Lichens

Fungi

Fungi (Kingdom Fungi) are complex (eukaryotic) organisms that obtain nutrients from any source by digesting food using enzymes and absorbing it. Their cell walls are made with chitin. Unlike plants, fungi cannot obtain nutrients by photosynthesis. Some fungi will form an alliance with other organisms and these partners will obtain nutrients in different ways, including by photosynthesis. The best known such symbiotic relationship between a fungus and other organisms are lichens.

Lichens

Lichens are unique organisms. They live in a symbiotic relationship in which each species helps the other – a fungus protects an alga while the alga obtains food through photosynthesis for the fungus. It was discovered in 2016 that yeast is involved as a third partner in lichen symbiosis. Shape, colour, and reproduction are determined by the fungus.

Lichens are identified by growth form, colour, asexual reproduction forms, as well as the characters of the fungal spore sac tip and the fungal spores. Keys of the lichen characters are used to systematically obtain a name for the lichen. Photos help as well!

The NWT General Status Ranks list now includes all lichens ever reported in the NWT. There are 761 species of lichens confirmed present in the NWT. An additional 24 species are expected to be present.

Micro-lichens

Micro-lichens can be generally defined as lichen with a crustose growth form. Morphologically lacking a lower surface, they grow directly into their substrate. This relationship to their substrate can, using rock as an example, be over growing (epilithic) or directly within (endolithic) the substrate, with only the fruiting bodies visible above the surface. Often overlooked or mistaken as features of the rocks, soils, bryophytes, and wood where they are found, micro-lichens are abundant and diverse. Crustose lichens are estimated to represent about 75% of all lichens.

Collecting and identifying micro-lichens is more challenging compared to the larger macro-lichens. Collecting the substrate is necessary for a complete sample of the micro-lichen. As a result, a variety of tools may be required depending on the substrate. General field identifications are possible for some species, but confirmations require laboratory dissections and chemical tests. Access to a compound microscope and chemical reagents are necessary for studying these lichens.

Ecologically, micro-lichens perform several important environmental services. Rock-dwelling species contribute to weathering and soil formation. Soil-dwelling microlichens form part of the biological soil crusts that help stabilize soils from erosion, facilitate vascular plant colonization, and participate in nutrient and water cycling. The colouration of lichen thalli can influence surface albedo and affect boundary layer temperatures and water availability.

We invite the reader to contribute to improving the knowledge of lichen distribution and diversity along with sharing the beauty and importance of these species.