OR/14/043 Site description - Brest Rhiw

Farr, G, Graham, J, and Stratford, C. 2014. Survey, characterisation and condition assessment of Palustriella dominated springs 'H7220 Petrifying springs with tufa formation (Cratoneurion)' in Wales. British Geological Survey Internal Report, OR/14/043.

Figure 18    Brest Rhiw Ordnance Survey map and GPS survey points
© Ordnance Survey.

Figure 19    Brest Rhiw Aerial photograph © UKP/Getmapping Licence No. UKP2006/01.

Figure 20    Brest Rhiw Bedrock Geology 1:50 000. © BGS © Ordnance Survey.

Table 13    Brest Rhiw water quality.

Vegetation (spring) of Brest Rhiw

Palustriella falcata dominated short vegetation between 1–3 cm height. Palustriella commutata forms locally dominant patches around two rocky spring heads which are the source of the flushed vegetation. The lower part of the site has a wide band of old and eroded tufa which has frequent cushions of Hymenostylium recurvirostrum and locally dominant patches of Jungermannia atrovirens, Preissia quadrata.

Table 14    Species list — Palustriella dominated vegetation

Agrostis stolonifera	R (<1%)
Anagallis tenella	R
Aneura pinguis	F
Bellis perennis	O
Bryum pseudotriquetrum	R
Calliergonella cuspidata	R
Campylium stellatum	F
Cardamine pratensis	O
Carex demissa	O
Carex flacca	F
Cerastium cf glomeratum	R (<1%)
Cirsium palustre	R
Climacium dendroides	R (<1%)
Cratoneuron filicinum	O
Ctenidium molluscum	R
Cynosurus cristatus	R (<1%)
Festuca ovina	R
filamentous algae (Chlorophyta)	A
Fissidens adianthoides	O
Holcus lanatus	R (<1%)
Hymenostylium recurvirostrum	F
Juncus acutiflorus	F
Juncus effusus	R (<1%)
Jungermannia atrovirens	A
Leicolea badensis	O
Nostoc sp.	O
Palustriella commutata	O
Palustriella falcata	A
Pellia endiviifolia	R
Philonotis calcarea	O
Philonotis fontana	O
Plantago lanceolata	R
Pressia quadrata	F
Prunella vulgaris	R
Ranunculus acris	R
Ranunculus repens	R (<1%)
Rhytidiadelphus squarrosus	R (<1%)
Scorpidium cossonii	F
Taraxacum sp.	R
Trifolium repens	R (<1%)
Veronica beccabunga	R

A mixture of calcareous rocks and tufa within the area of flush/spring but above the level of seepage water and supporting a small number of acrocarpous calcareous bryophyte species.

Table 15    Species list — Rocks and lumps of tufa (within area of flush/spring but above level of seepage water)

Ctenidium molluscum	R (<1%)
Ditrichum gracile	R
Schistidium sp.	R

Vegetation (adjoining spring) of Brest Rhiw

Upland acid grassland to 20 cm height (Nardus stricta, Agrostis capillaris) with extensive rush pasture dominated by Juncus effusus, Calliergonella cuspidata with scattered Juncus acutiflorus.

Table 16    Species list — Acid grassland and rush pasture

Agrostis capillaris	R
Calliergonella cuspidata	F
Juncus acutiflorus	R
Juncus effusus	A
Nardus stricta	R

Short sheep grazed calcareous grassland (to 5 cm height) dominated by Ctenidium molluscum with occasional Thymus on old mining spoil.

Table 17    Species list — Calcareous grassland
(on mining spoil)

Achillea millefolium	O
Agrostis stolonifera	R
Bellis perennis	R
Carex cf caryophyllea	R
Ctenidium molluscum	A
Cynosurus cristatus	O
Leontodon cf saxatilis	R
Plantago lanceolata	O
Thymus polytrichus	O
Trifolium repens	O

Transect vegetation and chemistry data

A transect was not undertaken at Brest Rhiw.

Condition assessment

The overall assessment is that Brest Rhiw should be classified as being in favourable ecological and hydrogeological condition.

Figure 21    Brest Rhiw photographs.