Carmarthen Bay Dunes/ Twyni Bae Caerfyrddin IPA
Location: To the east of Carmarthen Bay, around the estuary of the Afon Tywi, west of the A484.
Grid Reference: SN 365 051
This Important Plant Area is home to:
• One of the UK’s most important populations of fen orchid
• An exceptional diversity of vascular plants growing in coastal dune and sand habitats.
• Some of the top 5% of dune habitats in the UK including dunes with creeping willow, very young mobile dunes, fixed dunes, shifting dunes along the shoreline and humid dune slacks.
The sparkling sea of Carmarthen Bay is fringed with several large areas of famous sand dunes. The seven mile stretch of Pendine Sands has been described as "the finest natural speedway imaginable" and was used by Malcolm Campbell to set a world land-speed record of 174.22 mph in 1927. Laugharne Sands is famous for being the last home of Dylan Thomas, while Pembrey Sands was once used as location for an episode of Most Haunted.
There’s a lot more to dunes than sun, sand and sandy sandwiches. Dunes are very complex, diverse places with lots of sand moving around and it’s this that makes them so special for plants and other wildlife, especially invertebrates such as bees, wasps and beetles.
Towards the sea, young mobile dunes with shifting sand are home to rare plants like sea stock, yellow bartsia and marsh mallow. Inland the older dunes become thickly carpeted with marram and, eventually, other grasses. These ‘fixed’ dunes can be exceptional for wildflowers, abounding with carpets of lady’s-bedstraw, common restharrow, dewberry and dune pansy, along with rarer flowers such as lesser meadow-rue and . Orchids can be plentiful, especially pyramidal orchid, and autumn lady’s-tresses and bee orchid also grow here.
The high dune ridges are divided by extensive flat areas of land that are often flooded in winter with freshwater. These damp ‘dune slacks’ are exciting places – they’re exceptionally rich in rare and uncommon plants. Creeping willow is conspicuous, especially when the catkins release their fluffy seeds. Between the small bushes orchids proliferate, especially early marsh orchid (often in a beautiful brick-red form that has been called ‘the little red welsh orchid’) and purple spikes of southern marsh orchid, along with large patches of the elegant marsh helleborine. There are also much rarer plants, like the diminutive spreading variegated horsetail, pretty dune gentian (known only from five sites in Britain) and fen orchid, found only here and at Kenfig dunes.
Other much smaller plants – mosses and liverworts - inhabit damp bare sand in and around the dune slacks. These include petalwort (a rare liverwort that looks a little like a tiny lettuce), a beautiful pinkish-coloured moss known as sea bryum and cavernous crystalwort, another liverwort that looks like a small piece of squashed broccoli.
In the past, sea buckthorn – a plant native to the east coast of England – was planted to stabilise the dunes and prevent sand moving around. This has now become highly invasive on the dunes, colonising large areas and outcompeting wildflowers. Plantlife is undertaking a programme of work to remove it and open up the sand again, providing conditions needed for many rare plants and invertebrates. For more on this work see https://www.plantlife.org.uk/uk/our-work/conservation-projects/coastal/carmarthen-bay-dunes-carmarthenshire
Image: Carmarthen Bay Dunes © Colin Cheesman/Plantlife