Pen-Dugwm Woods
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Geology & landscape
Geological Period: Ordovician
Description
Description These woodlands have developed on the steep sides of the narrow valley of the Nant-y- Pandy, cut in Ordovician shales. The base status of the soils in the valley as reflected by the flora appears to vary greatly. Thus parts of the north-facing oak woodlands at the western end of the site have a ground flora dominated by bilberry Vaccinium myrtillus and wavy hair-grass Deschampsia flexuosa, whilst the east-facing slopes at the southern end (with oak and some ash and elm) support a rich and varied flora, including early-purple orchid Orchis mascula and tutsan Hypericum androsaemum. The bird’s nest-orchid Neottia nidus-avis has also been recorded from the area. On the trunks of the older oak and ash trees a well developed epiphytic moss and lichen vegetation is found, including the lichen Thelotrema lepadinum. Remarks: 3 hectares of the site are owned by the North Wales Naturalists’ Trust and managed as a nature reserve, called Coed Pendugwm.
Species mentioned
Show the 6 species mentioned in the description, with red-list status| English name search for this in other sites |
Latin name search with Google |
IUCN / Red List | Type | Family |
|---|---|---|---|---|
| wavy hair grass | Deschampsia flexuosa | Not listed in GB list | grass | poaceae |
| tutsan | Hypericum androsaemum | LC | herb | hypericaceae |
| birdsnest orchid | Neottia nidus-avis | VU | herb | orchidaceae |
| early purple orchid | Orchis mascula | LC | herb | orchidaceae |
| barnacle lichen | Thelotrema lepadinum | LC | lichen | no common name |
| billberry | Vaccinium myrtillus | LC | shrub | ericaceae |
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.
| Species | Status | Via host-plant |
|---|---|---|
| Speckled footman Coscinia cribraria |
Critically Endangered | Vaccinium myrtillus |
| Broom moth Ceramica pisi |
Vulnerable | Vaccinium myrtillus |
| Mottled umber Erannis defoliaria |
Vulnerable | Vaccinium myrtillus |
| Satyr pug Eupithecia satyrata |
Vulnerable | Hypericum spp. |
| Early moth Theria primaria |
Vulnerable | Vaccinium myrtillus |
| Pale eggar Trichiura crataegi |
Vulnerable | Vaccinium myrtillus |
| Flounced chestnut Agrochola helvola |
Near Threatened | Vaccinium myrtillus |
| Beaded chestnut Agrochola lychnidis |
Near Threatened | Vaccinium myrtillus |
| Rosy marsh moth Coenophila subrosea |
Near Threatened | Vaccinium myrtillus |
| The Silurian Eriopygodes imbecilla |
Near Threatened | Vaccinium myrtillus |
| 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.