Hello. My name is Linda Geiser, I'm an ecologist for the U.S. Forest Service and over the past 30
years one of my jobs has been to track air quality and climate using lichens as bio-monitors. Today
we're going to be going to a variety of sites to see how air pollution impacts lichens, how it
changes the species that we find there, and how it affects the ecological roles that they play.
So we're standing here in a Douglas Fir forest at the west end of the Columbia
River Gorge. We're only 10 or 20 miles away from the Portland-Vancouver metropolis.
So we can see some signs of air pollution and the lichens here. Some of the things that you
see here look kind of scruffy and crusty. Those are Crustos Lichens. There's a greenish one here.
There's some white ones here that look like paint. The ones that we focus on for air pollution
indicators are the larger the macro lichens which tend to be leafy or shrubby and we have four or
five species of macro lichens to look at here. And the thing I'll point out first is that everything
that we're looking at is an air pollution tolerant lichen. There are no sensitive species here.
So that's the first tip off that there's could be an air pollution problem here.
So honing in on this first one, one of the Grey Rosette Lichens,
you can see right here in the middle there's an area that's faded and bleached and reddened and
that's where the algae have been killed and this part of the lichen is dying.
If you go up the tree a little bit, way up here, we see another lichen and this is a Punctilia.
There's a big patch of it here, and again there are very distinct patches that are damaged.
You can see how they're red and bleached looking where the algal layer is completely destroyed.
But, this part of the lichen is still healthy and there's another big necrotic spot here
and this is kind of normal that the damage is not even across the tree. But you see patches.
From my experience, this is an effect of acid rain where the algae are very sensitive to acidity.
So we're here in the eastern part of the Columbia River Gorge Scenic Area, where the climate is much
drier than some of the other sites we visited. And as a result we have a different lichen community
here. Lichens that prefer a sunnier, warmer, drier environment and one of the key lichens that
we're noticing is this one here which is called Evernia, or the Perfume Lichen. The other thing
we're seeing here are lichens that are responding to air pollution. Lichens that are here because
there's excess nutrients in the environment that's deposited from fertilizing air pollutants,
like ammonia and nitrates. The telltale sign of that is the presence of these yellow lichens here.
These bright yellow lichens are lichens that require more nutrients than you would
normally find at a clean air site and they're thriving here. There's quite a lot of them.
There are also some more cryptic lichens that are responding to nitrogen as well.
Another sign that these lichens are under stress is the condition of the lichens that
are supposed to be here because of the climate, but are not doing well
because of the extra stress from pollution. And so, if you look at this lichen here is some of
the Evernia in very poor condition. And there's also more of it here that's in poor condition.
So, here I've posed healthy lichens on a branch stuck here next to lichens that are
under stress. We're looking at three different lichens that are normal here for this climate.
The Perfume Lichen, the Shield Lichen here, and this Tube Lichen. And on the contrasting branch,
which is in poor health, where the lichens are in poor health, we're seeing
some of the same species. For example this Perfume Lichen, this brownish lichen here
but in very bad condition. We also have some of the pollution indicator lichen showing up here.
This yellow lichen, and the white lichen, next to it, which are an indication of nutrients and
fertilizing pollutants in the air. Here on this branch we have a really nice example
of species that are responding to nitrogen fertilizing pollutants. We have the yellow lichen,
this white lichen here, and this red alga, the free living alga. And the three of them together
are indicating that there's loads of nitrogen at this site that's being deposited to this
tree from the air. The three of them tell you, without making the measurement,
that there's plenty of nitrogen at this site. So you can read the air quality from a tree branch
We're in the Gifford Pinchot National Forest now, in Washington, in a place with clean air.
And you can tell that because of the kind of lichens that are here. Take a look at these
long bearded lichens in front of you hanging from this tree in the forest.
These lichens are very important in the ecosystem in this forest.
They're used by many different types of wildlife. They're used by birds as nesting material,
deer love to eat them in the winter time. The deer and other ungulates really prefer these
and they can be a bridge or survival food in the winter time for these animals. Other animals like
flying squirrels and voles can rely pretty much solely on lichens in the winter time. The fact
that they're here is an indicator in itself that the air quality is very good because these are
among the most sensitive lichens to air pollution. But what tells you even more, is that they're very
abundant here. There's large amounts of it and not only this lichen but many other sensitive
lichens. Just by looking at the trees you can tell a lot about the air quality at this site.
Now we're looking at a branch lower down in the canopy and we're seeing some more evidence of
good air quality. And what we're looking at right now, it looks a bit like an oak leaf,
but, this is actually something called lung lichen. And the lung lichens are different than
most other lichens because their photo partner is a blue-green bacteria instead of a green algae
and that makes them different physiologically. They have much higher requirements for moisture
which is why you're finding them lower down in the canopy, where it's not so dry as it is at the top.
They are also very sensitive to air pollution and when you see them, and again, in such abundance,
and so large, and so many different kinds you have a sure sign that the air quality here is really
good. And that's a very comforting thought because air pollution is harmful not just to lichens but
to to many other organisms in the forest to trees to other plants. If you see that the lichens are
in good shape, and you have sensitive lichens, then you have some confidence that
other air pollution sensitive plants are also doing fine. So let's look at some more of the
cyano-lichens, the lichens that have a green a blue-green bacteria as their photo partner
that are here. These ultra air pollution sensitive lichens. We have something here called a Peltidra,
which is kind of dark underneath. It'll have some, it'll have veins. And then here we have what's
known as the kidney lichen and you're looking at these little brownish orangish discs which are
the fruiting bodies of this lichen. Those fruiting bodies will release spores that will combine with
blue-green pre-living blue-green bacteria and start a whole new lichen. And yet here's another
kidney lichen without the fruiting body. So obviously, so here we have one, two, three,
four, and here's even a fifth Cyano Lichen all growing within a few inches of each other.
This diversity, the size, the abundance
of these highly sensitive lichens is a very good indicator that the air is clean here.
We're here on top of Larch Mountain in the west end of the Columbia River Gorge at about 4 000
feet. We're in a Noble Fir Forest. It's a second growth forest, you can see the
remnants of the old growth forest right next to me or at least one of them. And,
we're looking at what we can learn from the lichens here
and one thing you might notice right away is that there are no orange lichens, no yellow lichens,
none of the little gray Rosette Lichens. So that means we don't have a problem with fertilizing
air pollutants here. On the other hand, we do have lichens that represent a variety of sensitivities
to air quality. So, we have some tolerant species like this Hypogymnia they're tube-like and this
Hypogymnia Physotes and we have a little bit of the shield lichen here as well which I'm going to
take a look at like right there. But we also have more sensitive lichens that we didn't see earlier
like the Platysma Glauca here, the Tattered Rag Lichen, and its cousin the Norwegian Tattered
Rag and then we also have Flatismicia Stenophila here. So, we have quite a few different species
so overall what we're seeing is healthy growth of lichens. We're not seeing that it's limited
only to tolerant species. We're seeing a variety of sensitivities among the lichens
that are here and we're seeing a little bit of a beard lichen. So, we can put this at the cleaner
end of the air quality gradient compared to a couple of other sites that we've been to here.