Habitats of the Cambrians

Cynefinoedd o’r Mynyddoedd Cambria

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Atlantic Woodland – often dominated by Sessile Oak and occasional Birch, Hazel, Rowan, and with Ash, Alder, Elm and Small-leaved Lime in some places. The ground flora has an abundance of bryophytes (mosses and liverworts) and older trees can support a rich epiphytic lichen flora. The Celtic Rainforest Wales Project is working on two sites in the Cambrians aiming to rid them of invasive species and improve habitat.

Upland Heathland (Dwarf shrub heath) – includes Heathers, Bilberry, Cowberry and Crowberry. The highest, most exposed ridge of the Pumlumon SSSI has extensive carpets of Alpine and Stag’s-horn Clubmoss as well as two rare montane species, Stiff Sedge and Dwarf Willow. These are however both very localised.

stag's horn clubmoss

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Blanket Bog – the Elenydd SAC comprises the largest tract of blanket mire south of the Berwyns and Mignient in Snowdonia with the remote Claerwen National Nature Reserve at the core. Extensive stands of Cross-leaved heath, Bog moss (Sphagnum) species, and the locally abundant Bog Rosemary are found as well as areas of mire in which Heather and Hare’s-tail Cotton-grass are dominant.

Not all blanket bog in the Cambrians is in good condition, displaying signs of modification with impoverished vegetation dominated by Purple Moor-grass (Molinia caerulea) with reduced amounts of dwarf shrubs and Sphagnum species. As part of the National Peatland Action Programme, NRW been carrying out peatland restoration in the Claerwen NNR and Tywi Forest areas.

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Upland lakes – a series of clear water, acidic, nutrient-poor (oligotrophic) lakes stretch from Glaslyn in the north, through the Elenydd lakes to Llyn Gynon.

The remote Elenydd lakes are amongst the best oligotrophic upland lakes in Wales and have been relatively untouched by abstraction and water-level modification. Their populations of Floating Water-plantain are an apparently ancient refuge site secure from the intensification that has afflicted lowland populations. Associated species includes Quillwort, Water Lobelia, and Floating Bur-reed.

Awlwort, the only aquatic species in the Cabbage family, occurs at its southernmost site in the UK at Teifi Pools. This species is endangered and on Wales Red List.  Small, edge of range populations are particularly important as they are often genetically distinct.

Rivers and streams – within the Cambrian Mountains this includes the upper reaches of two Special Areas of Conservation:

  • the Upper Wye, together with the Irfon sub-catchment (tributaries of the Wye rising north of Llanwrtyd Wells)
  • the uppermost section of the River Teifi above Tregaron Bog.

SAC-designated Key Species include: Atlantic Salmon; Otter; Bullhead; Brook and River Lamprey. Although the Towy rises in the Cambrians, SAC designation starts at Llandovery.

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rhandirmwyn

Lowland Meadows – an increasingly rare and fragmented habitat of herb-rich meadows cut for hay or silage.   

The Elan Valley supports some of the richest examples of neutral grassland in Wales. A suite of twelve SSSIs particularly noted for their upland fringe hay meadows can be found here. These flowery meadows include Harebell, Fairy Flax, Eyebright, Yellow Rattle, Betony, Devil’s-bit Scabious, Greater Butterfly Orchid and Wood Bitter-vetch (a Priority Species in Wales).

Calaminarian grasslands – these are centred on Cwmystwyth mines in the Elenydd SAC and noted for their heavy-metal tolerant (metallophyte) lichens and bryophytes. Both the habitat and species assemblage are included in Wales list of Priority Habitats and Species (Environment Wales Act 2016).

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