Scaly breck lichen  (Squamarina lentigera)

Classified as Endangered in the UK.

This rare lichen is circular in shape, and white to pale grey-brown in colour.

This species is found across most of Europe, from Norway to the Mediterranean, in North America, North Africa and Asia. In the UK it used to be found in East Sussex and the Isle of Wight, but is now confined to just two sites in the East Anglian Breckland.

Scaly Breck lichen is a ground-dwelling lichen, found on sandy, calcareous soil, which is disturbed regularly. Breckland is an area some 1500 square kilometres in extent, characterised by a dry climate, and well-drained light soil. The poor quality of the soil has produced a unique habitat where small, specialist plants and lichens flourish.

This lichen is one that grows on the surface of the soil rather than stone or rock. Like most lichens, it is slow-growing and needs a bare area to colonise. It cannot compete with tall plants and requires grazing, either by sheep or rabbits, to maintain a closely cropped sward in order for it to survive.

This species has declined through loss of habitat, largely due to a fall in the rabbit population through myxomatosis. This has led to a lack of grazing and reduced opportunities for colonisation of new areas by the lichen. Spray drift from neighbouring farming activities may also pose a threat. There could also be an indirect impact through ammonia and other nitrogen compounds increasing the vigour of the surrounding vegetation, and reducing the areas of open ground the lichen requires.

Scaly Breck lichen is listed in the UK Biodiversity Action Plans (UKBAPs), and is included in English Nature's Species Recovery Programme (SRP). With any species of plant and animal in decline, it is vital to establish what has or is happening to reduce its numbers. Research has determined the causes for this lichen's reduction in populations, and all its existing sites are now protected. It has also been successfully re-introduced to suitable sites within its former Breckland range. Lichens are easily overlooked, yet they are fascinating organisms. It is just as essential that they receive protection, and that efforts are made to conserve them, as any of the more glamorous and well-known species in the British Isles.

• Calcareous: containing free calcium carbonate, chalky.