Lichen & Oak

When Microorganisms have Macro Implications.

It’s easy to walk over, past, and under lichens without ever noticing them. But in detail, these complex organisms reveal intricate textures of varying hues and sizes. Lichens are comprised of fungi and photosynthetic green or blue-green algae, also known as cyanobacteria, and are found from the poles to the tropics.

They line Earth’s forests, grow on cooled lava formations, and cling to bare rocks. Some 13,000 to 17,000 species are known, but many still await discovery.

Earlier this year, a lichen, which is either very rare or potentially an undescribed species, was found by rare plant botanist Kathryn Beck on Columbia Land Trust property near the Klickitat River watershed. Research to determine its identity is ongoing.

“The unknown still exists, even close to home,” said Beck. In 2010, the Land Trust hired Beck to conduct a vegetation survey of Margerum Ranch, a property conserved in 2008 and located northeast of Lyle, WA. The ranch’s 302 acres bear dramatic rolling hills, old-growth Douglas-fir and ponderosa pine, Oregon white oak woodlands, riparian habitat, and upland prairies with mountain range and river views.

The site has some of the region’s last remaining stands of mature Oregon white oaks (Quercus garryana), or Garry oaks, which offer the only known substrate for rare, slow-growing species of lichens.

Used as food, shelter, and nesting material, lichens in Pacific Northwest forests are critical for squirrels, birds, deer, bats, and invertebrates such as wasps and butterflies. Lichens are ecological indicators, susceptible to changes in air quality. They thrive in regions of high air quality and can be absent from cities due to air pollution. In forest canopies, lichens can moderate humidity and temperature and enrich soil content, allowing neighboring plants to thrive.

Five years ago, Beck trekked the grassy hillsides at Margerum Ranch to document plant diversity and became intrigued with the land’s rich lichen assortment. She plucked a sundry of lichen samples, placing them into a paper sack to tote back to her personal lab for further examination.

That winter, Beck sat down with her dissecting and compound microscopes to examine one species she had found on the bark of a mature Oregon white oak. She recognized the sample as pin lichen, a crustose or crust-like lichen with minute pin-shaped reproductive structures. Unable to key out the species with certainty, she sent the lichen sample, the size of a dime, to a pin lichen specialist. The specimen was determined to be Calicium quercinum, a slow-growing pin lichen found only twice in North America, in Illinois and Oregon, and in forests at least 100 years old.

In 2013, that sample was also examined by Oregon-based lichenologists Daphne Stone and Amanda Hardman, who had previously found what seemed to be the same mysterious pin lichen in another location in the Columbia River Gorge. They thought Beck’s lichen sample was similar to Calicium quercinum but had some differing characteristics.

So, Beck returned to Margerum Ranch in 2015 with the lichenologists on a quest to relocate the species again, not knowing which oak tree in the hundreds of acres it had been collected from in 2010. The three biologists came upon five enormous, deep-furrowed oaks with populations of the elusive pin lichen.

“The samples are either an unknown species, endemic to the Columbia River Gorge, or a known but very rare species found in only two other places in North America,” said Beck.

The next step in determining the identity of the lichen is genetic sequencing, a laboratory procedure for which there is currently no funding. The silver lining, perhaps, is that the discovery has a deeper implication.

“These species of rare lichen speak to the value of preserving ancient oak stands and oak individuals,” said Beck.

Oak woodlands and savannas in Oregon’s Willamette Valley have declined to less than 15 percent of pre-European settlement numbers and oak stands in Washington are also limited. Rife development, wildfire suppression, invasive non-native species, and grazing impacts on soil have devastated many of the region’s remaining oak habitats, along with any organisms depending on them, making oak protection a conservation priority.

The palpable interconnectedness of macro- and microorganisms, like the relationship between lichens and oaks, is a reminder that conserving land is essential to keeping the natural world’s most wondrous, complex, and beautiful examples of symbiosis intact. Columbia Land Trust will continue to conserve lands like that of Margerum Ranch so that unexpected curiosities and discoveries of our region may endure.