November always finds me with a thermos of tea or hot chocolate heading into the woods with my dogs, layered up in flannel and fleece, mitts and a warm hat. The days almost guarantee that you will see your breath in the air, the last of the leaves have fallen from the first couple of storms and winter is fast approaching. One break of a branch seems to echo as everything is amplified without the padded insulation of leaves and life everywhere, yet there are amazingly brilliant clumps and sprawling growths hanging from the trees and swaying in the breeze.
Lichen, often confused with moss but completely different in anatomy, is a wondrous, almost magical life form that lives year round in our forests. Although they are both non-vascular, mosses are plants that have roots and stems and are very normal specimens with chloroplasts throughout their entire structure allowing photosynthesis from all directions.
Strangely enough, lichens do not have roots or stems or leaves and it is amazing that they are even considered a living thing! Lichens are actually not a plant at all and they only have chloroplasts on the very top or surface, limiting the ability for photosynthesis.
Despite moss and lichen being completely different, they often share similar habitat. Mosses retain water, and the lichen use that to prolong their growth, making it very common to see them growing together even on the same tree.
Lichens are a combination of two organisms, a fungus and an alga, that work symbiotically in a very complex relationship, and no two lichens are the same. The fungus is the dominant half, and it gives the lichen its unique characteristics like the specific shape of its fruiting bodies. The alga that works with the fungus can either be green or blue-green cyanobacteria, or often both harmoniously. The alga is responsible for photosynthesis which provides food to the fungus, allowing it to spread and grow.
With approximately 17,000 species of lichen worldwide, and about 3,600 species right here in North America, Lichens are found in a wide range of climates and habitats from the alpine tundra to tropical rainforests to deserts and coating rock faces in barren landscapes. You may have seen crust lichens full of colour embracing the harshest cliffs and crags of the Rocky Mountains. Or in the dense rainforest of Vancouver Island you will see wispy witches’ hair gracefully sweeping through the branches.
“Lichens don’t fight the cold, dry winter air. Unlike wintergreen leaves, they have no waxy coating to slow evaporation. They don’t hide roots deep in the unfrozen ground like the oaks. In fact, lichens have survived at least 18 months in the hostile environment of outer space.” – Emily Stone, Naturalist / EducatorCable Natural History Museum.
With the fungus portion of the lichen, it is able to protect the alga and therefore can exist in very harsh conditions including dry, sunny environments as long as they get some rainfall or flooding to recharge once in a while. Lichens get all of the nutrients they need to survive from the air around them and the rain that falls. It is so resilient that it is usually the first organism to appear after a natural disaster such as a fire or flood.
Since lichens promote algae growth in so many different climates throughout the world, they are one of the most important organisms responsible for converting carbon dioxide from the atmosphere into oxygen through the process of photosynthesis. They can also absorb harmful pollutants such as heavy metals and sulfur. This extracting process is referred to as “biomonitoring”.
Lichens actually provide us with valuable information about our environment. The thallus of the lichen absorbs the pollutants in the atmosphere and scientist can then extract the toxins from the lichen and determine levels of individual pollutants in an area. It serves as a ‘registry’ current sample of air quality. This allows for studies of ecological impacts especially in metropolitan or well developed areas.
Lichen will actually stop growing in areas that they once grew if the air becomes too polluted. Many city parks with preserved forests have been stripped of their lichens because they cannot tolerate the amount of air pollutants. So the next time that you take a walk, make note of the amount of lichen in the area.
Fanny Bay has lots of different varieties of lichen, so keep your eyes out! It means that you are in an area of good air quality, and low pollution. One more reason to be thankful to be here!
By Angela Hicke – Van Isle Wild
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