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Extrait du documentaire Quelques raisons d'espérer, dans lequel Pierre Dansereau explique, en présence de Louis-Edmond Hamelin, ce qu'est un lichen et son importance dans un écosystème, [entre 1999 et 2001].
Réalisation : Fernand Dansereau.
Université du Québec à Montréal. Service des archives et de gestion des documents.
Fonds d’archives Pierre-Dansereau, G.86.31.

Fernand Dansereau : Action ! Pierre Dansereau : Lichens play an important role in almost all ecosystems of the world. A lichen, as it’s well known, is the result of the symbiosis of the living together of an alga and a fungus. The alga is capable of using solar energy through photosynthesis and the fungus fabricates sugars and hydrocarbonates. The lichens almost everywhere play a pioneer role. They are very frequently the first to establish contact with a non living world, with the bare hard rock. They are able to cover the rock almost sometimes completely, almost completely here, as can be seen. There are various forms and colors: these lichens, these black lichens, absorb a lot of heat of course, and they have the form of a crust. Where as other lichens are like leaves and they live on trees as epiphytes, or they cover the ground such as the caribou lichen in the taiga, south of here near Kujuak for instance. They form a complete carpet and they are the principal food of the caribou through many months of the year.

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