Protected areas

A number of protected areas are in, or close to Senni Valley. They include one 'Special Area of Conservation' (SAC), five 'Sites of Special Scientific Interest' (SSSI) and one 'National Nature Reserve'. Some of these are on private land and may only be visited with permission from the landowner.

Special Area of Conservation (SAC)

The Usk River and its tributaries that include the Senni River are a designated 'Special Area of Conservation', notified to the Government by the Joint Nature Conservation Committee (JNCC). Its importance is partly  because "The River Usk is an important site for otters Lutra lutra in Wales. They are believed to be using most parts of the main river, from Newport upstream, and in recent years signs of otters have increased. In 1991 an expansion upstream of known otter ranges was recorded on several tributaries, including the Honddu, Senni and Crai. The upper Usk may have acted as a ‘refuge’ during the decline of the 1950s, and had subsequently acted as a ‘source’ population for recolonisation of south-east Wales.

Sites of Special Scientific Interest (SSSI)

Natural Resources Wales is responsible for the five Sites of Special Scientific Interest (SSSI) in the Senni Valley and neighbouring areas.

1 Coed Mawr - Blaen-Car SSSI, which is on private land and a permit is required to visit it.
National Grid reference: SN930285. Total Area: 13.2 ha
The site comprises a fine example of damp semi-natural woodland with adjacent areas of unimproved hay meadow and wet pasture, lying alongside Nant Car, south-east of Sennybridge.
Coed Mawr contains two distinct types of woodland. The wetter ground supports a canopy of alder Alnus glutinosa with much grey willow Salix cinerea and hazel Corylus avellana. The ground flora is characterised by an abundance of opposite-leaved golden-saxifrage Chrysosplenium oppositifolium, meadowsweet Filipendula ulmaria, creeping soft-grass Holcusm mollis and creeping buttercup Ranunculus repens, with marsh-marigold Caltha palustris and yellow iris Iris Pseudacorus being locally prominent. The drier ground supports a canopy of sessile oak Quercus petraea, including many large mature to over-mature specimens supporting a rich lichen flora. The understorey here consists of hazel coppice and holly Ilex aquifolium. The ground flora is fairly grassy, but herbs such as bluebell Hyacinthoides non-scripta, wood-sorrel Oxalis acetosella and greater stitchwort Stellaria holostea are abundant throughout. Wood anemone Anemone nemorosa and pignut Conopodium majus are locally frequent. A clearing within the wood is largely dominated by purple moor-grass Molinia caerulea, but also contains banks of drier grassland dominated by common bent Agrostis capillaris and fescues Festuca spp., with a variety of herbs, including common knapweed Centaurea nigra, bitter-vetch Lathyrus montanus, great burnet Sanguisorba officinalis, saw-wort Serratula tinctoria, betony Stachys officinalis and devil's-bit scabious Succisa pratensis. An area of hay meadow lies immediately to the east of the wood. This mostly well-drained area is dominated by a mixture of grasses which includes common bent, fescues and sweet vernal-grass Anthoxanthum odoratum. Frequent associates are common knapweed, common bird's-foot-trefoil Lotus corniculatus, tormentil Potentilla erecta, great burnet and devil's-bit scabious. An old hedge-line runs across the centre of the area. This is bordered by a strip of damp grassland dominated by sharp-flowered rush Juncus acutiflorus, with abundant purple moor-grass, meadowsweet and tufted hair-grass Deschampsia cespitosa, and also frequent sneezewort Achillea ptarmica and marsh willowherb Epilobium palustre. Meadow thistle Cirsium dissectum occurs locally in this area. The remainder of the site comprises an area of damp species-rich pasture to the east of Blaen-car farm. The wetter ground supports a community dominated by meadowsweet with frequent Yorkshire-fog Holcus lanatus, wild angelica Angelica sylvestris, marsh thistle Cirsium palustre, wood horsetail Equisetum sylvaticum, sharp-flowered rush, creeping buttercup and common valerian Valeriana officinalis. Elsewhere purple moor-grass becomes dominant, although the species listed above remain prominent, along with creeping bent Agrostis stolonifera, common marsh-bedstraw Galium palustre, compact rush Juncus conglomeratus and common sorrel Rumex acetosa. Other associates include marsh-marigold, greater bird's-foot-trefoil Lotus uliginosus, ragged-robin Lychnis flos-cuculi and marsh valerian Valerian dioica. Small areas of drier grassland occur within this field. These support a wide variety of species, including common bent, fescues, sweet vernal-grass, Yorkshire-fog, common knapweed, dyer's greenweed Genista tinctoria, creeping willow Salix repens, great burnet, saw-wort, betony, devil's-bit scabious and wood bitter-vetch Vicia orobus.This large area of herb-rich grassland lying in close proximity to a fine woodland presents a rare juxtaposition of habitats known elsewhere to support notable invertebrate populations. These still await study at this site.

2 Penllwyn-yr-Hendy SSSI, which is on private land and a permit is required to visit it.
National grid reference: SN 929227. Site area: 2.7 hectares
At least seven different types of grassland and fen communities are present in this small site, grading into each other and into scrub woodland, to produce one of the most diverse grassland sites in Brecknock.
The site is divided into two by a fence. The southern field supports extensive areas of the now scarce small-sedge mire, dominated by carnation sedge Carex panicea, tawny sedge C. hostiana and purple moor-grass Molinia caerulea. Characteristic associates include dioecious sedge Carex dioica, star sedge C. echinata, round-leaved sundew Drosera rotundifolia, bulbous rush Juncus bulbosus, common butterwort Pinguicula vulgaris and marsh arrowgrass Triglochin palustris. A variant of this community dominated by fewflowered spike-rush Eleocharis quinqueflora and common cottongrass Eriophorum angustifolium occupies some of the wetter hollows, whilst other channels and soakaways support species such as bogbean Menyanthes trifoliata, bog pondweed Potamogeton polygonifolius, water horsetail Equisetum fluviatile and marsh lousewort Pedicularis palustris. Drier hummocks support a community dominated by purple moor-grass, carnation sedge, sheep’s fescue Festuca ovina and bents Agrostis spp., with frequent heather Calluna vulgaris, deergrass Trichophorum cespitosum, petty whin Genista anglica and tormentil Potentilla erecta. Around the fringes of the small-sedge mire there are stands of taller vegetation dominated by sharp-flowered rush Juncus acutiflorus and purple moor-grass. Associated species here include common marsh-bedstraw Galium palustre, greater bird's-foot-trefoil Lotus uliginosus, wild angelica Angelica sylvestris, marsh thistle Cirsium palustre, common sedge Carex nigra, marsh violet Viola palustris and marsh speedwell Veronica scutellata. These stands grade into a community dominated by soft rush Juncus effusus along the eastern edge of the field. The western side of the field is much wetter and comprises patches of alder Alnus glutinosa interspersed with tall-fen vegetation. Lesser pond-sedge Carex acutiformis, sharpflowered rush and meadowsweet Filipendula ulmaria are prominent here with a wide range of associates, including water horsetail, bogbean, common sedge, fen bedstraw Galium uliginosum, marsh-marigold Caltha palustris, water mint Mentha aquatica, common valerian Valeriana officinalis, creeping-Jenny Lysimachia nummularia and marsh cinquefoil Potentilla palustris.

3 Cae Gwernllertai, which is on private land and a permit is required to visit it.
National Grid reference: SN943244. Total Area: 1.6 ha
The site comprises a small area of unimproved damp pasture in Cwm Brynych, south of Sennybridge. The field supports an unusual variety of plant species and communities for its size.
The site is bounded to the north and west by a small brook with associated areas of alder Alnus glutinosa woodland and soft rush Juncus effusus dominated marsh. Elsewhere the driest ground supports a sward dominated by mat-grass Nardus stricta, purple moor-grass Molinia caerulea and sheep's fescue Festuca ovina, with abundant tormentil Potentilla erecta and carnation sedge Carex panicea. Heath-grass Danthonia decumbens occurs throughout, with heather Calluna vulgaris and deergrass Trichophorum cespitosum locally prominent. Heath spotted-orchid Dactylorhiza maculata, petty whin Genista anglica and sawwort Serratula tinctoria occur within this community. There are unusually extensive areas of flush dominated by small sedges Carex spp. and purple moor-grass, with accompanying species such as bog pimpernel Anagallis Tenella, quaking-grass Briza media, meadow thistle Cirsium dissectum, bulbous rush Juncus bulbosus and devil's-bit scabious Succisa pratensis. An area of marshy ground in the centre of the field is dominated by sharp-flowered rush Juncus acutiflorus; associates here include water horsetail Equisetum fluviatile, common marsh-bedstraw Galium palustre, ragged-robin Lychnis flos-cuculi, lesser spearwort Ranunculus flammula, marsh valerian Valeriana dioica and eight species of sedge.

4 Illtyd Pools, on Mynydd Illtyd, Common Land. Open access, but keep to marked paths.
National grid reference: SN 965256 and SN 959264. Site area: 93 hectares
This collection of pools and peat-filled hollows on the summit ridge of Mynydd Illtyd is of great botanical and entomological interest. Some of the pools, fed by lime-rich water, support a number of rare calcicolous plant species, including the rare fen-sedge Cladium mariscus and slender sedge Carex lasiocarpa, here at their only known Brecknock locality. Other pools are more acidic, with floating mats of vegetation at their edges. Peat has formed in some hollows producing hummock and hollow mires with well developed hummocks of bog mosses Sphagnum spp. and lichens Cladonia impexa predominating. A number of uncommon aquatic insects have been recorded in the pools and streams, whilst the hummocks of the mires support an unusual spider fauna. In autumn and winter the site is of ornithological interest, being frequented by waders and other waterfowl.
49 hectares are managed as a nature reserve by the Brecknock Naturalists’ Trust by agreement with the commoners and the Lord of the Manor. The reserve is known as The Traeth, Mynydd Illtyd.

5 Heol Senni Quarry SSSI, which is on private land and is hazardous from falling rock. A permit should be obtained from the Warden in the CCW Area Office phone 01597-824661, to visit it.
National grid reference: SN 914222. Site area: 3.4 hectares
See the extended description on this web.

National Nature Reserve

Craig Cerrig Gleisiad & Fan Frynych, open access but keep to marked paths. There are dangerous cliff faces.

The drive along the A470 between Brecon and Merthyr Tydfil gives you a fleeting glimpse of the high cliffs of Craig Cerrig Gleisiad which tower darkly on the slopes above the road. The reserve extends for a considerable distance over this upland, taking in moors and bogs, the crags of Craig Cwm Du and the summit of Fan Frynych.
The rusty coloured rocks of the reserve are Old Red Sandstone: these were formed following the mountain building episode in North Wales, as silty sand was deposited in shallow seas over a period of 50 million years.
The present day landscape, with its steep rocky backwall and slopes of loose scree rising dramatically above the bumpy land surface at the bottom of the cwm, was shaped by successive Ice Ages and by huge landslips. In Cwm Du you can also see remains of old terraces created by a river of meltwater, as it flowed in different positions, constantly adjusting to changes in the landscape after the last Ice Age.
The rocks are not only a fascinating geological feature, but also an important wildlife habitat. Old Red Sandstone can sometimes contain plenty of lime, as is the case at Craig Cerrig Gleisiad. Here, on the rocky ledges and in the crevices, beyond the reach of the grazing sheep, a rich collection of alpine plants can be found – such as roseroot, purple saxifrage, mossy saxifrage, globeflower and serrated wintergreen. Many of these are at, or near their southernmost limit of distribution in Britain on this reserve.
More than 500 plants have been recorded on the reserve. The variety of habitats, including bog, moor, grassland, pools and streams, woods and rocks makes this reserve a rich site for wildlife.
On the moorland which covers most of the reserve, patches of heather and bilberry are mixed with extensive areas of typical upland grassland, where flowers such as tormentil, heath bedstraw, milkwort and eyebright provide splashes of colour in summer. Along streams and in places where water trickles through the soil, the variety of plants can be much richer. A few patches of peat bog support a wonderful mix of different sedges, rushes and bog mosses along with flowers such as cross leaved heath, cotton grass, bog asphodel and sundew. Rowan, silver birch and hawthorn are scattered across the slopes and additional trees have been planted in places to add to the variety of habitats on the reserve.
You may well see some of the 16 species of butterfly on a visit during the summer, including some of the more uncommon species such as green hairstreak, whose caterpillars feed on bilberry in upland areas.
A spring or early summer visit will certainly provide sightings of some of the typical upland birds found on the reserve. 80 species of birds have been recorded here : wheatear, meadow pipit and skylark are a common sight on the grassy, sheep grazed slopes whilst dippers and grey wagtails are frequently seen darting back and forth along the boulder strewn streams. On the steeper rocky slopes, keep an eye open for the uncommon ring ouzel and for ravens and peregrine falcons which haunt the highest crags. Merlins are fond of the habitat around the edges of the reserve where woodland fringes open moorland and the common sandpiper sometimes visits the open water pools of the reserve.

Page updated 19/12/2018