From the summits of some of the world’s highest mountains and the extreme cold of vast, icy polar landscapes, to the intense heat of seemingly barren deserts and humid, crowded tropical rainforests, as well as the seasonally varied climate of temperate deciduous woodlands and the exposed salty conditions of rocky coastlines, a small amount of exploring, of paying attention to detail and of looking closer at the landscape will reveal a varied abundance of wonderful, curious organisms. Lichens.
This collection of photographs and information shows a tiny amount of the spectacular diversity of lichens. Enjoy!
It is estimated that the total number of lichen species on Earth could be as many as 30, 000.
A quarter of the 1,873 different species found in Britain could be growing in a single ancient Scottish woodland.
Lichens are an important part of ecosystems all over the world, as a food source for animals such as reindeer in the Arctic, as a nesting material for birds including goldfinches, as camouflage for insects like the peppered moth, and as a home for a variety of spiders, mites and lice.
Lichen is made up of two different organisms – a fungi, and a photosynthetic partner, either an algae or a cyanobacterium. The fungus part of a lichen is completely unique to that lichen, while the algae or cyanobacterium may be found in several different species.
“Lichenometry” is used to determine the age of a surface on which a lichen is growing. It involves measuring the radius a of species of lichen which grows outwards in a circle shape. Using this measurement together with the growth rate of the lichen per year, the age of the lichen and therefore the age of the surface on which it is growing can be calculated. Lichenometry is used in this way to track the retreat of glaciers.