Links between lichens and air quality in Co. Kildare
Nuala Madigan of the Irish Peatland Conservation Council (IPCC) looks at the links between lichen and air quality
Have you ever looked at the bark covering your local trees, and noticed what looks like staining or flattened chewing gum like markings. You might also have noticed these markings on walls in your community?
These marks are not discolouration, but actually a living species known as a lichen. Lichens are a symbiotic relationship between an algae and a fungi. Both have formed a relationship together to survive. The algae photosynthesises, making glucose, which can only be achieved by the fungi collecting the ingredients so that the algae can begin this process. There are many different types of lichen, but simply they can be divided into three categories, crustose, foliose and fruticose lichens. They are hugely important and are known as biological indicators to our local air quality. The lichen in the picture is a crustose lichen which glues itself tightly to the surface it is growing on, making it very difficult to remove. These are the most pollution tolerant of all lichens.
Their presence in a community does not indicate poor air quality as they will also live in areas of good air quality. What you are actually looking for in addition to crustose lichen are the presence of foliose and fruticose lichens. The folise lichen are also flattened, but have a more leaf like appearance and unlike crustose lichen can be removed from the surface it has attached to. This type of lichen is more sensitive to pollution than the crustose lichen and is typically found growing in areas with moderate air pollution.
To determine if you community has good air quality, you are going to be watching for the fruticose lichens, these are three-dimensional bushy looking lichens which can be observed hanging from the surface they have attached to. This type of lichen is sensitive to air pollution so their presence in a community indicates good air quality. As you enjoy your daily walk in your community this week watch for the variety of lichens.
If you would like help identifying one of your wildlife observations contact me at the Bog of Allen Nature Centre at [email protected].
- Nuala Madigan, Irish Peatland Conservation Council (IPCC), Lullymore, Rathangan