Becky Thorp is the Senior Plant Recorder at The New York Botanical Garden.
Flavoparmelia caperata
Do you like to breathe? If yes, then I have excellent news for you: lichens are easier to find in the New York metropolitan area today than they have been for decades, and this is an indicator of improved air quality.
Lichens are composed of a symbiotic relationship between photosynthetic algae or cyanobacteria, which create food from sunlight, and a fungus, which provides shelter. They can be found growing on the surfaces of tree trunks, rocks, lean soil, tombstones, and other surfaces on every continent and in every type of terrestrial ecosystem on earth. Able to withstand extreme variations of moisture and temperature, lichens have even survived long periods in outer space. What they can’t survive is air pollution here on earth, especially in the form of soot or sulfur dioxide, because they absorb nutrients directly from the atmosphere. Given this fact, it comes as no surprise that while they thrived in the New York area in the early 19th century, the number of local lichen species declined sharply in the 20th century with the growth of industry and population.
Stevenson Swanson is the Science Media Manager at The New York Botanical Garden.
Dr. James Lendemer (standing) tells host Stephen J. Dubner (seated, center) and co-hosts A. J. Jacobs (left) and Sas Goldberg (right) something they didn’t know about lichens.
Readers with an interest in economics and listeners to public radio know Stephen J. Dubner as one half of the writing team behind the best-selling 2005 economics-for-everyman book Freakonomics and as the host of the program Freakonomics Radio.
A triple threat, Dubner is also the host of a game show podcast, Tell Me Something I Don’t Know, in which a handful of guests with a particular expertise talk to Dubner and his co-hosts about their subject and then the audience votes for its favorite expert. The prize: the satisfaction of winning and a nice commemorative certificate.
In a recent episode, “Farming without Sun or Soil and Manna from Heaven,” NYBG Assistant Curator James Lendemer, Ph.D., talked about his passion—lichens, combinations of a fungus and an alga that play important roles in ecosystems by filtering water and air and by providing habitat and food for wildlife.
As Dr. Lendemer explains, lichens are so sensitive that they are considered an indicator of air quality, but they are also tough enough to survive in outer space.
To listen to the full episode—and it’s worth listening to the end—head here.
Jessica L. Allen is a graduate student at the Commodore Mathew Perry Graduate Studies Program, and James C. Lendemer, Ph.D., is an Assistant Curator at the Institute of Systematic Botany, both at The New York Botanical Garden. Lichens are their primary research interest.
This composite image shows, on the left, a lichen-covered tree in a healthy forest in the Black Mountains of North Carolina and, on the right, how most trees in New York City look.
Most trees and rocks in New York City look naked, while trees in wilder parts of the United States wear a vibrant, colorful coat. What causes that? It’s because after centuries of changes to the environment, many lichens have been pushed from our urban or suburban landscapes and into the wilderness.
Lichens are fungi that, in addition to forming beautiful mosaics on trees and rocks, are critical to maintaining healthy environments. Unfortunately they are also extremely sensitive to air pollution and disturbance. That is why if you grew up in New York, and many other cities, you might think that bare trees and rocks are normal.
The good news is that, like the oysters that are slowly returning to New York harbor, there are more lichens in New York City now than there were 30 years ago. Yet there are still hundreds of species that were once found in the metropolitan area and are no longer here. We decided to investigate whether or not more lichens could survive in the city if we just gave them a little help getting here.
William R. Buck, Ph.D., is the Mary Flagler Cary Curator of Botany at The New York Botanical Garden. Every January for the last three years, Dr. Buck, a moss specialist, and a team of colleagues have journeyed to the Cape Horn region at the southern tip of South America, to document the area’s rich diversity of mosses and search for new species.
Yesterday our activities were dominated by water. Due to a shortage of fresh water, we could no longer bathe until the tank was refilled, and flushing the toilet was accomplished with a bucket of sea water. We started the day at Bahía Windhond on the south shore of Navarino. I’d never had the opportunity to collect on this side of Navarino, so I was glad to see this prominent bay at last.
You’ll find them clinging to rock faces like flecks of gray paint, or carpeting a tree trunk with skeins of red whisps. Lichens come in myriad shapes, sizes, colors, and consistencies. But while they’re often overlooked during your average hike, they’re worth giving a spare glance the next time you’re outdoors–lichens play an important part in the ecosystem. Few know this so well as the NYBG‘s Dr. James Lendemer. Like many of the Garden’s globetrotting scientists–Michael Balick, Bill Buck, and Roy Halling, to name a few–Lendemer’s field odysseys carry him well beyond the laboratory door in his hunt for specimens. In recent years, that chalks up to long days spent trekking through the Great Smoky Mountains of the eastern United States.
For the uninitiated, lichens are cryptogams–fungi that reproduce by spores, as with other fungi and some groups of plants. But unlike either, lichens are unique in that they’re composite organisms, often a symbiotic combination of fungi and algae. Think of them as codependent roommates; the former acts as a sort of bodyguard for the latter in exchange for nourishing sugars from the algae’s photosynthesis. At large, lichens make the perfect bird nests by some avian standards, and the growths also have a penchant for breaking down dead trees and rocks while providing nitrogen for soil. Unassuming as they are, they’re integral to maintaining healthy biomes.
