Long-leaved thread moss is one of the easiest of the Bryum group of mosses to identify. It grows in tufts, is a reddish-green in colour, and the leaves are rather curled in appearance, especially when they dry out.
This rare moss is now found in only two of its former UK sites, the main one being the dune system along the Sefton coast in Lancashire, centred on Ainsdale National Nature Reserve (NNR). Coastal dune systems are listed as priority habitats under the UK Biodiversity Action Plans, and over the last few years, management at Ainsdale has concentrated on restoring much of the dune system previously lost to commercial pine plantation. As well as the moss, this habitat restoration will benefit many other specialist species, including the natterjack toad and northern dune tiger beetle.
This species has a very scattered distribution in the UK. It has been recorded from Gwynedd, Merseyside, North Yorkshire, Caithness and Angus, although it is believed to have become extinct in its Welsh, Yorkshire and Angus sites. It still occurs in Ireland, and was last seen in 2001. Elsewhere, it is found in north-west and central Europe, Iceland, Siberia and the Altai region of Russia, North America and Greenland.
The long-leaved thread moss is at risk from the lowering of the water table, and the subsequent drying out of the dunes slacks where it lives. The slacks have also been subjected to inundation by windblown sand, which also renders them unsuitable for the moss. Ainsdale NNR is also subject to a high level of public pressure, through visitors making recreational use of the extensive dunes and neighbouring beach.
Long-leaved thread moss is listed in the UK Biodiversity Action Plan, and included in English Nature's Species Recovery Programme. As with many bryophytes, collecting the information required to draw up an action plan for individual species can be difficult. Problems of accurate identification mean that past records cannot always be trusted and the true status of the plant hard to establish. Bryologists are being encouraged to look out for this and other uncommon species of moss in order to learn more about the habitat and climate requirements of this species. Once a better knowledge is gained, we will have a much better idea of just how threatened these mosses are, and how we might conserve them for the future.
The UK Biodiversity Action Plan for this species is available at UK BAP.
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