Why I'm looking for lichens/ Some lichen info on air quality, habitat etc..

 As epiphytes, lichens have evolved to depend on being able utilize many of the chemicals they process from the moisture and the air around them. Most species of lichens prefer a cleaner, more natural air and often thrive better in places that are not industrially polluted. Some species of lichens can tolerate a greater degree of pollution  than others. A lack of diversity of lichens, or a scarcity of lichens of where they were once found, can be one indicator that can be explored to see if air pollution is contributing to this scarcity. Lichens can be interesting to people concerned about monitoring air pollution because some of the chemicals they have stored can be analyzed by using living samples.

Lichens range over most of the natural places in the world. Although many species of lichens appear to me to prefer places with a lot of moisture, lichens are able to shut down some of their processes so that they can adapt to a climate with more or less moisture. They can tolerate temperatures that range from having permafrost to places that one would consider much hotter, if not just as dry. Lichens can be found in artic tundra regions and although they may not tolerate heat to the extremes they can of cold or moisture,some lichens can even be found in the dryer areas like deserts for instance, by gathering the moisture that they need in the form of dew. Lichens can go tropical.  Lichens have been found the the ocean and can be observed at inter-tidal zones, they can be seen in many different and varying climates around the world, of forests, on hill sides, on mountains, fields, beside rivers, and many other varied and interesting places.

  Lichens are not technically a plant. They are classified under the fungi. This fungus exists most commonly  with a photosynthetic algae and/ or a photosynthetic bacteria. I found that their relationship is currently being explored more in depth to try and understand their relationship. It may not be quite so symbiotic as we once believed. Some scientists describe their relationship as being a lot more favorable to the fungi.  Lichens may grow slower compared to many of the plants that we see around us. They also need time to establish themselves.

 I have found lichens on some of the trees in my area, by looking at tree trunks and on the branches. Lichens can also be found on the soil. I have looked for them on bare rocks, downed trees and on wood debris. I have read that Lichens have been found on many unusual substances and places including animal bones, plastic, metal and other materials. Old buildings, older stone fences, and older stone grave markers can be good places to think about when trying to find an assortment of lichens to photograph. Rock cliffs, rock slides and standing rocks are also good places to explore.

 An amazing variety of animals eat lichens. Some owls and other birds will eat lichens. I found through looking on the internet that birds can use lichens as part of their nesting materials.I discovered that lichens can be a valuable food source for wild life that live in my area and can help some animals to find subsistence food particularly in the winter.

For more on air quality monitoring see
Environment Canada. Monitoring Lichens. from ec.gc.ca/
Natural History Museum .nhm.ac.uk/ nature-online/plants/fungi/lichens
nasce.org. National Lichens and Air Quality Database.
fs.fed.us. National Forest Service, USA,