The valleys of south Wales have been formed and moulded by the rigours and forces of successive Ice Ages. The geomorphological and geological heritage of Rhondda Cynon Taff is immensely rich and varied and is inextricably linked with the County Borough’s superb biodiversity. The crags and scree slopes of Rhondda Cynon Taff are glacial features and habitats of considerable biodiversity value at the southern extreme of their UK distribution. 

 

The Rhondda and the Cynon Valleys boast a fantastic series of glacial cwms, at the very southern end of range in the British Isles. To see equivalent features further south one would have to visit the French Pyrenees or Alps. Crags are the back-faces of the glacial cwms, where ice accumulated and the glaciers began their grinding journeys, gouging out the valleys. Crags with north-facing aspects are refuge for plant species and communities which were common immediately after the last Ice Age, but now are now found much further north than RCT.

 

For countless generations, the forebears of these plants have been stranded on the same cold sunless ledges, species that include roseroot, oak fern, parsley fern and fir clubmoss. Crags also offer safe nesting sites for birds of prey (notably peregrine) and ravens. Below the crags, where the ground starts to shallow out into the glacial cwms or bowl, there is a zone of broken ‘freeze-thawed' rock or scree slopes. These utterly characteristic glacial features may appear to be sterile habitats of little note, however they are special places of a unique biodiversity value. Distinctive vegetation communities; including club-mosses, ferns, heathland and their specialist invertebrates are often associated with scree sites. Associated with the glacial landscapes are steep streams in gorges and spectacular waterfalls e.g. Blaencwm.  Here, temperate rainforest woodland thrives in the humidity and trunks, branches, twigs and wet rock faces are richly cloaked in ferns, lichens, mosses, and liverworts.   

 

Unfortunately, because of a lack of recognition, the glacial bowls of some of our best cwms  have been damaged. For example, parts of the extensive formations below Graig Fawr (Cwmparc) were used for colliery spoil disposal and, despite its status as a Site of Special Scientific Interest, the bowl at Cwm Saerbren has been planted with conifers. As a result much of the glacial material deposited by the glacier, the moraines, has been damaged and a fundamental part of the geomorphological story and biodiversity of individual sites has been compromised. However, there is potential to reveal more of the geomorphology and recover some of the lost habitat potential through sympathetic management and conifer removal.

 

RCT is extremely fortunate to support such beautiful natural landforms and it is, surely, finally their time to be recognised as outstanding natural assets. If, through the LNP, this recognition and restoration can be promoted, then Wales third glacial landscape can perhaps be acknowledged and nurtured along with famous two: Snowdonia and the Brecon Beacons.  

Quarries, both pennant sandstone and limestone are another of the industrial landscape features of RCT. The grand Edwardian houses and iconic Victorian terraced streets of RCT were built from stone won from Valleyside quarries, while post second world war sandstone and limestone extraction for roads and industry has driven the expansion of a few super quarries. In all cases, habitat was initially lost but there is some recompense in the creation of new ‘crags and rock faces’ onto which peregrines and raven nest and fern communities establish. There is also potential in the quarry bowls, ledges and surrounds to give space for species rich limestone and acid grasslands to develop if ecological focused aftercare can be argued for and secured in quarry restoration schemes.  

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