Lichens on frontline of air quality research in Colombia

In the herbarium of Bogotá’s Universidad Distrital, lichenologist Dr.Bibiana Moncada opens a red envelope to reveal a leafy lichen that happens to incorporate her name – Sticta viviana.

“This specimen is the holotype,” she said, revealing a weave of lettuce-like fronds. As the first specimen of a species to be collected and identified, the researcher has subsequently classified dozens, many found just a short distance from Bogotá.

One of the many thrills of being a “lichen expert” is having a species named after you, though with modesty typical of those in the scientific community, Moncada had hers proposed by peers – just as in turn – she has put her own mentors’ monikers to her own discoveries.

The Distrital’s herbarium houses 20,000 samples from hundreds of species, but it is the tray of red envelopes – the “holotypes” – that I watch. “This is numero uno, the first known to humankind,” I say to myself.

It was a similar awe that first drew Moncada to the world of lichens as a student in the 1990s at the Universidad Nacional. “When I looked closely at lichens, they were fascinating and beautiful, but also so unknown.”

Part of their mysterious beauty lies in the fact that while recognized as organisms and identified by species, lichens are actually a collaboration of fungi, algae and nitrogen-fixing bacteria. These three classes of simple life somewhere down the genetic timeline decided “together we’re better” and formed mini-ecosystems. Even though lichens look superficially like moss, they are not considered plants.

“Lichens are fungi that learned to farm,” explains Moncada, of a genus that cannot photosynthesise, so it relies on sucking up nutrients, which limits its scope of habitats. We have probably walked past a million lichens and never given them a second glance. But get close up and you’ll be amazed, like the first time you snorkel over a coral reef.

On a walk in the Cerros Orientales of Bogotá I take a magnifying glass and I am soon enraptured by the myriad of colours and forms that lichens take: from gun-metal grey lettuce-like leaves, to miniature forests of bulbous stalks, orange crusts coating rocks, or the old-man’s-beard laments coating the tree branches and making the woods appear magical. All the time thinking: How did little critters ever first get together to make all this?

It is a question that mentally pitches us into the primordial soup, like cosmology, and leaves us pondering life, the universe, everything. It also perhaps explains the almost religious passion that scientists share for lichens (a biologist friend in London throws his hands in the air and shouted “Hallelujah” when I casually mention the “L” word) and some of the extreme lengths taken to study them. Such as sticking lichens to the outside of the International Space Station for 18-months to see how they get on in a pure vacuum with extreme heat, cold, and ultraviolet and cosmic radiation. They not only survive, but come back to earth to keep on growing.

Not surprisingly, on terra firma lichens have evolved to live in the cold arctic, hottest deserts and everywhere in between. Some individual specimens are over 10,000 years old.

Paradoxically, these extremophiles can also be highly sensitive to chemical pollution from car fumes. “Lichens lack the waxy coating that protects plant leaves, so any airborne pollutants are quickly absorbed by the chlorophyll at cellular level,” explains Moncada. This means they make excellent bio-indicators of air contamination, and a growing strand of research that is correlating lichen colonisation with traffic and air quality data in Bogotá and Medellín.

According to the scientist, one can also use lichens to find the perfect home. “When you decide where to live in a city, look for lichens. The more there are, and healthier they are, the better quality of life.”

Beyond the city’s limits lichens thrive best and form an important part of ecosystems, invading just about any natural surface, including old trees, which they help rejuvenate by trapping water in their spongy bodies and fixing nitrogen levels.

They are also a food source for animals and have been used throughout history by humans to dye clothes. In traditional medicine, the natural antibiotic properties of lichen have been long recognized. The wispy Usnea is an excellent wound dressing, as one example.

“The use of lichens by the indigenous people of Colombia has yet to be properly studied,” claims the researcher. Though, she is aware that until recently, in parts of Boyacá, lichens were used to dye ruanas.

Better understood is how the variation of lichen species can unravel long-term changes in the Colombian environment, such as the rising of the Andes over eons of tectonic change, leaving biological islands of highland paramo with distinct species. This is Moncada’s speciality and one that draws her team to the high-altitude wetlands, surrounding Bogotá, such as Guasca and Sumapaz. The botanists take photographs and collect samples that form the rare collections in both the Distrital and Nacional.

It is this work that is putting Colombia firmly on the world stage in terms of lichenology, and takes Dr Moncada all over Latin America, New Zealand and Hawaii to study them. One of her finds, Lobariella sipmanii (which she named after an influential Dutch lichenologist) was featured in the The Guardian newspaper for its “delicate beauty” and how its discovery, and others similar, represents cross-continental collaboration.

Whereas in times past, taxonomy (naming and classifying of species) was a lonely and tedious task undertaken by individual scholars, the trend now is for experts from across the world to work together and joint-publish scientific papers bringing new species to light. L. sipmanii was first described in a paper with 102 authors from 35 countries. Colombian lichenologists (there are around 20) are firmly plugged into that worldwide network.

Classification of lichens used to rely on the physical characteristics and differences, often seen under a microscope, but nowadays, the process is assisted by molecular DNA tests. But it still takes a good eye to spot an unusual and possibly new species – a knack which Dr Moncada has clearly acquired. After re-examining existing samples in herbariums, she found 40 new species of Sticta lichens, and 25 new types of Lobariella. Of the 18,000 lichens so far found worldwide, 5% are from Colombia and a number that is sure to rise.

Colombian lichenologists focus their studies on the Andes because the páramos are “evolutionary hotspots.” This leaves large swathes of the country relatively unstudied, though that is slowly changing as well, with lichenologists looking at the Chocó, Caribbean and department of Huila. “We estimate that there are 2,000 new species out there,” says Bibiana with a radiant smile. But somehow, I suspect, that is just a beginning as Colombia’s lichen lovers find more.

TIPS: If you want to spot lichens in the Bogotá hills there are some excellent photo field-guides by Dr Bibiana Moncada and her team with the collaboration of the Field Museum in Chigaco. These can be downloaded for free at the http://fieldguides.fieldmuseum.org/ .

Here, you can use the search facility to find:

Lichens of the Colombian Páramo – an overview of lichen commonly found above 3,000 meters in the Andes around Bogotá

Líquenes de las cuencas de los ríos Fucha y Arzobispo, Bogotá D.C. – a more detailed look at specimens found along the rivers Fucha and Arzobisbo that run from the eastern hills into Bogotá.

Líquenes epífitos de Quercus humboldtii – a remarkable collection of photos of the 50 species of lichens that live on the Colombian roble, oak.