Often overlooked, Lichens serve many functions in the natural environment. Not only are they good indicators of environmental health, but they also support wildlife. Known as a “keystone” species, lichens are vital to the well-being of the entire ecosystem. Late winter/early spring is a great time to take a walk and keep an eye out for the many different types growing in New Jersey.
Lichens can be found growing on trees, rocks, soil, metal,
plastic, cloth, etc. They are living organisms that function as a symbiotic
combination of fungus, algae, and yeast. The algae provides nutrients through
photosynthesis, the fungi protects the algae from drying out, and the yeast
allows the lichen to produce an acid that protects it from microbes.
Lichens can be beautiful and take on many shapes depending
on the type. The three main groups of lichens include: crustose (crusty),
foliose (leafy), and fruticose (bearded or tubular).
Perhaps the biggest reason for lichens’ likability is that lichens are indicators of good air quality. They are used as bio-monitors and give scientists clues about environmental pollution levels. Most lichens will not tolerate air pollution, they require clean air. They may die if exposed to elevated levels of sulfur or heavy metals. According to the National Park Service, “Lichen trap particulate matter in the air like dust, while also absorbing smaller pollutants like sulfur, mercury, and nitrogen. This means cleaner, healthier air for us to breathe.”
In 2015, two species of lichens were removed from the Rutgers
Pinelands Field Station and moved to the New York Botanical Garden in New York
City. But, more than two years after the move, the lichens met their demise.
Researchers attributed their non-survival to both disturbance and exposure to higher levels of air pollution than was present in their previous habitat in southern New Jersey.
Contrary to a popular misconception, lichens do not harm trees. They do not feed on tree bark. Lichens are not a sign that a tree is damaged, dying, or diseased. They are found, however, on slow-growing, often mature trees. In this way, they can be an indicator of declining health of the tree because the bark has become brittle and cracked or the tree has defoliated. The lichens are not damaging the tree, simply using the bark as a place to exist and collect sunlight.
Fun Facts about Lichen:
- Lichens occur in all habitats, including arctic, rainforests and desert.
- Ruby-Throated Hummingbirds use lichen to line their nests.
- Lacewing insects carry lichen on their backs as camouflage.
- Lichens are a food source for deer, birds, and rodents.
- Scientists can use certain slow-growing lichens to estimate the age of rocks, glacial retreats, and landslides.
- Humans throughout history have used lichens in food, to dye clothing, and as medicine.
- Some lichens can live for centuries.
- There are approximately 3,600 species of known lichen in North America.
The next time you are out for a walk, take a moment to notice the abundant and different types of lichens. Now you know more about them, you may find yourself breathing a bit easier and liking lichens a bit more.
Rutgers Cooperative Extension Fact Sheet: “Tree-Dwelling
Lichen”
https://njaes.rutgers.edu/fs1205/
University of Maryland Extension: “Lichen, Algae, and Moss
on Trees”
https://extension.umd.edu/resource/lichen-algae-and-moss-trees/
US Forest Service: “Lichen Biology”
https://www.fs.usda.gov/wildflowers/beauty/lichens/biology.shtml
Us National Park Service: “Lichen-The Little Things that
Matter”
https://www.nps.gov/articles/lichen-and-our-air.htm
New York State Parks Blog: “Likin’ the Lichens in New York
State”
https://nystateparks.blog/2017/05/09/likin-the-lichens-in-new-york-state/
New York Botanical Garden Blog: “New Jersey Lichens Give Up
the Ghost”
https://www.nybg.org/blogs/science-talk/2018/01/new-jersey-lichens-give-ghost/
