A love for lichens – Q&A with lichenologist Erika Hogan

Lichenologist Erika Hogan contributed to the development of the OPAL Air Survey and a number of OPAL events.

Erika's research was particularly focused on the lichen, Cladonia portentosa. OPAL caught up with Erika, to ask more about her work.

When did you first become interested in lichens?

Erika looking for lichens in heathland

I first learnt about lichens and their sensitivity to air pollution at primary school. I am fascinated by the ability of lichens to exist on every continent and survive in extreme environments.

My interest with Cladonia portentosa grew as I studied it in detail for my PhD research project.

What do you find so special / interesting about Cladonia portentosa?

Cladonia portentosa can form extensive carpets or mats and this is frequently in competition with vascular plants. A pretty impressive feat for a symbiosis between a fungus and alga.

What did your research involve? What did you find out?

My research focussed on the biology of Cladonia portentosa. In particular, I was interested in how this lichen changes in response to different amounts of nitrogen pollution in the atmosphere.

We discovered it can adapt quickly to a change in nitrogen availability and can alter physiological mechanisms to maximise efficient nutrient capture and uptake.

Erica collecting lichen samples

Why do you think it’s important for other people to learn more about Cladonia portentosa?

Cladonia portentosa is a very interesting lichen, and it has formed the basis of a lot of research projects. It is a key species for heathland habitats, which are now much less common than they once were. If we can better understand this lichen, it might help to protect areas in which it is found.

Why are heathlands so important?

Being a lichen, Cladonia portentosa lacks roots. It is typically found in low nutrient environments, and can form large ‘cushions’ in between the vascular plants typically found on heathland habitats, such as Calluna vulgaris (Common Heather).


What’s your most memorable research moment?

I spent a lot of time collecting small samples of lichens. On my very first visit to a field site in Scotland, I ended up face-first in a small brook which surrounded the site. The biggest problem? I was the one carrying the sandwiches, which came out of the brook as wet as I was.

What are the main threats facing Cladonia portentosa at the moment and what can people do to help increase numbers in the future?

One of the main threats facing Cladonia portentosa is the loss and fragmentation of heathland habitats in which it is found - particularly in central parts of England. Better education and awareness of this lichen and the general sensitivity of heathland habitats will help protect this species and heathland for the future.

If other people were interested in finding out more about Cladonia portentosa what would you advise them to do?

The British Lichen Society is a great place for people interested in lichens in general. The society is very active and always welcomes new members.