Allt y Wern

Site of Special Scientific Interest · 51.8753, -4.0649

Also within

Dyfed County

Description

Description A small oakwood which has apparently been managed as coppice-with-standards, an unusual sylvicultural practice in this part of Wales. Many of the fine mature pedunculate oaks Quercus robur are at least 200 years old. Ash Fraxinus excelsior also occurs as a standard tree whilst hazel Corylus avellana forms the coppiced layer. The species-rich shrub layer includes holly Ilex aquifolia, elder Sambucus nigra, hawthorn Crataegus monogyna, roses Rosa spp., guelder rose Viburnum opulus and blackthorn Prunus spinosa. Dog's mercury Mercurialis perennis, wood sorrel Oxalis acetosella, creeping buttercup Ranunculus repens and bramble Rubus spp. are the most abundant species in the equally species-rich ground layer.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
dog's mercury Mercurialis perennis LC herb euphorbiaceae
wood sorrel Oxalis acetosella LC herb oxalidaceae
creeping buttercup Ranunculus repens LC herb ranunculaceae
hawthorn Crataegus monogyna LC shrub rosaceae
blackthorn Prunus spinosa LC shrub rosaceae
elder Sambucus nigra LC shrub caprifoliaceae
gelder rose Viburnum opulus LC shrub caprifoliaceae
hazel Corylus avellana LC tree corylaceae
ash Fraxinus excelsior LC tree oleaceae
common oak Quercus robur LC tree fagaceae

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
Oak lutestring
Cymatophorina diluta
Endangered Quercus robur
Figure of eight
Diloba caeruleocephala
Endangered Crataegus spp., Prunus spinosa, Prunus spp.
The lappet
Gastropacha quercifolia
Endangered Crataegus monogyna, Prunus spinosa, Prunus spp.
Scarce vapourer
Orgyia recens
Endangered Corylus avellana, Crataegus spp., Prunus spinosa, Quercus spp.
Black hairstreak
Satyrium pruni
Endangered Prunus spinosa
Mouse moth
Amphipyra tragopoginis
Vulnerable Crataegus spp.
The sprawler
Asteroscopus sphinx
Vulnerable Corylus avellana, Crataegus spp., Fraxinus excelsior, Prunus spinosa, Prunus spp., Quercus spp.
Mottled umber
Erannis defoliaria
Vulnerable Corylus avellana, Crataegus spp., Prunus spinosa, Quercus spp.
The lackey
Malacosoma neustria
Vulnerable Corylus avellana, Crataegus monogyna, Prunus spinosa, Prunus spp., Quercus spp.
Pale brindled
Phigalia pilosaria
Vulnerable Corylus avellana, Crataegus monogyna, Fraxinus excelsior, Prunus spinosa, Quercus spp.
Brown hairstreak
Thecla betulae
Vulnerable Prunus spinosa
Early moth
Theria primaria
Vulnerable Crataegus monogyna, Prunus spinosa, Quercus spp.
Pale eggar
Trichiura crataegi
Vulnerable Corylus avellana, Crataegus monogyna, Prunus spinosa, Quercus spp.
Oak hook-tip
Watsonalla binaria
Vulnerable Quercus robur
Flounced chestnut
Agrochola helvola
Near Threatened Crataegus monogyna, Quercus spp.
Beaded chestnut
Agrochola lychnidis
Near Threatened Crataegus monogyna, Ranunculus spp.
Grey chi
Antitype chi
Near Threatened Crataegus monogyna
Garden tiger
Arctia caja
Near Threatened Prunus spinosa
Light crimson underwing
Catocala promissa
Near Threatened Quercus robur
Dark crimson underwing
Catocala sponsa
Near Threatened Quercus robur
Heart moth
Dicycla oo
Near Threatened Quercus robur
Large thorn
Ennomos autumnaria
Near Threatened Corylus avellana, Crataegus spp., Prunus spinosa, Prunus spp., Quercus spp.
September thorn
Ennomos erosaria
Near Threatened Quercus spp.
Dusky thorn
Ennomos fuscantaria
Near Threatened Fraxinus excelsior
Grey pug
Eupithecia subfuscata
Near Threatened Crataegus monogyna, Prunus spinosa
White-spotted pug
Eupithecia tripunctaria
Near Threatened Sambucus nigra
Double dart
Graphiphora augur
Near Threatened Crataegus spp., Prunus spinosa, Quercus spp.
Clay fan-foot
Paracolax tristalis
Near Threatened Quercus spp.
Common fan-foot
Pechipogo strigilata
Near Threatened Quercus robur
Frosted green
Polyploca ridens
Near Threatened Quercus robur

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.