Lichens, how old are they?


This July 2019 video from Britain says about itself:

“What actually is a lichen?” In this film, we learn about the structure and function of lichen, as well as the three main growth forms and how to identify different lichen forms. Lichenologist Joe Hope invites us to have a closer look at the fascinating lichen ecosystem especially the relationship between lichen and algae. He clearly explains some key terms that will help you understand more about the lichens in your local woodland.

A film for woodlands.co.uk by Jemma Cholawo

From the Field Museum in the USA:

Lichens are way younger than scientists thought

November 15, 2019

You’ve probably seen a lichen, even if you didn’t realize it. If you’ve ever meandered through the forest and wondered what the crusty stuff on trees or rocks was, they’re lichens, a combination of algae and fungi living together almost as if they were one organism. And since they can grow on bare rocks, scientists thought that lichens were some of the first organisms to make their way onto land from the water, changing the planet’s atmosphere and paving the way for modern plants. A new study in Geobiology upends this history by delving deep into the DNA of the algae and fungi that form lichens and showing the lichens likely evolved millions of years after plants.

“When we look at modern ecosystems, and we see a bare surface like a rock, oftentimes lichens are the first thing to grow there, and eventually you’ll get plants growing on there too,” says Matthew Nelsen, lead author of the paper and a research scientist at the Field Museum. “People have thought that maybe that’s the way ancient colonization of land worked, but we’re seeing that these lichens actually came later in the game than plants.”

Four hundred and eighty-five million years ago, Earth was very different from what we see today. Hardly anything lived on land. But lichens can live in extreme conditions. They can grow on bare rocks and break them down, helping to create the soil needed by complex plants with roots (called “vascular plants”). Scientists thought that lichens must have arrived on land before the vascular plants did and made the environment more hospitable. But Nelsen and his colleagues’ work calls this timeline into question.

Nelsen didn’t set out to disrupt lichen’s status as some of the land’s first colonizers. He was initially interested in finding out how the algae-fungus relationship that makes up lichens came to be. If lichens could update their relationship status on Facebook, it would definitely be “it’s complicated.” They’re a product of symbiosis, a relationship where two species live together and both benefit. In this instance, the algae — or specialized blue-green algae called cyanobacteria — provide food and the fungi wraps around it creating a shelter. “The question of when lichens evolved and how many times fungi evolved the ability to form symbiotic relationships with algae has been a bit contentious in the past,” says Nelsen.

But to accurately determine when lichens evolved, scientists needed to examine the evolutionary history of both the fungi and algae that make them up. The early lichen fossil record isn’t very clear; it can be hard to tell lichen fossils apart from other fossils, and all the fossils that scientists know for sure are lichens are younger than the oldest complex plant fossils. So, the researchers used the fossils that were available to extrapolate the ages of family trees of lichen-forming fungi and algae. They compared these family trees with ages of fossil plants. The verdict: lichens probably evolved long after complex plants.

“Lichens aren’t as old as we thought they were. They’re a younger, newer sort of symbiosis and haven’t been around forever, covering the earth long before there were plants and animals running around,” says Nelsen.

Unearthing the age of lichens makes it clear that the pattern of modern lichens showing up on rocks before plants doesn’t mean that lichens evolved before plants. “It provides a snapshot into what was going on deep in time on Earth, and when some of these groups started appearing,” says Nelsen. And since lichens growing on soil can make the ground wetter, hold the soil in place, and influence the kind of nutrients present in soil, learning when lichens arrived on the scene use us a clearer picture of the world in which complex plants evolved.

By understanding what the Earth was like hundreds of millions of years ago, we can examine how it’s changed and gain more insight into the current state of our planet. For the researchers, it’s similar to the feeling you might get when learning about your family history from an ancestry DNA kit.

“It reshapes our understanding of the early evolution of complex ecosystems on Earth,” says Nelsen.

Dinosaurs extinct, lichens survived


This 25 January 2018 video says about itself:

What’s in a Lichen? How Scientists Got It Wrong for 150 Years | Short Film Showcase

For 150 years, scientists believed lichen were defined by a symbiotic relationship between a fungus and algae. Meet the team of researchers who upended this belief in this short film by Andy Johnson, Talia Yuki Moore, Chris A. Johns, and Kate Furby.

From the Field Museum in the USA:

When the dinosaurs died, lichens thrived

Mass extinction hurt land plants, but DNA shows that some fungus/plant combo organisms rose up

June 28, 2019

Summary: When the asteroid hit, dinosaurs weren’t the only ones that suffered. Clouds of ash blocked the sun and cooled the planet’s temperature, devastating plant life. But fungi, which decompose dead stuff, did well. So what happened to the lichens, which are made of a plant and fungus living together as one organism?

When an asteroid smacked into the Earth 66 million years ago, it triggered mass extinctions all over the planet. The most famous victims were the dinosaurs, but early birds, insects, and other life forms took a hit too. The collision caused clouds of ash to block the sun and cool the planet’s temperature, devastating plant life. But a new study in Scientific Reports shows that while land plants struggled, some kinds of lichens — organisms made of fungi and algae living together — seized the moment and evolved into new forms to take up plants’ role in the ecosystem.

“We thought that lichens would be affected negatively, but in the three groups we looked at, they seized the chance and diversified rapidly,” says Jen-Pang Huang, the paper’s first author, a former postdoctoral researcher at the Field Museum now at Academia Sinica in Taipei. “Some lichens grow sophisticated 3D structures like plant leaves, and these ones filled the niches of plants that died out.”

The researchers got interested in studying the effects of the mass extinction on lichens after reading a paper about how the asteroid strike also caused many species of early birds to go extinct. “I read it on the train, and I thought, ‘My god, the poor lichens, they must have suffered too, how can we trace what happened to them?'” says Thorsten Lumbsch, senior author on the study and the Field Museum’s curator of lichenized fungi.

You’ve seen lichens a million times, even if you didn’t realize it. “Lichens are everywhere,” says Huang. “If you go on a walk in the city, the rough spots or gray spots you see on rocks or walls or trees, those are common crust lichens. On the ground, they sometimes look like chewing gum. And if you go into a more pristine forest, you can find orange, yellow, and vivid violet colors — lichens are really pretty.” They’re what scientists call “symbiotic organisms” — they’re made up of two different life forms sharing one body and working together. They’re a partnership between a fungus and an organism that can perform photosynthesis, making energy from sunlight — either a tiny algae plant, or a special kind of blue-green bacterium. Fungi, which include mushrooms and molds, are on their own branch on the tree of life, separate from plants and animals (and actually more closely related to us than to plants). The main role of fungi is to break down decomposing material.

During the mass extinction 66 million years ago, plants suffered since ash from the asteroid blocked out sunlight and lowered temperatures. But the mass extinction seemed to be a good thing for fungi — they don’t rely on sunlight for food and just need lots of dead stuff, and the fossil record shows an increase in fungal spores at this time. Since lichens contain a plant and a fungus, scientists wondered whether they were affected negatively like a plant or positively like a fungus.

“We originally expected lichens to be affected in a negative way, since they contain green things that need light,” says Huang.

To see how lichens were affected by the mass extinction, the scientists had to get creative — there aren’t many fossil lichens from that time frame. But while the researchers didn’t have lichen fossils, they did have lots of modern lichen DNA.

From observing fungi growing in lab settings, scientists know generally how often genetic mutations show up in fungal DNA — how frequently a letter in the DNA sequence accidentally gets switched during the DNA copying process. That’s called the mutation rate. And if you know the mutation rate, if you compare the DNA sequences of two different species, you can generally extrapolate how long ago they must have had a common ancestor with the same DNA.

The researchers fed DNA sequences of three families of lichens into a software program that compared their DNA and figured out what their family tree must look like, including estimates of how long ago it branched into the groups we see today. They bolstered this information with the few lichen fossils they did have, from 100 and 400 million years ago. And the results pointed to a lichen boom after 66 million years ago, at least for some of the leafier lichen families.

“Some groups don’t show a change, so they didn’t suffer or benefit from the changes to the environment,” says Lumbsch, who in addition to his work on lichens is the Vice President of Science and Education at the Field. “Some lichens went extinct, and the leafy macrolichens filled those niches. I was really happy when I saw that not all the lichens suffered.”

The results underline how profoundly the natural world we know today was shaped by this mass extinction. “If you could go back 40 million years, the most prominent groups in vegetation, birds, fungi — they’d be more similar to what you see now than what you’d see 70 million years ago,” says Lumbsch. “Most of what we see around us nowadays in nature originated after the dinosaurs.”

And since this study shows how lichens responded to mass extinction 66 million years ago, it could shed light on how species will respond to the mass extinction the planet is currently undergoing. “Before we lose the world’s biodiversity, we should document it, because we don’t know when we’ll need it,” says Huang. “Lichens are environmental indicators — by simply doing a biodiversity study, we can infer air quality and pollution levels.”

Beyond the potential implications in understanding environmental impacts and mass extinctions, the researchers point to the ways the study deepens our understanding of the world around us.

“For me, it’s fascinating because you would not be able to do this without large molecular datasets. This would have been impossible ten years ago,” says Lumbsch. “It’s another piece to the puzzle to understanding what’s around us in nature.”

“We expect a lot of patterns from studying other organisms, but fungi don’t follow the pattern. Fungi are weird,” says Huang. “They’re really unpredictable, really diverse, really fun.”

This study was contributed to by researchers from the Field Museum, Kasetsart University, Brigham Young University, and Academia Sinica.

Mysterious Indian lichen discovery in Dutch Biesbosch?


Chaenotheca biesboschii (photo: Bart Horvers)

Dutch Vroege Vogels radio reported on 31 May 2019 that a lichen species, new to science, had been found.

It was discovered in 2016 on willow wood in the Biesbosch national park. After much research, it turned out to be a new species. It was called Chaenotheca biesboschii, after the place where it was found.

They are small, making them inconspicuous. More research found out that they are not rare in the Biesbosch.

We don’t know where the species came from. The very small spores of this lichen genus probably can travel over long distances. Maybe it is from a country where some lichen species are still unknown. Chaenotheca gracillima from India (which also occurs, rarely, in the Biersbosch) is a close relative. So, maybe, the spores of Chaenotheca biesboschii traveled all the way from India to the Netherlands.

Save rare lichens in Dutch Gelderland province


This 1 November 2016 Dutch video from Gelderland province ia about Thijs van Trigt who tries to save rare lichens on the dike south of the lake separating Gelderland province from Flevoland province.

Translated from Dutch Vroege Vogels radio, 4 January 2019:

It is quite a job that Thijs van Trigt has started: cleaning a piece of dike between Nijkerk and Putten. And all to preserve the rare lichens that grow on the stones.

Xanthoparmelia protomatrae and Brianaria lutulata

The lichens are now overgrown by plants and mosses. And that while some types of lichens only occur in Nijkerk, such as Xanthoparmelia protomatrae and Brianaria lutulata, Pertusaria lactea, Anaptychia runcinata and Pertusaria aspergilla are also extremely rare and have been found on the dikes near Nijkerk.

Lichen reserve

Thijs van Trigt has been visiting Nijkerk regularly since the discovery of the lichens on the dike in 2015 to clean a piece of dike. But getting rid of the vegetation is a big job. The cleaning action must actually have a periodical character if the effect is to be permanent.

It is therefore the wish of Thijs van Trigt to design parts of the dike as a lichen reserve, with a permanent information sign with explanations for the interested passers-by. By making a reservation, Thijs van Trigt hopes for a better protection of the lichens.

California wildfires kill lichen


This 2013 video from the USA says about itself:

Lichen Identification Methods

From the field to the lab, we take a brief look at how lichens are identified by sight and by chemical spot tests. This video was made for a Lichenology class at Oregon State University by Jena Fay and Sara Lynch. Lichens mentioned here include Cladonia, Lobaria, Evernia, Usnea, Ramalina, Xanthoria and Bryoria. Happy identifying!

From the University of California – Davis in the USA:

Lichen is losing to wildfire, years after flames are gone

Wildfire is reshaping forests and lichen communities

August 9, 2018

As increasingly hot and severe wildfires scorch the West, some lichen communities integral to conifer forests aren’t returning, even years after the flames have been extinguished, according to a study from scientists at the University of California, Davis.

Lichen, an often overlooked organism that forms fuzzy, leaf-like layers over tree bark and rocks, is an unsung hero in forest ecosystems. It provides food for deer, caribou, and elk and is sometimes the only food source for flying squirrels, which are key prey for threatened spotted owls. Birds and insects use it to eat and nest. An important contributor to the nutrient cycle, it also helps fix nitrogen in forest soils.

“Lichen are beautiful, ecologically important, are all around us and tell us important things about the environment”, said lead author Jesse Miller, a postdoctoral scholar in the Department of Environmental Science and Policy at UC Davis. “But even if you don’t notice lichens, you would notice the consequences in ecosystems when they are lost.”

LICHEN LOSS AND FIRE SEVERITY

For the study, published August 9 in the journal Global Change Biology, researchers sampled lichen communities in about 100 study plots across California’s Sierra Nevada region. Five wildfires had burned, at varying levels of severity, in and around the plots between four and 16 years before the study’s sampling.

The results show that lichen communities were largely unaffected by low-severity fires. This suggests that prescribed fires and natural wildfires under moderate weather and fuels conditions are compatible with lichen diversity.

But areas that experienced higher severity wildfires had significantly lower abundance and diversity of lichen.

In severely burned areas where most of the trees died, nearly all the lichen were gone, even 16 years after the fire.

RECOVERY RACE

The lichens‘ recovery is likely held back by the loss of tree canopy after the fire, the researchers said. The hot, dry microclimate left in the forest post-fire is not conducive to lichen growth. This indicates that lichen communities burned in Sierra Nevada forests likely won’t recolonize until mature trees regrow and the forest canopy is restored. This may exacerbate the effects of climate change that already threaten lichens.

“If the species could keep pace with the rate of climate change, the effects of fire might not be so bad”, Miller said. “But the concern is they might not. These fires happen so quickly and in such a large area, they could cause species ranges to contract faster than they are expanding.”

The study also indicates that the trend of increasingly dry forests and hotter, bigger and more severe wildfires could cause broad impacts to lichen diversity across the landscape, which could impact nutrient cycling and multiple food-chain interactions among wildlife.

The study areas included:

Yosemite, in areas burned by the Rim (2013) and Grouse (2009) fires

– Greater Lake Tahoe Basin, in areas burned by the Showers (2002) and Long (2009) fires

– Warner Mountains, in northeastern California, in areas burned by the Blue Fire (2001).

The study’s co-authors are Hugh Safford of UC Davis and the USDA Forest Service, Pacific Southwest Region; and Heather Root from Weber State University in Utah.

The research was funded by the USDA Forest Service, Pacific Southwest Region.

Prisoners paid $2 a day to battle California’s deadly wildfires. US activists say the scheme is ‘inhumane’ and exploitative: here.

Firefighter casualties mount from California wildfires: here.

The West Coast of the United States is shrouded in smoke from the 110 large fires (this does not include smaller fires within each complex of fires) that have erupted across the region during this fire season: here.

Over 3,000 lichens in Alps mountains


This 2014 video is called Lichen Biology.

From ScienceDaily:

The Alps are home to more than 3,000 lichens

March 12, 2018

Summary: Widely used as biomonitors of air quality, forest health and climate change, lichens play a vital role. However, no overview of their diversity across the emblematic Alps had been provided up until recently, when an international team of lichenologists concluded their 15-year study. Their annotated checklist includes more than 3,000 lichens and presents a long-missed benchmark for scientists studying mountain systems around the globe.

Historically, the Alps have always played an emblematic role, being one of the largest continuous natural areas in Europe. With its numerous habitats, the mountain system is easily one of the richest biodiversity hotspots in Europe.

Lichens are curious organisms comprising a stable symbiosis between a fungus and one or more photosynthetic organisms, for example green algae and/or cyanobacteria. Once the symbiosis is established, the new composite organism starts to function as a whole new one, which can now convert sunlight into essential nutrients and resist ultraviolet light at the same time.

Being able to grow on a wide range of surfaces — from tree bark to soil and rock, lichens are extremely useful as biomonitors of air quality, forest health and climate change.

Nevertheless, while the Alps are one of the best studied parts of the world in terms of their biogeography, no overview of the Alpine lichens had been provided up until recently, when an international team of lichenologists, led by Prof. Pier Luigi Nimis, University of Trieste, Italy, concluded their 15-year study with a publication in the open access journal MycoKeys.

The scientists’ joint efforts produced the first ever checklist to provide a complete critical catalogue of all lichens hitherto reported from the Alps. It comprises a total of 3,138 entries, based on data collected from eight countries — Austria, France, Germany, Italy, Liechtenstein, Monaco, Slovenia and Switzerland. In their research paper, the authors have also included notes on the lichens’ ecology and taxonomy.

They point out that such catalogue has been missing for far too long, hampering research all over the world. The scientists point out that this has been “particularly annoying,” since the data from the Alps could have been extremely useful for comparisons between mountainous lichen populations from around the globe. It turns out that many lichens originally described from the Alps have been later identified in other parts of the world.

“It was a long and painstaking work, which lasted almost 15 years, revealing a surprisingly high number of yet to be resolved taxonomic problems that will hopefully trigger further research in the coming years,” say the authors.

“We think that the best criterion to judge whether a checklist has accomplished its task for the scientific community is the speed of it becoming outdated,” they conclude paradoxically.

The new checklist is expected to serve as a valuable tool for retrieving and accessing the enormous amount of information on the lichens of the Alps that has accumulated over centuries of research. It offers a basis for specimen revisions, critical re-appraisal of poorly-known species and further exploration of under-explored areas. Thus, it could become a catalyst for new, more intensive investigations and turn into a benchmark for comparisons between mountains systems worldwide.

Lichens, what are they?


This video says about itself:

25 January 2018

For 150 years, scientists believed lichens were defined by a symbiotic relationship between a fungus and algae. Meet the team of researchers who upended this belief in this short film by Andy Johnson, Talia Yuki Moore, Chris A. Johns, and Kate Furby.