Help monitor air pollution with lichen

I have to admit that until today my familiarity with Lichens was limited to a walk on part in an evolutionary tale about peppered moths (more of that in a moment).

But the natural world never ceases to amaze. Lichens, it turns out, are not just good indicators of air quality (thriving where pollution levels are lowest), they're also two organisms for the price of one: a fungi growing in a symbiotic relationship with an alga.

Air pollution comes from a variety of sources, including cars, factories and agricultural processes.

The problem is we can't always see it, but we can measure its impact on the environment, and by building up a comprehensive picture of the distribution of lichens, scientists at Imperial College hope to create a comprehensive map of air quality across the country revealing the pollution hotspots.

And that's where you come in. Taking part is simple and fun. All you need is a copy of the survey fact sheet, and a handy guide to identifying lichens, which can be downloaded here.

Now that story about peppered moths:

During the 19th century sooty smoke from the coal burning furnaces of the industrial revolution killed much of the lichen growing on the trees and blackened the bark.

When peppered moths landed on the trees the lightest, that had been well camouflaged against the lichen, stood out as easy pickings for birds.

It created an evolutionary pressure that favoured darker moths, which became progressively more common, and by 1895 98% of the peppered moths in the vicinity of big cities like Manchester were black.

Since the 1950's when pollution controls have significantly reduced sooty particles in the air, both the lichens and lighter peppered moths have made a comeback.