The ‘fungi’ is creating a protective ‘body’ for the algae (hi-viz & see-through umbrella) whilst holding on to the substrate (a stick in this case). The algae, sheltering under the fungi’s protection is making ‘food’ through photosynthesis (with a wooden spoon of course!)
Lichens are extraordinary organisms.
Easily overlooked, and often un-noticed by many people, lichens colonise trees and many other surfaces (walls, pavements, railings) in our urban areas.
Did you know that lichens are made up of not one but two or more different types of organisms living together in one body! This is known as a mutually beneficial relationship where each partner benefits from the other and results in their mutual survival in places they couldn’t live so well alone.
A lichen is made up of a fungi and an algae and/or cyanobacteria
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)
Why do they live together?
Fungi can’t make it’s own food so usually relies on getting it’s nutrients from rotting materials or partnering up with other organisms in order to get food. In a lichen, the fungi provides the protective ‘home’ or body of the lichen, protecting the algae from environmental changes such as extremes in temperature, moisture and UV. This means the algae can live in much drier or more exposed habitats than it could alone.
Algae are plants and can make their own food (carbon in the form of simple sugars) through the process of photosynthesis using energy from the sun. This ‘food’ is available to the fungi and means the fungi can live in places without relying on the surface it’s growing on (known as substrate) to provide nutrients.
We hope you enjoyed the experience and that through exploring your local area in new ways detail, you discovered some new things and found out about your local air quality.
Mapping Edinburgh’s Air Quality
As part of the Edinburgh Living Landscape initiative we are hoping to build up a visual map of local air quality in and around Edinburgh using the data supplied through the feedback forms from each of the areas surveyed using thelichen survey.
To do this we need your results!
Please fill out our Feedback form. The basic feedback of results should take about 2 minutes, but if you’d like to share a bit more of your experience with us, please allow a little longer.
If you’d like more information on RBGE’s research into Urban Air Quality please click here.
Don’t forget to can use the survey more than once!
Why not try looking at a different set of trees in your local area and see if you get the same results, or go to your nearby park and have a go using the survey there.
Looking for lichens in a local park @G.Burns, TCV Scotland
You don’t have to go to a tropical rainforest, the Caledonian Forest or the far west coast of Scotland to see them, you can go on a lichen safari right here in Edinburgh and in all our urban environments.
You’ve probably walked past hundreds of them today on your way to work, school or to the shops!
Tell us what lichens you find
Next time you step outside, why not take a closer look and see what lichens you can find – take a photo, and let us know with the hashtag #myurbanlichen – don’t forget to put the location where you found the lichen!
Air pollution is a huge global environmental health issue, as recognised by the World Health Organisation. The air quality in Scotland is generally very good, however in our cities we have ‘hotspots’ that regularly exceed national and EU limits for air pollution. These limits are set because of the harmful impacts on human and environmental health.
Unlike air pollution of the past which was hard to ignore, because it was smelly and visible as smog, today air pollution is almost invisible. This means we often forget about it. We can overlook the negative impacts it has on our health and the health of the environment.
Lichens & Air Pollution
‘Bushy’ lichens are very sensitive to air pollution and are therefore a sign of good air quality.
Lots of different species of lichen can also be an indicator of good air quality.
Lichens are extraordinary organisms. Un-noticed by many people, they colonize trees (and many other surfaces) in urban areas. Most lichens are very sensitive to air pollution (because they absorb everything they need to live and grow directly from the atmosphere and have no mechanism to control and filter out harmful toxins found within the atmosphere) and can therefore be used as indicators for environmental health and local air quality.
Lichens can make invisible air pollution visible.
In clean air environments trees will be covered in lichens, not bare like this one next to a busy road.
The idea formed quite early on in my TCV Natural Talent Traineeship based at the Royal Botanic Garden Edinburgh to develop a specific tool kit to help people engage with the concept of ‘biodiversity leading to environmental & human well-being‘. The ‘tool kit’ uses lichens as indicators of air quality to help us explore the links between people, place, lichens, air pollution and active travel.
It is long been documented that the humble lichen is highly sensitive to various air pollutants. During my traineeship I have been exploring how air pollution, in Edinburgh and surrounding areas within the eastern central belt of Scotland, affects lichen populations and lichen species growing on the trees within our urban areas. The aim was to discover what the lichens we do or don’t find can tell us about our local air quality.
The result of this scientific enquiry, robust data analysis and lots of public engagement research has been the:
Lichens – Making the Invisible Visible – An Air Pollution Survey
Exploring ‘crusty’ lichens growing on trees in Prince’s Street Gardens Edinburgh
The survey is an introductory level survey, aimed at individuals, community groups, families, and anyone interested in exploring their local air quality – which may then lead into doing the OPAL Air Survey.
The survey links directly to where people are, to their local areas, local pollution sources and their local air quality.
Using experiential learning (learning through exploring, experiencing, creating, discovering, relating to and interacting with the world around us), the survey gets us to really explore the air we breathe, our local areas (through physical and sensory mapping), local sources of air pollution, and doing a very simple lichen ‘hunt’. It then helps us to explore how we can help improve our local air quality & also work towards reducing CO₂ emissions by taking part in Active Travel (walking, cycling, public transport – supported by Sustrans).
This is a citizen science survey which focusses on process – exploration, discovery, sharing and critical thinking, which aims to enable increased awareness of our local areas and the impacts of our actions, leading to positive behaviour change. In this survey the ‘results’ of the lichen hunt are not uploaded onto a national data set but are immediately fed back to the individual/groups conducting the survey.
Lichens are everywhere “right under our noses”!
Teachers & Facilitators
The survey can be completed in single short session or several lessons/sessions could be developed around the themes explored.
Activities within survey can cover Experiences & Outcomes of literacy, numeracy and health & wellbeing—engaging the subjects of Science, Expressive Arts, Social Studies and Health & Wellbeing.
How a particularly grand piece of street furniture such as this one has not been captured on Google Maps I do not know…
Almost invisible to the casual viewer eye with it’s coffee coloured exterior this Automatic Air Monitoring Station blends right in against a back drop of the beautiful honey coloured buildings of the historic town of Linlithgow.
What occurs to me though is: does the amazing array of street furniture so many high streets have replace the spaces where once their might have been trees?
A trip to the borders ensued for this surveying site – with Peebles being my destination.
After a beautiful but rather bumpy breezy trip on the front seat of a double decker bus with a poorly fitting front window, I make my way through the back streets of Peebles to the local council and police station grounds.
A cleaner air environment – Melanohalea exasperata
I expected this to be a cleaner air site and therefore lichen identification to be a tad more challenging due to increased diversity of species. I am not wrong. Although it doesn’t have the mind-boggling diversity of lichens found at the nearby Dawyck Botanic Garden, it certainly does have a richer community of lichens than I have found at many of my urban sites. The tree trunks are dominated by a healthy population of Hypogymnia physodes (less pollution tolerant) and Parmelia sulcata as well as Parmelia Saxitalis, with only a tiny amount of the nutrient-loving Xanthoria species creeping in. I also found the very beautiful Melanohalea exasperata on the twigs of one of the trees.
I was excited to add a new species to my survey lists so far – Hypocenomyce scalaris, a scurvy looking fellow hanging out at the bottom of one of my survey trees. And on the ground in amongst the grass near my survey trees, a glorious covering of the leafy (foliose) Peltigera lichen (commonly known as the Dog Lichen due to it’s fruiting bodies – sexual reproduction, looking at little like dog’s teeth – it was thought to cure dog bites according to the Doctrine of Signatures).
There are aproximately 91 species of Peltigera in the family Peltigeraceae. Peltigera often grow on soil (terricolous), but can also occur on trees, rocks, moss and a variety of other substrates in many parts of the world. They provide vital micro-habitats for a wide variety of wildlife and add important biodiversity to a grassland or lawn.
Highly nutrient-enriched bark shown by the presence of Xanthoria parientia
A train and bus ride see me heading out west to a air pollution monitoring station out on the edge of a small town. My bus stop is the last before open countryside…I’m helpfully informed by a local resident that the area – Coneypark comes from ‘coney’ the old Scottish name for rabbit. I don’t see any rabbits in my brief visit but plenty of horses in the nearby fields.
The trees I am to survey are either split trunked by nature or through coppicing and they are laden with lichen species Xanthoria. This species has been shown to be highly indicative of nitrogen enrichment – and in this case, with the site positioned on a main road with farms nearby, pollution in the form of nitrogen dioxide (NO2) probably originates from passing motorised vehicles, and nitrogen enrichment in the form of ammonia (NH3) from the nearby agriculture and livestock.
Automatic Rural & Urban Air Quality Monitoring Station at Falkirk Banknock
Surveying in Alloa as part of my project Lichens as Air Quality Indicators led me to a local police station. This is not my first encounter with the police whilst surveying (See blog from Linlithgow – coming soon)
The air pollution monitoring station is situated on the Alloa Ring Road, and according to Scottish Air Quality the location has been chosen as ‘worst case’, due to the busy road, pedestrian crossing and residential properties nearby.
The closest trees are tucked behind a low wall in the grounds of a police station, and I am kindly allowed to hang out for several hours making my surveys of the trees – a mix of maple and cherry. ON one side of the thin piece of land is the busy ring road, on the other a railway track. As a consequence I find much of the tree branches and trunks quite black from pollution, both historic and current I imagine.
I find the classic dust & nutient-loving lichen community of Physcia, Xanthoria and Candelariella species, as well as the distinct Ramalina farinacea, which of the ‘bushy’ lichens is the most tolerant of air pollution.
Cherries in full bloom in Stirling @accommodationbedscotland
Under a glorious canopy of blossom I find the Stirling’s automatic air pollution monitoring station, (part of the Automatic Urban & Rural Network). A rather battered looking station, but touched by the beauty of overhanging laden boughs. Unfortunately my previously trusty camera suddenly decided to totally give up the ghost and left be bereft and sadly lacking in my own photos of the day.
Poised amidst this pink haze of blossom I start surveying the lichens on the cherry trunks, barely aware of the busy road and roundabout a mere couple of metres away from me. About half a metre away from me in the other direction is a busy footpath, and my curious nose pressed to bark close inspection of these tree trunks generates quite a bit of interest with several people doing double takes at my antics and a few brave souls even asking me some questions. Two locals even joined me in picking up a handlens and taking a closer look themselves at their local lichens.. some lovely ooohs and wow’s followed!