[USA] That’s not moss, it’s lichen! Next time you are on the trail, you can easily distinguish moss from lichen by getting up close and making some simple observations.
At the most basic level, moss is a plant and has plant systems such as leaves and roots, whereas lichens are not plants and therefore lack the basic plant components. So if it’s not a plant, what is lichen?
Lichen is truly nature’s love story. It takes the precise species of fungus and algae to come together, in just the right environment, to create a lichen. The two soulmates coexist in a symbiotic bond with equal cooperation, both providing vigor to the relationship.
The fungus is the protector — providing structure and safety. Algae is the nurturer — using photosynthesis to create food. Algae also determines the color of the lichen. You might question how good this relationship is when one has to do all the cooking, it almost sounds a little more parasitic than symbiotic! But this unique combination of organisms, though unusual, has many strengths.
For one, it can withstand some of the harshest environments, from extreme heat and cold to long droughts. Lichen can endure situations in which fungi or algae would die on their own, resulting in a species that can live hundreds to thousands of years, and can be viewed as a portal to history. Lichen knows the times to thrive and grow, and when to chill. This is call poikilohydry, meaning when the climate is wet, lichen will carry out photosynthesis and increase its size; and when the climate is drier, it goes dormant. This leaves behind somewhat of a timeline of climate events in the growth patterns of various lichen species, enabling scientists to read the tales from our history.
There are thousands of species of lichen across the world, making the relationship between each species of fungi and algae even more unique. Lichen can be found on tree bark, hanging from the branches, flourishing on dead logs, encompassing rocks and even casing cliff faces.
There are a few common species you can look for here in Colorado and impress your hiking buddy on your next outing with more than just fancy hiking poles. The bright chartreuse covering on cliff faces typically is pleopsidium lichen, and the small flat yellow patches on tree trunks and branches is known as candelariella.
There are many more species, an easy way to identify lichen is to take a picture and consult one of the many online lichen guides.
Not only is the lichen relationship long-lasting, they also find time to give back. Through phgotosynthesis, lichen converts carbon dioxide into oxygen. Because lichen can exist in harsh environments, they are able to photosynthesize in places that have little to no other vegetation.
Lichen are also vital to decomposition, breaking down organic materials and recycling their nutrients. Lichen is also slightly acidic, which makes the breaking down of species possible.
If lichen can survive inhospitable conditions, then why is it not abundant near cities? Just like any relationship, contaminants can spoil the love. Lichen absorbs an abundance of particulates in the atmosphere.
Examining a sample of lichen can tell lichenologists the state of the surrounding environment. Scientists use lichen to collect data on air pollution levels, by extracting metals from the lichen and determining the abundance of each component. Lichen can only withstand a threshold of pollutants. An easy indicator of poor air quality is the lack of lichen in the area.
Here in the high country, we encounter lichen all of the time. Hopefully, you took away a few new facts to wow your trail buddy if nothing else. But I can’t resist sharing one of my favorite jokes: Why did the fungus marry the algae? Because he took a lichen to her! How did the marriage end up? On the rocks.
Amanda Hewitt is the STEM coordinator at Walking Mountains Science Center in Avon. She is also currently working on her doctoral thesis through the University of Minnesota.
Photo: Rick Spitzer. The varied colors dotting this cliff face indicate different species of lichen common to the Rocky Mountains.
View original article at: Vail Daily column: A Rocky Mountain love story