Pollution-indicator Species

1. Pollution-indicator Species Learning objectives: to know that certain species of plants & animals can tell us (indicate) how polluted an area is. to know that lichen is an indicator species, also known as bio-indicators

2. Lichen

3. Lichen

4. Lichen

5. Lichen

6. Lichen – what is it? Lichen is 2 organisms living together; a fungus and an alga (plant). They come in different sizes & shapes. Some are more tolerant to pollution than others, so their presence or absence can tell us a lot about the level of pollution in an area.

7. Lichen (Usnea subfloridana) growing on a branch of a fir tree. This lichen is a good indicator of air quality, as it is intolerant of high sulphur dioxide concentrations. A lichen is a symbiotic organism comprising a fungus and an alga. The alga produces nutrients for the fungus by photosynthesis. Photographed in western Scotland.

8. Lichen (Lecanora). This lichen is a good indicator of air quality, as it is tolerant of high sulphur dioxide concentrations.

9. Lichen (Xanthoria). This lichen is a good indicator of air quality, as it is tolerant of high nitrogen.

10. Info Usnea – only found where acid gases are low Lecanora – tolerant of high sulphur levels Xananthoria & Physcia – tolerate high nitrogen levels Acid gases – sulphur dioxide & nitrogen oxides from burning fossil fuels Fertilisers – high in nitrogen