscape processes: Fluvial

Description

Description A biological site selected for its oceanic bryophyte interest. The Afon Nantcol flows into a reservoir above a sheer sided gorge strewn with rocks with such species as Harpalejeunea molleri, Grimmia hartmanii and Lophocolea fragrans growing upon the rocks and trees. Several species of fern occur including hart's tongue Asplenium scolopendrium, tunbridge filmy fern Hymenophyllum tunbrigense and wilsons filmy fern H. wilsonii. The gorge is dominated by sessile oak Quercus petraea with ash Fraxinus excelsior and odd wych elms Ulmus glabra. Beech Fagus sylvatica occurs in the gorge and is predominant above in the main wood. The ground flora consists of heather Calluna vulgaris, bilberry Vaccinium myrtillus and wavy hair grass Deschampsia flexuosa. Bryophytes carpet the ground with bluebells Hyacinthoides non-scripta, wood avens Geum urbanum and cow-wheat Melampyrum pratense. Remarks: Within the Snowdonia National Park.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
hart's-tongue fern Asplenium scolopendrium LC fern aspleniaceae
Tunrbidge filmy-fern Hymenophyllum tunbrigense VU fern hymenophyllaceae
wavy hair grass Deschampsia flexuosa Not listed in GB list grass poaceae
herb bennet Geum urbanum LC herb rosaceae
bluebell Hyacinthoides non-scripta LC herb liliaceae
common cowwheat Melampyrum pratense VU herb orobanchaceae
pointed pouncewort Harpalejeunea molleri LC liverwort jungermanniales
fragrant crestwort Lophocolea fragrans LC liverwort jungermanniales
billberry Vaccinium myrtillus LC shrub ericaceae
bell heather or ling Calluna vulgaris NT shrub dwarf ericaceae
beech Fagus sylvatica LC tree fabiaceae
ash Fraxinus excelsior LC tree oleaceae
sessile or durmast oak Quercus petraea LC tree fagaceae
wych elm Ulmus glabra LC tree ulmaceae

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

SpeciesStatusVia host-plant
Speckled footman
Coscinia cribraria
Critically Endangered Vaccinium myrtillus
Oak lutestring
Cymatophorina diluta
Endangered Quercus petraea
Shoulder-striped clover
Heliothis maritima
Endangered Calluna vulgaris
Heath fritillary
Melitaea athalia
Endangered Melampyrum pratense
Scarce vapourer
Orgyia recens
Endangered Fagus sylvatica, Quercus spp., Ulmus spp.
White-letter hairstreak
Satyrium w-album
Endangered Ulmus glabra, Ulmus spp.
The sprawler
Asteroscopus sphinx
Vulnerable Fagus sylvatica, Fraxinus excelsior, Quercus spp., Ulmus spp.
Broom moth
Ceramica pisi
Vulnerable Calluna vulgaris, Ulmus spp., Vaccinium myrtillus
Mottled umber
Erannis defoliaria
Vulnerable Fagus sylvatica, Quercus spp., Ulmus spp., Vaccinium myrtillus
Satyr pug
Eupithecia satyrata
Vulnerable Calluna vulgaris
True lover's knot
Lycophotia porphyrea
Vulnerable Calluna vulgaris
The lackey
Malacosoma neustria
Vulnerable Quercus spp., Ulmus spp.
Pale brindled
Phigalia pilosaria
Vulnerable Fraxinus excelsior, Quercus spp., Ulmus glabra
Silver studded blue
Plebejus argus
Vulnerable Calluna vulgaris
Grizzled skipper
Pyrgus malvae
Vulnerable Geum urbanum
Early moth
Theria primaria
Vulnerable Quercus spp., Vaccinium myrtillus
Pale eggar
Trichiura crataegi
Vulnerable Calluna vulgaris, Quercus spp., Vaccinium myrtillus
Oak hook-tip
Watsonalla binaria
Vulnerable Quercus petraea
Flounced chestnut
Agrochola helvola
Near Threatened Calluna vulgaris, Quercus spp., Ulmus spp., Vaccinium myrtillus
Beaded chestnut
Agrochola lychnidis
Near Threatened Vaccinium myrtillus
Dusky-lemon sallow
Cirrhia gilvago
Near Threatened Ulmus glabra
The sallow
Cirrhia icteritia
Near Threatened Ulmus glabra
Rosy marsh moth
Coenophila subrosea
Near Threatened Vaccinium myrtillus
Grey scalloped
Dyscia fagaria
Near Threatened Calluna vulgaris
Large thorn
Ennomos autumnaria
Near Threatened Quercus spp., Ulmus spp.
September thorn
Ennomos erosaria
Near Threatened Fagus sylvatica, Quercus spp.
Dusky thorn
Ennomos fuscantaria
Near Threatened Fraxinus excelsior
The Silurian
Eriopygodes imbecilla
Near Threatened Vaccinium myrtillus
Autumnal rustic
Eugnorisma glareosa
Near Threatened Calluna vulgaris, Hyacinthoides non-scripta
Double dart
Graphiphora augur
Near Threatened Quercus spp., Ulmus spp.
Weaver's wave
Idaea contiguaria
Near Threatened Calluna vulgaris
Clay fan-foot
Paracolax tristalis
Near Threatened Quercus spp.
Frosted green
Polyploca ridens
Near Threatened Quercus petraea
Scotch burnet
Zygaena exulans
Near Threatened Vaccinium myrtillus

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.