Little jewels to find and treasure on your walk today
On my New Year’s Day walk, my eyes will not be on the white cliffs, or the dunlins pecking for molluscs in Pegwell Bay. My new enthusiasm is for an organism that is, in all its multitudinous variety, particularly visible today and during the winter months: lichen. You see more of it on trees now that the leaves are off.
Here on the Kent coast we’re used to extraordinary lifeforms, sometimes human, but lichen has an untold capacity to amaze. I’d previously thought of it as a bloom on stone, silvering the walls of a Cotswold house or blotching a rock with an orange stain. But there’s more to it than that. Lichens can be hairy, spongelike or composed of seaweed-like sheets. Leprose (powdery), fruticose (bushy), foliose (leaflike) or crustose (crusty). Father Christmas loves them: cladonia lichens are the main food source for reindeer.
Look at a lichen-covered branch or rock under a hand lens and a miniature landscape, in a rainbow of colours, appears. It’s like entering a secret kingdom, and yet it’s to be found more or less everywhere in Britain, including such inhospitable habitats as former lead, zinc and copper workings where little else will grow. Churchyards are especially rich in them. Wales, with its pure air, diverse geography (from sand dunes to mountain tops) and abundant damp, has the highest diversity of lichen species in the world.
My thanks to Tracey Lovering for this information. She’s a lichenologist. That’s quite a lonely thing to be, since there are precious few of them in the country – although they’ve got their own journal, The Lichenologist, published by the British Lichen Society. Based in Wales, Tracey wants to propagate the species through a scheme called Cennad, run by the wild flower charity Plantlife: “cen” is the Welsh word for lichen and “cennad” means messenger or envoy. I wish her well. The lichen story is important.
Lichens aren’t single organisms. They’re a mutualism – a cosy cohabitation between a fungus and an alga, to the benefit of both parties. The algae produce carbon for the fungi, the fungi provide minerals and other lifestyle advantages for the algae. Win, win. A win, too, for the country people and scientists who have harvested lichens, whether to make the red dyes in Harris tweed or exploit the medicinal properties of usnic acid (although faith in the lichen growing on an old skull as a cure for epilepsy was misplaced).
These are also indicator species. Rhizocarpon geographicum is known as the Map Lichen because the shapes that it makes resemble countries; easy to spot and relatively quick to grow, it’s used to track how fast glaciers are retreating and exposing the moraine beneath.
With their large surface area, bushy lichens are exceptionally sensitive to air pollution. Good news: there’s now less sulphur in the air and lichens can even be found in city centres. But good news can also be bad news. We don’t mine lead any more, so metallophyte lichens are in trouble. Fortunately, metal-rich furnace slag was seized upon by Victorian gardeners wanting it for their rockeries. Ecologists now value it for the lichen communities it supports. What a world of miniaturised wonder to discover: my New Year’s resolution begins with the purchase of a loupe.
read more at telegraph.co.uk/opinion