Coedydd Tregyb / Tregyb Woodlands
Habitats
Description
Description Three woods, Cae'r Coed, Big Grove and Warren Tregyb make up this site and form, with surrounding contiguous areas of woodland, one of the largest blocks of deciduous woodland in south-east Dyfed. From an examination of old maps it appears that areas on the western edge of Big Grove and at the south-eastern end of Warren Tregyb were formerly fields. They are now botanically indistinguishable from the surrounding woodland which has developed on undulating ground overlaid with clay. Drier ridges alternate with flushes and damp river valleys supporting ash/oak Quercus petraea and Quercus robur woodland and alder/willow carr respectively. All three woods have a well developed and species-rich shrub and ground layer, being largely free of grazing animals. At least 100 species of flowering plants have been recorded in the ground layer. Since much of the woodland appears to have been clear felled in recent times epiphyte communities of the tree trunks are not well developed. The few old trees which do remain, especially along old boundary banks, are however of some interest and provide a refuge for many species rare or absent elsewhere in the woods. All the larger woodland mammals are present and fallow deer occurred until recently. Remarks: Within the Brecon Beacons National Park.
Species mentioned
Show the 2 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 |
|---|---|---|---|---|
| sessile or durmast oak | Quercus petraea | LC | tree | fagaceae |
| 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.
| Species | Status | Via host-plant |
|---|---|---|
| Oak lutestring Cymatophorina diluta |
Endangered | Quercus petraea, Quercus robur |
| Scarce vapourer Orgyia recens |
Endangered | Quercus spp. |
| The sprawler Asteroscopus sphinx |
Vulnerable | Quercus spp. |
| Mottled umber Erannis defoliaria |
Vulnerable | Quercus spp. |
| The lackey Malacosoma neustria |
Vulnerable | Quercus spp. |
| Pale brindled Phigalia pilosaria |
Vulnerable | Quercus spp. |
| Early moth Theria primaria |
Vulnerable | Quercus spp. |
| Pale eggar Trichiura crataegi |
Vulnerable | Quercus spp. |
| Oak hook-tip Watsonalla binaria |
Vulnerable | Quercus petraea, Quercus robur |
| Flounced chestnut Agrochola helvola |
Near Threatened | Quercus spp. |
| 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 | Quercus spp. |
| September thorn Ennomos erosaria |
Near Threatened | Quercus spp. |
| Double dart Graphiphora augur |
Near Threatened | 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 petraea, 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.
Plant communities
A14 — Fast flowing river and stream
Myriophyllum alterniflorum community
Show 15 indicator speciesIsolepis fluitans, Juncus bulbosus, Fontinalis antipyretica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Lemna minor, Callitriche stagnalis, Littorella uniflora, Potamogeton filiformis, Potamogeton gramineus, Potamogeton natans, Ranunculus peltatus, Chara spp., Nitella hyalina
A17 — Chalk river and stream, Fast flowing river and stream
Ranunculus penicillatus ssp. pseudofluitans community
Show 11 indicator speciesBerula erecta, Nasturtium officinale, Elodea canadensis, Lemna minor, Callitriche stagnalis, Veronica beccabunga, Polygonum amphibium, Polygonum hydropiper, Potamogeton crispus, Potamogeton pectinatus, Ranunculus penicillatus ssp. pseudofluitans
A18 — Fast flowing river and stream
Ranunculus fluitans community
Show 12 indicator speciesFontinalis antipyretica, Fontinalis squamosa var. curnowii, Myriophyllum alterniflorum, Myriophyllum spicatum, Elodea canadensis, Mentha aquatica, Lemna gibba, Lemna minor, Potamogeton perfoliatus, Ranunculus fluitans, Glyceria fluitans, Phalaris arundinacea
A9 — Fast flowing river and stream, Marginal and inundation, Pond ditch and canal, Sluggish river and stream
Potamogeton natans community
Show 20 indicator speciesSchoenoplectus lacustris, Juncus bulbosus, Sparganium angustifolium, Sparganium erectum, Sparganium minimum, Alisma plantago-aquatica, Lobelia dortmanna, Equisetum fluviatile, Myriophyllum alterniflorum, Elodea canadensis, Lemna minor, Lemna trisulca, Nymphaea alba, Callitriche platycarpa, Callitriche stagnalis, Littorella uniflora, Potamogeton natans, Ranunculus trichophyllus, Glyceria fluitans, Chara subspinosa