Rediscovering the Lowly Lichen across the National Park System
Lichens are the Rodney Dangerfield of the natural world. They just don’t get any respect. Lichenologists likewise don’t garner much recognition for their lifetimes spent poking around the crusty grey stuff on tree trunks. Among others, one intrepid man in California is taking steps to remedy both of those deficiencies.
Nature’s Forest Fertilizer
Lichens are composite organisms formed by the symbiosis of an alga and either a fungus or a cyanobacteria. Most folks know lichens as the fungal variety that forms gray mats on rocks and tree trunks. Model railroad aficionados treasure it as a proxy for shrubbery and other vegetation in miniature landscapes. What few people realize is that the temperate rainforest in Olympic National Park depends on lichens to cycle nitrogen. Lobaria oregana pulls nitrogen from the air high in the forest canopy, which is then released to the soil as pieces of the lichen rain down in a nearly invisible shower of fertilizer. Botanist Bill Denison figured this out in the early 1970s while searching for the primary mechanism of nitrogen cycling in old growth forests of the Pacific Northwest. After sending some graduate students with climbing skills a couple hundred feet into the canopy, he concluded that as much a quarter ton of Lobaria (dry weight!) per acre can thrive in the canopy. He believes Lobaria is the largest single system of nitrogen fixation that’s been discovered in old growth forests.
All-natural air-quality sensors!
On the opposite coast, I spent a rainy June afternoon poking around some ravines in the backcountry of Acadia National Park. Erupting from tree trunks everywhere was the showy Lungwort (Lobaria pulmonaria). Lungwort is a prime indicator of clean air in damp forests across the northeast. This lichen is extremely sensitive to sulfur compounds in the air, thus its demise in many forests is a harbinger of the arrival of foul pollutants from industry downwind. Acid rain and acid fog are a death sentence. I hear it also makes excellent moose food, though not being a moose, I have yet to sample any myself and can’t vouch for that claim. Still, lichens are clearly integral players in ecosystems across the continent and worthy of dedicated research. The National Park Service issued guidelines for studies involving lichens as monitors of air-pollution in 2003, but in many cases inventories of the lichens present and identification of lichen “hot spots” has never been undertaken.
A Man on a Lichen Mission
Enter Kerry Knudsen. Mr. Knudsen is a lichenologist working out of the herbarium at the University of California Riverside and he may be the only lichenologist most of the world has ever heard of thanks to his uniquely inspired naming last year of a newly discovered species. Caloplaca obamae, discovered in Channel Islands National Park and an endemic to the islands, was named after the recently elected President of the United States, Barrack Obama. These days, Mr. Knudsen is in Santa Monica Mountains National Recreation Area reliving the work of another self-taught lichen fancier from a hundred years ago. Herman Hasse, a doctor from Los Angeles, started traipsing through the Santa Monica Mountains in 1895, documenting all the lichens he found. His journals and specimens, deposited at Harvard, are the impetus for Mr. Knudsen to “rediscover” as many of Hasse’s reported species as possible. Given their occupation of unique niches and service as bioindicators, the results could be telling.
Mr. Knudsen says he hasn’t had a chance yet to ponder which species may be prime indicators of pollution or other environmental upheaval in southern California. He’s concerned that pollution and increased fire frequency may have greatly impacted more than a few species on tree bark. As many as 50 bark-dwellers that Dr. Hasse recorded have yet to be rediscovered or have been found to be exceptionally rare today. All the other usual suspects are also causing trouble. “I think grazing, development, and invasive weeds have reduced or extirpated terricolous lichens,” Mr. Knudsen says, referring to lichen communities living on the ground. It’s clear Santa Monica Mountains NRA is losing lichen species before we even had a chance to know them well.
Stop to Smell the Roses (Lichens)
I’m sitting on Buck Hill in Theodore Roosevelt National Park, watching the bison graze in the fields below and the evening sun preparing to fire up Painted Canyon in the distance. With all the beauty and vistas on the typical grand scale of the northern plains, I can’t help but be drawn to the rocks at my feet. There on one chunk of glacier-deposited granite was a full color rendering in miniature of the canyon in front of me, gold and orange lichens filling in for the barren rocks and scoria veins in the badlands. As with every lowly fragment of every ecosystem, this rock and its crusty residents have a story to tell. We need only open our eyes and listen.