OR/14/043 Conclusions

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.

Palustiella dominated vegetation (based on 27 samples) has loosely been divided into 2 main groups and 4 subgroups. The two main groups (1 and 2) are shown to differ generally in respect to dominanace of individual Palustriella species, attitude, site ‘openness’ and number of flowering plant species. The two groups also correlate well to NVC M38 and M37 communities respectively.

Palustriella dominated spring vegetation is an interesting habitat due to its strong topographical and hydrogeological components, is generally not species rich (6–52 species) and has very few species of conservation concern although Blysmus compressus (not recorded during the present survey) is an associated species of conservation concern listed as vulnerable in the Red Data Book (Cheffings & Farrell, 2005). Microtopography is an important factor influencing the character and structure of Palustriella dominated springs.

The presence of tufa is not considered to be a contolling factor in the occurance of Palustriella dominated springs and NVC M37/M38 communities. It is noted that this could be problematic as it does not fit with the European Commission definition of the Annex I habitat H7220 Petrifying springs with tufa formation (Cratoneurion) as being ‘springs with active formation of tufa’.

The sites were divided into Group 1 and Group 2 and the key defining features of each group are summarized in Table 115.

All but one of the sites surveyed were considered to be in favourable ecological condition and all of the sites were considered to be in good hydrological condition, the results are presented in Table 116.

Table 115    Summary of key ecohydrolgoical divisions between Group 1 and Group 2

	Group 1	Group 2
Key species	Dominantly Palustriella falcata	Only Palustriella commutata
NVC Community	M 38	M 37
Elevation	Upland	Lo wland
Elevation range	275–690 ma OD	5–402 ma OD
Average Elevation	426 ma OD	85 ma OD
Vegetation: Total species Flowering plants* Small Carex species	Often with Festuca ovina 21–52 11–27 2–3	Often with Festuca rubra 5–20 1–10 0–2
Flow	Smaller flows (<0.1–0.5 l/s)	‘Larger’ flows (<0.1–1 l/s)
Occurrence of tufa	Less tufa — some sites with no tufa	More tufa — often deposited in significant quantities under natural conditions
Water chemistry	Less base rich (as bicarbonate)?	More base rich (as bicarbonate)?
Water Quality	Low nutrient levels	higher nutrient levels
Openness of site	Open	Typically not open (incl. woodland, cliffs and gorges)
Land use	Upland/common land	Lowland agricultural
Grazing pressure	Significant	Low or none (incl. Many vertical sites)
Ecological Pressures	2 sites (Nant Peris 1 and 2) with invasive alien Epilobium brunescens	No pressures identified
Hydrological Pressures	No pressures identified	No pressures identified
* flowering plants (including club mosses, horsetails and true ferns)

Table 116    Summary of ecological and hydrological status

Site	Tufa forming?	Qualify as habitat H7220	Ecological condition	Hydrological Status	Overall condition
Foel Fawr Site 1	Yes	Yes	Favourable	Good	Favourable
Foel Fawr Site 2	Yes	Yes	Favourable	Good	Favourable
Foel Fawr: Foel Garnach	v.small area	Yes	Favourable	Good	Favourable
Foel Fawr: Brest Rhiw	Yes	Yes	Favourable	Good	Favourable
Pont Clydach 1	No	Yes	Favourable	Good	Favourable
Pont Clydach 2	No	Yes	Favourable	Good	Favourable
Pont Clydach 3	No	Yes	Favourable	Good	Favourable
Blaen Onneu	Yes	Yes	Favourable	Good	Favourable
Llyn y Fan Fach 1	v.small on one plant	Yes	Favourable	Good	Favourable
Llyn y Fan Fach 2		Yes	Favourable	Good	Favourable
Cwm Clydach	Yes	Yes	Favourable	Good	Favourable
Waun Ddu/Craig y Cilau	No	Yes	Favourable	Good	Favorable
Tarren y Esgob	Yes	Yes	Favourable	Good	Favourable
Hen Allt Common	Yes	Yes	Favourable	Good	Favourable
Cors Erdderiniog 7A Pipe	Yes	NO — minimal size of Palustriella veg	Favourable	Good	Favourable
Cors Erdderiniog	Yes	Yes	Favourable	Good	Favourable
Cors Erdderiniog	Yes	Yes	Favourable	Good	Favourable
Cors Erdderiniog F	Yes	NO — minimal size of Palustriella veg	Favourable	Good	Favourable
Fedw Fawr Beach 1	Yes	Yes	Favourable	Good	Favourable
Fedw Fawr Beach 2	Yes	Yes	Favourable	Good	Favourable
Fedw Fawr Beach 3	Yes	Yes	Favourable	Good	Favourable
Ddol Uchaf	Yes	NO — minimal size of Palustriella veg	Favourable	Good	Favourable
McWalters Dingle 1	Yes	Yes	Favourable	Good	Favourable
McWalters Dingle 2	Yes	NO — minimal size of Palustriella veg	Favourable	Good	Favourable
Nant Peris 1 and 2	No	Yes	Unfavourable	Good	Unfavourable
Nant Peris 3	No	Yes	Favourable	Good	Favourable