Earth & Sky

The following individual(s) were interviewed for today’s show. Our thanks to:

Dawn Kirk, Forest Fisheries Biologist
George Washington & Jefferson National Forest
Natural Bridge Station, VA

The following books, articles and web sites were used in preparing this script:

To learn more about the George Washington and Jefferson National Forests,
please visit their website here.

To learn more about cave ecosystems, visit the University of Texas webpage
“Biospeleology” here.

Also take a look at the article “Caves hold a hidden trove of biodiversity”
on the CNN website here.

To learn more about cave conservation in Virginia, visit the Cave
Conservancy of the Virginias webpage here.

To learn more about caving, visit the National Speleological Society webpage

Author’s Notes:

Interview with Dawn Kirk, Forest Fisheries Biologist George Washington &
Jefferson National Forests

E&S: Can you tell us about the caves?

DK: When we looked at all of the information we had on the caves in the
forest, we had about 80 caves in the forest that we knew of. We don’t have
a lot of limestone on the National Forest, and they’re all different sizes.

E&S: What’s the difference between karst and limestone?

DK: Well, limestone is part of a karst system. A lot of the valleys, like
the Shenandoah Valley, have limestone. And the Forest Service owns a lot of
the mountaintops. So we don’t own a lot of the karst.

E&S: The 80 caves we’re talking about, are they part of the forest?

DK: Yes, they are all National Forest caves.

E&S: And those were the ones that were surveyed?

DK: Yeah

E&S: What’s it like inside those caves? Do many of them have stalagmites
and stalactites, and when you talk about aquatic fauna, where is it found?
In pools and streams in the caves?

DK: The majority of our caves are dry caves but they would have pools, or
might have springs or seeps from the groundwater that comes up during wet
times of the year. Some of them do have streams.

We don’t have any cave fish that we know of. Most of the aquatic life are
insects or amphipods and isopods, that’s what we’re mainly dealing with
here …. [Amphipods and isopods] are a kind of crustacean, related to
crayfish and other small crustaceans. What’s neat is that the ones found
strictly in caves are white and have reduced eyes, or no eyes, and they’re
pretty rare. A lot of them are found in groundwater.

We did not really have a good record of what we had in caves, and a lot of
our caves don’t have water in them so we were setting up the survey to
survey the caves that just had water. When you get into the karst system,
the water that is in the caves is obviously really affected by management
that happens around the caves. If you’re affecting the water resources
around the cave, you’ll be affecting the water inside the cave.

E&S: So you’re saying that the water resources in the cave are a reflection
of the surrounding ecosystem?

DK: Yeah.

What we did was set up this project as a partnership because we don’t have
the people, the time, or the expertise to look for this stuff. So we
utilized volunteers.

E&S: How did you recruit the volunteers?

DK: Well, *Terri (Brown) is in a lot of caving organizations, like the
Virginia Speleological Society and things like that, and she had a network
of interested people. A lot of these cavers are people who actually map
caves for the USGS (U. S. Geological Survey). So they’re real interested
and obviously very expert cavers. But they were not trained in the biology
of the caves.

So we got a grant and we set up a workshop. We had over 25 cavers who came
to the workshop on a weekend. And we brought in some professors who taught
them how to sample and what to look for. Then we divided them into groups
and we sent them off to the caves, and they looked for the amphipods and
isopods and anything in the water. They collected it and sent it back to
the professors. Terri acted as a clearinghouse, so they didn’t necessarily
do the identification but they collected the samples. They really enjoyed
it because they said they don’t look at a cave the same way – even after
all the experience and hours in the caves, they had no ideas there was
stuff in the puddles. Now they’re even more cautious going through caves
because there’s stuff living in the little puddles.

E&S: Did they only sample animal life? Or did they go after any plant life
or bacterial life?

DK: No, not on this [survey]. We got a grant from the Fish and Wildlife
Foundation and that was specifically to look at the aquatic life. And now
that we have this group of volunteers that are all organized and really
interested in all this, Terri and I talked about moving to another group of
organisms which might be bats or spiders, or something like that. But
there’s not a lot of plant life in the caves, unless it’s a fungus or
something like that.

E&S: They only sampled the wet areas ….

DK: Right. And unfortunately, during the year they were doing the
fieldwork, there was a drought. It was 2 years ago, in 1999. It was a
really dry year, so a lot of the caves that may have been wet [during
normal conditions] were pretty dry.

E&S: Out of the 80 caves that you mentioned, what percentage had water in
it that could be sampled?

DK: We prioritized out of 80 [caves] … we prioritized ones that had no
information on them, ones that had no water in them, and ones that had
other aquatic species in them. Probably a third of the caves were known to
have water or some kind of aquatic life in them.

E&S: You mentioned future plans for surveys of other organisms?

DK: Yeah.

E&S: And you’re currently writing grants for that?

DK: One of the people who works with Terri is putting in a proposal for a
workshop on bat identification. But I don’t know if she has the funding for
that.

E&S: Can you tell us more about the biology of the caves? You mentioned
some of the critters so far – what new information have you learnt?

DK: When we were doing the workshop, we went to a cave to train everybody.
It was a cave near a college campus. A lot of people go there and there’s a
lot of trash in it, and a stream goes through it. The professor who was
teaching the workshop said, “all right, just go and see if you can find
anything in there.” And one of the people who dipped their net in pulled up
this large isopod, and the professor looked at it and said, “oh my gosh!
This is an endangered isopod that I’m studying, it’s only known from two
other caves that are hundreds of miles from here.” That one little incident
expanded the range of that species by hundreds of miles. So little is known
about the distribution of these animals that any information is going to be
really adding to the whole body of knowledge.

From the forest standpoint, what is interesting is that we would know that
there is something in particular, like a rare species, in a cave. That
would bump up that cave as far as being a special biological area around
there, and that would affect resources associated with it – from a
management standpoint, it would change things.

E&S: Can you say something about the diversity of the aquatic life?

DK: They are not really diverse. You might find a couple of different types
of animals from one cave. But again, usually these animals are pretty
local. We have some rare cave isopods found in just one cave, or from one
general area. So they may not be very widespread, but very limited to the
places where they are found.

E&S: When you compare aquatic life in various caves, are you then saying
that they’re all very different from one cave to the next? Or are they
similar but slightly different due to isolation?

DK: Yes. It would be more towards the latter.

E&S: I’m trying to understand … what constitutes a species, would you say
each cave has its own species or subspecies?

DK: I don’t know … some of the samples we sent out are still being
identified because there aren’t many people who work on this kind of stuff.
So I don’t even know how they have broken it up. I know some of the isopods
that we call, oh … species #13, or something like that, they really
haven’t been described thoroughly. So I think we know how to break them up
into different species but … at subspecies [level], I don’t know …
there really aren’t a lot of people working on it.

E&S: What’s the lineage of these animals, how long have they been evolving
in the caves?

DK: A lot of them are really just isolated, they’re only known from one or
two locations in a certain area. They probably have been separated for
quite a while so that’s really interesting. And also, this ties in with
cave conservation. People don’t really think when they go into a cave, that
it can really affect the biota in a cave system, even a long ways away. And
the groundwater is being depleted from people pumping it up for agriculture
or drinking water, or it’s being polluted by different chemicals or
something. [Groundwater:] that’s what’s in these caves supporting these
creatures.

E&S: Is chemical analysis of water part of this project?

DK: That was not part of this project, unfortunately.

E&S: You mentioned some of the adaptations these animals had, that they
were white and they have little or no eye pigmentation. Can you describe a
few of them, what they look like?

DK: The amphipods are small, flat, they are shaped like a flea. The isopods
are flat, from the top to the bottom, and their legs go out to the sides,
whereas the anthipod’s legs go straight down. They are pale in color, you
don’t see any eyes.

E&S: How large are they?

DK: You can usually see an adult, up to a centimeter or less [in length].
It really depends on the species.

E&S: Do you know what they’re feeding on?

DK: Anything! Anything they can find. That’s probably the limiting factor
in a lot of these cave systems for these animals. They’re unlike bats that
will go out to forage outside the cave, and use the cave as a place to
hibernate or to rest. For [aquatic] animals that are dependent on the
caves, food is the limiting factor. Anything that’s brought in from the
outside becomes food to them. During our training, what was interesting was
that a lot of times, in order to catch these things, they’d leave a bait
bag out. They’d take a little bag and put some kind of smelly cheese or
something in it, and they’d leave it in the cave and come back within
hours, and everything in the cave has come to that bait bag.

E&S: Did they take water samples to look for microscopic life?

DK: They didn’t. It was what you could see with your eyes.

E&S: The streams and pools, how big or how small are they?

DK: It depends. Some of them are just a small puddle that may be a square
foot, that’s dripping from the groundwater in the ceiling. You can still
get these animals in small puddles because they might be in the
groundwater, and they drip out with the groundwater.

E&S: They actually live in the groundwater?

DK: Yeah.

E&S: They actually live in the aquifers?

DK: Sure. That’s how they can get around from these different systems that
could be associated with that [aquifer]. Quite little is known about that
because how do you [get to them] … unless you can drill a well, but
they’re probably not really abundant. Some of the [cave] streams may be as
large as a regular stream. So it really varies.

- end of interview –

• Terri Brown works for the VA Natural Heritage Program, Department of
  Conservation and Recreation.