Tuesday, December 13, 2016

A lichen to look for

In the 1830's, a man named Thomas Lea collected a river bottomland lichen in a "bog" near Cincinnati, Ohio.  This lichen was named Phaeophyscia leana after the first collector, and few people have seen this lichen since its first discovery.  This lichen grows in a particular habitat, one not known for lichen diversity.  It grows in floodplains of large rivers, specifically where the spring waters rise and stay for days on end.  Most lichens can not live in this habitat due to the amount of time under water, but this is exactly where Phaeophyscia leana, or commonly known as Lea's bog lichen, is found.
Lea's bog lichen, Phaeophyscia leana.  When dry appears grey in color with narrow lobes.  May have apothecia (dark discs)
Few other locations of Lea's bog lichen was known in the early 1900's and by the 1960's, this lichen was considered extinct.  The Cincinnati population was gone and no other populations were known.  20 years later the lichen was re-discovered in Illinois.  In the 1990's surveys were conducted along the Ohio and Wabash rivers and small populations were found in the floodwater areas of Illinois, Indiana, Kentucky and Tennessee.  But these are small populations in such a limited habitat.

Word got around that this lichen was being found again in river bottomlands of states bordering the Ohio River, but what about Ohio?  In the early 2000's, a great botanist named Dan Boone spread the word our way about the potential of this lichen being found in flooded areas of southern Ohio.  He knew that the preserve started inventory of its lichen diversity, and a local naturalist named Barb Lund was actively collecting lichens in Adams County.  She went to an area of the Ohio River that appears to flood annually and easily found a lichen growing on tree trunks under the water mark of high water.    She brought me the lichen since she knew I had started identifying lichens and although I think she already knew what it was, we ran chemical tests on it and ran it through the keys.  Sure enough, this lichen was Phaeophyscia leana.

Often growing amongst the mosses on the tree trunks, Phaeophyscia  leana will look most like a Physcia, but larger.
Soon after, I checked areas of the preserve that were susceptible to flood waters and quickly found 3 separate areas of the preserve with populations of Phaeophyscia leana.  It was just a matter of knowing where to look, and what to look for.  As of now, these are the only known populations in Ohio of this lichen, but I know it is elsewhere.
Lea's bog lichen habitat.  This area along Ohio Brush Creek near the Ohio River holds 6 feet of water during floods.
It has been a few years since I have found this lichen in a new spot on the preserve, so this year I was excited to hear about a new property the preserve was buying near the Ohio River.  A new addition to the preserve called Smokey Hollow is protecting almost 1000 acres of new land.  I visited this tract with Rich McCarty this week specifically to find Lea's bog lichen because the habitat looked perfect.  After a short time of searching, we came across a patch of ash trees that contained numerous rosettes of this state endangered lichen.  I saw at least 45 trees wearing this lichen, mostly Fraxinus sp. (ash), a Acer Segundo (box elder) and some  Acer saccharinum  (silver maple).

Lea's bog lichen on ash tree in Smokey Hollow, a new location for an extremely rare lichen.
Unlike other Phaeophyscia's, Lea's bog lichen is white on the undersurface instead of black.  Greenish when wet.
I believe that a survey of the Ohio River bottomlands will produce more populations of this lichen.  But imagine how fragile this habitat could be.  Since these lichens are one of the few to survive under water for days, maybe weeks, they are definitely susceptible to un-natural chemicals added to our waterways.  Unfortunately, the majority of trees we found Lea's bog lichen on were ash trees.  In our area, the Emerald Ash Borer is probably going to kill most of the ash trees in these flood plains.  In fact, many of them we saw were stressed already because of this beetle.  No doubt in 5 years most of these ash trees will be gone, along with the lichens growing on them.  Because of these threats, and the fact that its habitat is so restricted, there has been talk of listing this species as a federally endangered species.
Even silver maples on the edge of the Ohio River could have Lea's bog lichen growing on them, which some of these do!
No matter what it's listing, better knowledge of this lichen's range should be known.  If you find yourself in the right habitat, and you see a lichen on the trunk of a tree where a river obviously floods, take a picture.  This species can be identified by a photo, especially if the habitat is true annual floodplain and no other lichens are found nearby.  If you take a picture of something you think is Lea's bog lichen, send it to me at mzloba@cincymuseum.org.

Posted by: Mark Zloba