On the trail leading to the cave, crusty red, green, grey, and orange lichens can be seen growing on bare rock. As you see them, please do not attempt to remove them because they grow at extremely slow rates. On average, they will enlarge 0.1 to 1 millimeter a year.
Lichens are composed of both fungus and algae that live together in a beneficial relationship. The alga provides food for the fungus, and the fungus retains water for the algae. By helping each other out they form lichens that can live in extreme environments
Lichens are useful in many ways. Humans use them to create color dyes and perfumes. Small insects create shelters and nests within them. Lichens are also partially responsible for the initial soil break down after disasters such as slope movement.Lichens are indicator species, meaning that they indicate whether or not the environment is healthy. They are extremely sensitive to air pollution and will not grow where there are too many pollutants in the air. For this reason, scientists use lichens to measure the degree of health in many different environments.