Lichens

I have realised I have an annual pattern of making things in the winter. I didn’t realise until now, but every December when the cold and rain stop me from working in the soil, I turn my attentions to being creative indoors. 

A couple of years ago I made hypertufa pots out of cement and peat and last year I made hemp pots. Both of these ventures were enjoyable but ended by me cluttering up the garden with enough pots to start a business. This year I decided to turn my attention to making some supports for my ever growing collection of air plants.  As these plants have no roots as such, all that is needed is for something to hold them in place. 

As I have a bit of difficulty getting my hands on some bogwood I thought driftwood might be a simpler choice and is easier to work with as most of it isn’t petrified 5000 year old roots. Over a few weekends I scoured the shoreline and ended up with a garage load of wet, salty twigs and stems, some of which weren’t eaten by the dogs before the dried out. I did have a pile of wood on the fireplace for a while and it’s amazing what crawls out of the knot holes as they are drying. Mostly armoured woodlice, but there are a few things I haven’t seen before. Watching their bid for freedom gives me something to watch in my quieter moments.  To embellish the wood and give it a more natural, weathered look, I thought I would harvest a bit of lichen from the woods.  Lichen should be easier to work with then moss as that’s messy and more at home in a hanging basket.

I was amazed at the huge variety of colours and textures of this mysterious plant.

What are Lichens?

Lichens are a compound organism in which a fungus lives together in symbiosis with an alga and/or bacteria. Together each combination forms a stable union with both organisms benefiting from each other. The algal (and/or cyanobacterial cells) are protected from drying out by the enveloping fungi, which also provides attachment to the rock, wood, soil or other substrate. In return, the fungus receives nutrients from the alga, in the form of sugar made by photosynthesis.

It is estimated that nearly 8% of the earth’s land surface is covered by lichens. This enables them to make a significant ecological contribution by generating carbohydrates through photosynthesis which helps to reduce carbon dioxide levels and fixes nitrogen.

Ice Age History

Many lichen species appeared to have stayed in Ireland during its last Ice Age, particularly in areas where rock remained exposed to the air. As the Ice Age retreated (about 13,000 years ago) trees reappeared in Ireland bringing a rich lichen flora with them.

Today it is estimated that there are about 1200 lichen species on the island. This rich biodiversity is due mainly to the many distinct habitats (from rocky seashores to pockets of mixed woodland to mountain areas) here and the temperate damp climate.

West of Ireland woodlands and bogs are still the best places to see the remnants of species that must have been abundant here in ancient times. We can see loads of examples here in inishowen, especially in the older woodlands.

Old Growth Forest Indicators

Some lichens are poor dispersers and are slow to populate new habitats. Such species tend to stay and flourish in a single habitat such as a forest. These lichens are called old-growth forest indicators.

Lichens are part of an ecosystem’s primary producers and they are a source of food for many organisms from tiny invertebrates to large vertebrates. There is little doubt that in ancient Ireland the Elk would have fed on lichen species such as Reindeer moss (Cladonia species). Ireland does not have a high enough lichen biomass to support mammals today.

What uses lichen?

Apart from me in the displays, squirrels use lichens to line the inside of their nests. Birds use lichens to patch the outside of their nests to camouflage them as well as using them for food. Birds play an important part in dispersing lichen.  The reproductive bits of the lichen (soredia) are small and light enough to stick to bird’s feet and feathers so are carried to other trees and habitats. Moths and butterflies feed on lichens and use them for camouflage.

Many lichens, have a rich biodiversity of invertebrates associated with them. As lichens are good bio accumulators and part of an ecosystem’s food chain they can store and pass on nutrients efficiently.

It’s funny but the more I get to find out about this fascinating plant, the less inclined I am to want ot use it in decorations. It seems a bit of waste until I remind myself that if I put the lichen outside again, it’ll probably start growing again. It’s probably one of the hardiest plants you can get, as long as we have damp and clean air. Thankfully we have plenty here.