On September 12th Residents of Croydon gathered, brought together by Croydon Community Consortium and London Sustainability Exchange to explore lichens and air pollution in the Croydon area as part of Wandle Fortnight.
We gathered in Wandle Park in the early evening, first discussing citizen science and what the dangers of air pollution really are. Lichens are formed from a symbiotic relationship between fungus and algae, and grow everywhere! There are many different types of Lichens and some are sensitive to levels of Nitrogen Dioxide (NO2) in the air, therefore acting as bio-indicators of pollution levels.
We used the Opal resource which was created by the Open Air Laboratories, this is a great resource which anyone can use to survey lichen in their area (a great activity for children or school pupils). It even has a map where you can upload your results to add to the database. Be wary though Lichens can be difficult to identify so read the resource carefully!
We found a high level of Nitrogen loving lichens around the area, even in the park! Although the most developed and strongly growing ones were by the main road (A236) as you would expect. What’s really interesting when surveying is to look at how strong and developed the growth of the lichen is.
Fortunately we also found some intermediate lichens on trees near the Tudor Arch on Howley Road, which show that the air pollution is improving in the area (even if there is still a huge challenge). It will be interesting to go back and see if they continue to grow, and show as that conditions improve further.