Ecological hiking trail – Stop 06
|God sleeps in a stone, he breathes in a plant, he dreams in an animal, and awakens in man.
Plants and animals around the Church St. Joseph: survivors of the town
Some living beings have accompanied the church St. Joseph since its foundation: especially lichens living on the base of the church or in its interstices. Although they grow very slowly (1-2 mm a year in our region!), lichens are extremely long-lived. But why do we often overlook these plants? Lichens living on stone are often called crustoses. Because of their often grey color, their flat form, and their crusty texture, they are inconspicuous. In addition, they tend to live in places where nobody would expect their presence: on stone such as rocks, boulders, gravestones, or granite pillars. These crustoses stick with their backside to the surface. Other lichens, such as bush lichen (a subspecies of which is the beard lichen found on poles) and foliose lichens, which mainly grow on trees or on the soil, are attached to the surface with their tiny filaments.
It is estimated that there exist about 16,000 distinct species of lichen, 2,000 of which are native to Europe. These numbers make it extremely difficult to exactly determine species of lichens. In most cases, an expert must look each specimen under the microscope.
Only 100 years ago, humans discovered that lichens are not just simple plants such as moss. Lichens are symbiotic associations of a fungus with a partner. This partner is, most of the times, green algea, but it can be blue, brown, and red algae as well. Algae produce food (carbohydrates) for the lichen from sunlight by way of photosynthesis. The fungus, in turn, provides algae with water and minerals, thus protecting it from dehydration.
Talking of dehydration: lichens are natural born survivalists. They are able to adapt to extreme climates and harsh environments such as deserts or the Antarctic zone. The reason can be found in the fact that lichens are able to live on the humidity in the air. But this may also turn to a disadvantage since the slightest change in air quality can have disastrous effects on lichens.
Klaus Hirn, Karl Prell, Christian Wolfram