Lichenology (lichens)

What are lichens?

Lichens are a symbiotic relationship between a fungus, which builds the body of the lichen (the ‘thallus') and encapsulates a population of algae or photosynthetic cyanobacteria. The main bulk of the lichen is composed of fungal material, which harvests food from its symbiotic partner in the form of photosynthetic sugars.

Close up of ‘Lobarion’ lichen epiphytes

Cross-section through a lichen thallus: the upper fawn-coloured surface is the protective 'upper cortex' (modified fungal cells), the green areas immediately below the upper surface are groups of green-algal cells, and the lower pale tissue are the fungal cells ('hyphae') in the 'medulla' (photo: Becky Yahr). 

There are an estimated 20,000-30,000 species of lichen worldwide, occupying a vast array of terrestrial and semi-aquatic habitats. Lichens are nature's extreme survivors, and are found on every continent - from the coldest parts of Antarctica, to the driest deserts, to the wettest rainforests, to the highest mountains. Despite this resistance to natural environmental extremes, lichens are sensitive to environmental perturbation, and are used as bioindicators for pollutants, climate change, and in habitat management.

Lichen growing on a log

A community of ‘Lobarion' lichen epiphytes, characteristic of Scotland's oceanic rainforests, but internationally rare (photo: Brian Coppins). 

Lichenology at RBGE

Research at RBGE combines taxonomic and ecological expertise, with studies that span the globe: from Scotland, to Nepal, by way of temperate-zone Chile, and the rainforests of Borneo and French Guiana.

RBGE taxonomic expertise has traditionally focused on the identification of diverse and difficult groups of lichens (e.g. Micarea, Bacidia, Arthonia). These skills have been applied across British and European species more widely, and RBGE taxonomy under-pins UK conservation strategy.
Ecological research examines environmental drivers of lichen diversity in Scotland, including the projected impact of climate change. Studies focus on significant European habitats that are under threat and/or poorly known: e.g. aspen woodland, juniper scrub and coastal shingle.

For more information on lichen research at RBGE, please visit our dedicated site: Lichen Biodiversity and Conservation

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