OPAL, the Open Air Laboratory, has encouraged thousands of people to get involved in recording local habitat and wildlife condition over the last few years.

The BLS worked closely with the OPAL Air Centre at Imperial College London to develop the OPAL Air Survey, a citizen science project to collect data on the distribution of common lichens which could then be related to air quality in the local area. Nitrogen pollutants, especially ammonia and nitrogen oxides, are an increasing problem in the environment so the lichen species were selected to include some that are sensitive to nitrogen compounds and others that are tolerant of them.

Many BLS members then got involved in training groups in the basics of lichen surveying and then supporting them as did their recording.

By August 2012 3700 surveys had been completed, covering much of England. There are still gaps on the map, especially in remote areas well away from the cities, and records are still welcome. Survey instructions, together with a useful identification guide, can be downloaded from the OPAL website and your records can be submitted online.

The results so far are presented as maps and charts, and former BLS President Pat Wolseley has analysed the preliminary data. She concludes that

  • Nitrogen-loving lichens are increasingly widespread in country and urban areas where nitrogen levels are high due to ammonia from intensive farming or nitrogen oxides from heavy traffic..

  • Nitrogen-sensitive lichens have been recorded in rural areas in the north, south and west of England, but they are also appearing in our towns and cities. This is most probably because of the decrease in sulphur dioxide pollution in recent years. In these areas they are often found together with nitrogen-loving lichens.

  • Intermediate lichens are present in all the areas that have been surveyed. They also appear to be returning to towns and cities where they had been absent before, as well as to country areas, and this indicates that they are tolerant of a wide range of conditions.

OPAL have recently prodcued an Urban Lichen key.