LESLIE MCCARTNEY: So today is Monday, November 25, 2019. We’re here at the Rasmuson Library at the University of Alaska in Fairbanks. I’m Leslie McCartney, and I have the pleasure this afternoon of speaking to Dave Swanson, a terrestrial ecologist with the National Park Service here in Fairbanks. Thanks so much, Dave, for coming in, um, and speaking with us today as part of the Observing Change in two national parks in Alaska project. The Klondike Gold Rush National Historic Park and the Bering Land Bridge National Park are the two parks that we’re looking at in this project. So we really appreciate you coming in and taking the time to be here today, so thank you and welcome. DAVID SWANSON: Well, I’m glad to be here.

LESLIE MCCARTNEY: So let’s start off with just a little bit of biographical information, where you’re from, where you were -- where you were born, and maybe your early, um, education.

DAVID SWANSON: Ok. So I was -- I was born in Illinois and then moved to Minnesota, which is kind of the place that I say I’m from. And uh, and I went to school there and in Colorado. Eventually, I studied geology and soil science and plant ecology, and eventually ended up with a PhD in soil science from the University of Minnesota.

And then, I moved to Alaska in 1989, uh, to be a soil scientist for the what was then called the Soil Conservation Service. And now it’s called the Natural Resource Conservation Service. And I was the -- was the -- the soil scientist in charge of all the soil mapping investigations that were being done in central and northern Alaska at that time.

And so, I did that through the '90’s, and -- and then I moved away to be a plant ecologist with the Forest Service and -- with my family, too. I have a -- I have a wife that moved up here with me originally, and she got a job with the National Park Service actually back then, originally before I did. And while I was working for Soil Conservation, she was working for the Park Service, actually, in Fairbanks. And we had a daughter in the '90’s, then too, and then in the -- in the early 2000’s, we moved to Oregon for about six years, where I worked as a plant ecologist. And we had another daughter just before we moved.

Um, and then in 2008, we moved back to Fairbanks. Couldn’t stay away. And then this time, I got a job with the Park Service, and -- and that’s -- you know, that’s the one that I have now. So I’ve been it just a little over ten years. LESLIE MCCARTNEY: Ok.

DAVID SWANSON: And um, right. My title is ecologist, and I work for the, um -- I work for the -- I work for a group of parks. It’s called the Arctic Inventory & Monitoring Network, which is just a -- it’s just a grouping of five national parks in northern Alaska. There’s -- of which one is the Bering Land Bridge Park, which is the one that this project is -- is about.

And uh, but we -- the Inventory & Monitoring Program has grouped together parks so that we can sort of join resources. You can’t -- we -- you know, each park couldn’t hire scientists, but a group of parks can, basically, or -- you know, and so that’s how we do it. And so, I work -- I work for five parks. And uh --

LESLIE MCCARTNEY: Can you name the five parks? DAVID SWANSON: So they are Bering Land Bridge National Preserve, which is the one that we’re going to be talking about today. LESLIE MCCARTNEY: Um-hm. DAVID SWANSON: And then I work for Cape Krusenstern National Monument, which is -- they’re all in northern and northwestern Alaska. Kobuk Valley National Park, Noatak National Preserve, and Gates of the Arctic National Park and Preserve. So those are all the parks. All very, very great places to work.

LESLIE MCCARTNEY: You’re very fortunate. DAVID SWANSON: Yep, right. I have -- I have the best job in the US Government, just so we get that out of the way right away.

LESLIE MCCARTNEY: Can we just go back to the soils? You were talking about -- DAVID SWANSON: Sure. LESLIE MCCARTNEY: -- mapping the soils in Alaska. Had that never been done before?

DAVID SWANSON: Well, you know, there had been some soil mapping done, but not certainly -- there still are huge areas that have never been mapped. LESLIE MCCARTNEY: Hm. DAVID SWANSON: Not in any detail, at least.

And so, I worked -- back then, I worked on -- there was -- there had been some soil mapping done right around Fairbanks, um, little bit right around Delta Junction, but that was kinda it. And so, we were doing, you know, other places.

And so, I learned a lot about permafrost and -- and vegetation-soil relationships and that sort of thing, working on that job. And so, I did a lot of mapping around -- I mapped a lot of the farms in Delta Junction, and I mapped a lot of the -- I mapped a lot of the Fairbanks area. I mapped some of the military bases.

I mapped some villages that needed, um, you know, we were -- the -- it was -- the purpose of the soil surveys was occasionally agriculture, but frequently other things. You know, like understanding the permafrost for, you know, construction and roads and houses and all that sort of thing. And forestry and just understanding the environment in general.

I did a -- I did -- one soil survey I did, actually, was for Gates of the Arctic National Park way back when, in anticipation of the Ambler Road Project. They wanted to have information on what it would -- what the road would be on.

And it's turned out, now I work for the park while that -- while we’re evaluating the -- that project. And so, it’s -- it was good that we did it back in the '90’s when we did it.

LESLIE MCCARTNEY: So when you say soil mapping, are you designating, like, a number or a name to a type of soil that you -- DAVID SWANSON: Yeah. LESLIE MCCARTNEY: Yeah. Ok.

DAVID SWANSON: And -- and you gather data about the soils, and then you come up with these descriptions, and you give them names. And then you end up with a map that people can say, ok, this soil has permafrost, and it’s wet, or it’s got lots of soft organic matter on top." And, you know, those kind of things. Or no, this soil is gravelly, and it’s well-drained, and, you know, and that sort of thing.

LESLIE MCCARTNEY: Right. Ok, excellent. So what made you then turn to plants? Did this interest in soils and science led to the plant interest? DAVID SWANSON: Yeah well, you know, I’d always been interested. You know, the reason I got interested in soils originally was mostly because I really could never really settle on one thing that I really wanted to be interested in, right?

So I -- I was really interested in geology, I was interested in plants, and I was interested in soils. And they all kind of work together.

And so, the soil mapping was a good way to be able to dabble in everything at once, you know. And so, that’s something that I -- I still -- I still really enjoy.

LESLIE MCCARTNEY: Right. So let’s talk about, then, this new -- this organization, the five parks, that you’re involved in. What kind of work are you doing with the five parks, then? DAVID SWANSON: So the Inventory & Monitoring Program of the Park Service. LESLIE MCCARTNEY: Yes.

DAVID SWANSON: Each network has a -- they have developed by sort of a public process what they’re going to monitor, and there are things that they call vital signs, which are indicating the, you know, I think the analogy is with the vital signs of a person, like your pulse and your breathing, right?

So we’re -- so we’ve identified vital signs for the -- for our network. And it wasn’t just us. It was -- we tried to, you know, it was -- actually, it was done before I started the job, but a bunch of important environmental features have been chosen as vital signs for every network in the country, not just the arctic network. But the one I work for is called the Arctic Network.

And, you know, as you might expect, there’s a bunch of wildlife ones, like caribou and Dall sheep and that sort of thing. And those are -- I actually don’t work on those.

I work on all of the, sort of the habitat and land-related ones. So I do permafrost, and I do vegetation, and I do coastal change, coastal erosion, and I do, um -- we have another vital sign that’s kind of more generally landscape change, which kind of encompasses a lot of things.

And, you know, like vegetation and some other things. Like we, like one thing we’ll probably talk about here is that as a part of the landscape change vital sign, we monitor changes in the amount of -- in the area of lakes and ponds that we have. And um, so that’s one of the parts of the landscape vital signs.

So anyway, I have four vital signs that I work on, and that gives me the opportunity to, you know, indulge my interest in a wide variety of things, from -- ranging all the way from, you know, from the geology and the soils through the permafrost and the plants, and even a little bit the -- the wildlife, although that’s mostly other people’s, um, job.

LESLIE MCCARTNEY: So how do you make all these observations, then? Um, is it just going out and looking, repeated year after year, or is there -- is it every five years? What’s the methodology used?

DAVID SWANSON: Well, we have -- we -- we combine, um, some monitoring in place, you know, in -- on -- at various stations or plots that are permanently marked.

We combine that with also with, uh, remote sensing, which is satellite observations and aerial photographs and that sort of thing. So we kind of -- we kind of do both.

And the, um -- (clears throat) -- excuse me, the um, for example, we have a -- we have a network of weather mon -- you know, climate monitoring stations, which I don’t work on directly, although I use the data quite a bit. And I -- of course, my office is next door to the person who maintains them. And um, so that’s an example of how we monitor in place.

And then I -- and like, our vegetation monitoring program involves permanently marked, um, places that we go back to and make the same measurements of trees, if there are any, or in the Arctic Network, there really aren’t very many. Like, in Bering Land Bridge there are none. LESLIE MCCARTNEY: Yes. Yeah.

DAVID SWANSON: But we measure the -- we can measure, then, the other -- other kinds of vegetation that are on the site. And those are intended to be returned to.

And so, we have a variety of permanent plots like that that we return to on a -- on a, you know, kind of a rotating basis.

Um, but, you know, that’s -- and, of course, that’s really interesting, and it’s fun to go out in the field, and it really -- you really need to do it so that you understand what’s going on. But then, that’s also -- it’s expensive, and you only learn about a small area because that’s all you can cover when you’re in the field, right?

And so, that’s why -- that’s where the remote sensing comes into play. And so, we do a lot of work with, um, you know, with satellite images and aerial photographs to try to understand the changes, too.

LESLIE MCCARTNEY: And what are some of the earlier -- what’s some of the earliest data points that you have? Like, how -- how long has this research been going on?

DAVID SWANSON: Well, the -- most of the -- most of the plot-type observations, I established, um, in -- there were some that were established prior to mine, but mostly the people that went before me didn’t mark them permanently, and so, um, so that’s kind of what we did was --

So about ten years ago is when we really -- when most -- there were some permanent plots that were set up that we’ve been able to find prior. But most of them, actually, we’ve set up in the last ten years or so. And uh, but then the remote sensing record goes back farther. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And so, we have, um -- the earliest aerial photographs actually go back to the -- about 1950. Most of those are in black and white, though, so that you -- but you can still see quite a few things on those.

And then, starting in the '80’s, we had color and color infrared photographs, and then we started to have satellite images from then, too. And so then -- and the satellite image record has been getting better since then as more satellites have gone up, and the technology has been improved. And so, it kind of gets more and more as time goes on.

And so, since the year 2000, we have a lot of -- a lot of data. And we have enough from the '80’s to really make some interesting observations, but um, it’s certainly gotten better since about the year 2000.

LESLIE MCCARTNEY: Right. So have you -- can you talk about some of the large changes that you’ve seen from there?

DAVID SWANSON: Well, uh, yeah. You know, the -- probably the most dramatic change that we’ve seen in recent years has been this -- has been the sudden drainage of lakes. And that’s one that’s particularly affected Bering Land Bridge.

There’s a lot of subtle changes, too, which we can talk about later. But the drain -- the dramatic -- the most dramatic one that we’ve noticed lately, anyway, was this sudden drainage of lakes.

And the way that works is in, you know, in permafrost regions, um, there’s a lot of lakes. You know, permafrost, particularly where the topography’s flat, um, there’s a lot of water around ’cause it’s basically perched on top of the permafrost, right?

And another thing that happens in permafrost regions is that in, particularly in areas of flat topography, you -- there’s a lot of ice in the ground. And where that ice is built -- built up, it actually -- the ground surface is actually a little higher, thanks to that ice being in the ground.

But then, you -- as you can imagine, ice can melt. And where it melts, you end up with a depression.

And so, these permafrost landscapes end up with -- with, you know, hundreds, thousands of lakes and ponds that are due to local permafrost -- local permafrost thaw.

And the northern part of Bering Land Bridge is just -- just -- you know, there’s places where, you know, close, you know, maybe not quite a quarter of the landscape, at least, you know, maybe ten, twenty percent of the landscape is water, um, because of this permafrost thaw.

And the thing about those lakes is they tend to be shallow, and they also -- they -- their -- their existence is a bit tenuous, because they -- they really only manage to exist because the ground around them is frozen, right?

And ’cause if the ground -- if the ground around them were to thaw, and that would allow it to subside, and the water can run out of the lake. And -- and that is, um, that’s something that happens naturally and always has.

You know, you can look around -- you can look at a photograph of the northern part of Bering Land Bridge Preserve, and you can see the outlines of lakes that have drained in the past. But it seems to be occurring at a really unprecedented rate, um, you know, in the last few years.

Um, and, you know, there’s a couple of things probably in play. One of them is, of course, that it’s been the warmest -- it’s just been -- the last few years have been just remarkably warm. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And we’re breaking records all the time, warmth records. So that means that some of this ice in the ground is melting and providing new paths for the water to get out.

And the other thing that’s been going on is, we’ve gotten a tremendous amount of snow in the last few years in this part of the world, and in, you know, in the Bering Land Bridge area.

Uh, and that means that there’s -- the lakes are kind of brim full, and if the water can find a way out, well then, flowing water enhances the thaw of the permafrost, and so you have that combined with warmth, and it’s really sort of the perfect storm for having lake drainages occur.

And um, so in -- in the summer of 2018 in the northern part of Bering Land Bridge, we -- we lost three, um, three lakes that are -- that were about a mile in diameter.

The lakes tend to be kind of circular in that, um, in that part of the -- in that setting. And we lost three big -- three big lakes that year, and lots of, you know, lots of smaller ones, too.

And then, 20 -- and then in 2019, um, in the same part of northern Bering Land Bridge, we lost another lake about a mile across, uh, and one about a half-mile across, and then lots of -- lots more small ones.

And so, in this one corner of the park where we, you know -- and there have been some lakes that have been lost earlier, too, you know. And some of that’s a natural process, although I think even prior to 2018 it was probably occurring a little faster than it should’ve been.

And if you add up the lakes that we lost in the -- we had a kind of a spell of lake losses in the mid-2000 decade during some real warm weather that occurred back then, um, and you add those together, and there’s one corner of the park where we’ve probably lost about half of the lakes, at least the big ones, that were there before.

LESLIE MCCARTNEY: And once they’re gone, once they’ve drained out, and even if it gets cold again and the -- permafrost reforms, will lakes form there again? Or is there new trenches now that have been --

DAVID SWANSON: Yeah, you know, they -- what usually happens when a lake drains is there’s usually a couple of low spots that stay as shallow ponds. But, you know, a lake, they usually don’t refill.

You know, I mean, there’s -- I think there’ve probably been cases where, like, a beaver dam might -- the beavers might plug up the outlet, and the lake would refill. But, you know, I think I’ve observed that -- I’ve observed that, I guess, once in the Kobuk park, the Kobuk National Park. But, you know, generally, it’s -- once it’s done, it’s done. LESLIE MCCARTNEY: Done.

DAVID SWANSON: And under a -- under a kind of a natural scenario, a pre-climate change scenario, what would happen was, um, small ponds are gradually enlarging by the same process. They just don’t enlarge so much that they make a new outlet, you know.

And so, there would be this kind of, you know, potentially a maybe more of a balance between the processes, right, where you may drain -- you may drain a lake at some point, but, meanwhile, some of these ponds are growing, and you kind of end up with, you know -- we envision anyway, potentially a sort of an equilibrium situation.

I don’t know if that’s -- if that’s -- you know, in nature there are -- there are probably fewer equilibrium situations than we’d like to think. You know, they -- probably things tend to be more episodic than -- than equilibrium in a lot of ways. But, in any case, yeah, the short answer is that those lakes are gone, and that’s that. You know, they’re -- they’re not refilling.

LESLIE MCCARTNEY: And that’s a huge thing for migratory birds, I would imagine. DAVID SWANSON: Right, that’s -- LESLIE MCCARTNEY: They probably use this -- DAVID SWANSON: Right. LESLIE MCCARTNEY: -- these lakes, these long runways?

DAVID SWANSON: Yeah, that’s our -- that’s one of our -- that’s our biggest concern at the moment. They -- they’re shallow, and they don’t have a lot of fish in them, and so I think that they -- the local residents actually haven’t --

you know, if this were happening to, like the lagoons, for example, where they do a lot of their subsistence, then it would just be, you know, they would really be, you know, talking about it.

But I think these lakes are kind of a little more out of sight, out of mind ’cause they’re shallow and they don’t have any fish in them, but they do have a lot of waterfowl on them.

And, of course, you know, the geese actually, you know, they actually -- they actually like this mud that’s full of fresh, green growth after the lake drains, and so the geese probably think it’s ok. But the loons, no, you know.

And these lakes all had -- you know, we have -- we have several species of loons that nest on these lakes, and they are out of luck when they’re gone because they need -- Well, a loon needs a pretty big lake just to be able to take off, right? LESLIE MCCARTNEY: Yeah. DAVID SWANSON: Because they’re a heavy bird.

And then they are -- they -- they feed by diving under the water and eating small fish and invertebrates, right? And so, once that’s done, they’re out of luck. LESLIE MCCARTNEY: Wow.

DAVID SWANSON: And so, we are concerned about -- about that. It is a big change.

Fortunately, there are some lakes up there that are of other origins that are not in danger of being lost, so.

LESLIE MCCARTNEY: So what are their other origins, then? DAVID SWANSON: Well, yeah. Bering Land Bridge is -- it’s just a remarkable park.

The geology of the Bering Land Bridge park is just amazing. And one of the features that we have up there is we have a -- we have multiple large lakes up there that, uh, formed by an explosion that occurred during volcanic eruptions.

So we, you know, if you live in Alaska you think about, you know, volcanoes being in the Aleutian Islands and that kind of thing, right? And not way up in the Seward Peninsula.

But in fact, there -- there’s a lava flow up in the Bering Land Bridge National Preserve that is so new that it’s black. It looks like the ones that you may have seen in Hawaii or it’s -- it’s probably, we don’t know how old it is exactly, but it’s -- it’s young enough that it -- it’s a big, black expanse, like, you know, like it was soon after it erupted.

I mean, it’s got lichens in here and there on it and that sort of thing, but, anyway, so this is actually a volcanic area, and -- and a few times in the past, um, there’ve been cases where the magma has risen up and encountered, you know, encountered this ice-rich permafrost, and the result was a big explosion.

And -- and then, a circular hole that later filled with water. And they’re known as maars, M-A-A-R, and so we have a -- we have, actually several maars in Bering Land Bridge National Preserve that -- and they are actually in a bedrock basin that is not threatened by -- by thaw of permafrost.

And thank goodness because those are -- those lakes, Devil Mountain Lakes is one of them, Killeak Lakes, Whitefish Lake, and they’re big, amazing lakes with -- LESLIE MCCARTNEY: They must be deep, too.

DAVID SWANSON: They’re deep, and they have a lot of fish because they’re deep. And they have a lot of loons on them, too. I mean, they have some loons, you know.

But they -- they’re different. You know, I mean, these shallow lakes, you know, are -- are very productive, and they have -- vegetation actually grows up in some cases from the bottom, you know, rather than like in one of those maar lakes where there’s no plants that are growing up from the bottom. You know, they’re too deep, you know. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: So anyway, um, so I don’t want to imply that all the lakes in Bering Land Bridge are going away. The maar lakes are not going away, and some of the other ones probably would manage to persist even if the permafrost thawed, but -- but in the meantime we are losing quite a few, and it’s -- it’s an unsettling and dramatic thing.

You know, when you fly -- like this year, one of them occurred. There was one lake drainage that occurred this summer, and I had not looked at any satellite images ’cause I was out there.

And we’re flying along one day, and we were actually going to -- you know, we were on the way to the coast, and I looked down, and, you know, it’s like, oh my God, here’s this huge expanse of mud, and this place that used to be a lake is gone.

And now, it’s just a big expanse of mud, and it was like, it’s going -- it’s still happening, you know.

LESLIE MCCARTNEY: So I take it, too, the water must be draining towards the ocean? Is it? DAVID SWANSON: Yeah, eventually it ends up in the ocean.

LESLIE MCCARTNEY: It ends up in the ocean. So how is that sort of changing the coastal region for the salinity, or is it enough water to really make a difference?

DAVID SWANSON: Yeah, you know, I think that it -- it’s, you know, briefly there’s a lot of flow going out, and then it’s kind of gone. LESLIE MCCARTNEY: And then it’s gone? DAVID SWANSON: You know, I think one thing about -- since these lakes are only -- they’re not very deep. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And so, um, the main thing you see is that there’s going to be a gully that you can see, it’s -- it can be pretty deep, and usually there’ll be a bunch of mud that’ll end up, like, let’s say in a neighboring lake if --

'Cause sometimes they drain out via a neighboring lake, and then eventually into a creek of some kind, and then they get out. So somewhere, you’re probably likely to see some mud.

But um, actually, it’s -- it’s remarkable how they -- the water is just sort of gone. There’s so much water up there that it’s almost like, you know, dealing with this one lake’s worth doesn’t really seem to -- LESLIE MCCARTNEY: Make a huge difference? DAVID SWANSON: Make a huge difference, right. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: It seems to be -- they seem to be able to accommodate it, and I think even -- even eroding the gully, you know, obviously, that -- that -- there’s a bunch of wat -- there’s a bunch of mud that gets swept out and ends up making the creek muddy for a while.

But even that, you know, in a permafrost region like this, a lot of the ground is actually ice, right? So it -- it turns to water, and it’s gone.

And there’s not even that much sediment in some cases. There -- becau -- I mean, there’s less sediment, I should say, than you’d expect because, you know, sometimes half or more of the ground is actually ice. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: So it’s not sediment. So it just melts and flows away.

LESLIE MCCARTNEY: So when it’s been doing it, is there a lot of sinkholes then that are appearing, too? I mean, if lakes are draining out and the ice is melting in the ground, sinkholes -- ?

DAVID SWANSON: Yeah, there are. Although, you know, it’s interesting, it’s not as -- it’s not as dramatic as you might expect. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: You know, like, I -- you know, like, if you look at, um, uh, if you look at, you know, like, I -- just today I was looking at some aerial photographs from the '50’s, and then one -- and then some satellite images that were taken last year that are -- or a few years ago, and looking -- looking at -- looking at that phenomenon.

And um, you know, here and there you see new pits and that sort of thing, but it isn’t, um -- You know, I think -- one thing about that landscape is that it’s still pretty cold up there, and there’s a lot of peat, you know. LESLIE MCCARTNEY: Yeah. DAVID SWANSON: Which is this organic stuff on the surface.

And um, and, you know, very dense vegetation on top of the peat. And so, it kind of reacts relatively slowly, I think, in a lot of places.

And so, the change is localized, and um -- so like, it doesn’t take very much subsidence if it’s along, um --

You know, I probably should digress a little more. So there’s this, um, the ice is -- is -- is in a peculiar form up there. There’s a phenomenon which people who have been to the Arctic have all seen, that otherwise you would’ve never seen. It’s called ice wedge polygons. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And uh, what happens is due to contraction in the winter, um, there -- the ground actually fractures just in a fashion that reminds you of mud cracking when it dries.

And that -- and those cracks go down into the permafrost. And then water in the spring flows in the cracks, and uh, and then freezes.

And then, because it’s permafrost, it stays there. And then, the cracking tends to occur multiple times in the same place, so you end up with this -- with this kind of wedge of ice, and that’s -- and that’s the form that a lot of that ice is in.

And you can see the polygonal pattern in the -- when you look down from the air. Um, it’s actually kind of hard to see when you’re on the ground, but from the air, it’s obvious that just the whole landscape is covered with these polygons.

And that -- and the ice is in, then, these wedge-shaped features, and when it melts, you end up with a little bit of a trench.

And that’s -- and -- and they’re linked up, right? And so, they’re ready-made to form a new -- a new lake outlet.

And so, it doesn’t take much thaw or much subsidence to make a new lake outlet.

And so, you can have a landscape where you don’t see a lot of new pits or holes, but just enough to -- to link up and make a -- and make a new drainage outlet for a lake.

LESLIE MCCARTNEY: Now you said that these -- the lakes that are draining right now are just in one particular area of the park? DAVID SWANSON: Well, one -- LESLIE MCCARTNEY: Or a concentration up there?

DAVID SWANSON: Yeah, you know, it’s -- it’s kind of -- I’ve studied, of course, you know, all across the parks I work for. LESLIE MCCARTNEY: Yes. DAVID SWANSON: Because it’s something that everybody’s concerned about.

And they are, of course, concentrated in the lakes that -- that are -- that are what we call thermokarst lakes. They’re lakes that are formed through subsidence in permafrost.

So those are the -- those are the ones that are really vulnerable to drainage. We have a lot of lakes that are like the maar lakes, that they form by some other process, and they’re not nearly as vulnerable to drainage.

So like, um, we -- like, for example, in the Noatak -- in the Noatak Preserve and in Gates of the Arctic National Park, most of the lakes, actually, are in depressions left after glaciers thawed away, and they’re -- they’re surrounded by good, solid ground. And they’re not draining very much.

I mean, once in a while. Once in a very rare occasion, you can erode an outlet, but you’ve got to erode it through solid ground. It’s not eroding it through stuff that's half ice. And so, those lakes are much less vulnerable.

And Bering Land Bridge has some lakes of other origins that are not as vulnerable, and -- like the maars, and they aren’t draining away.

So, but there’s this one part of the park that has had a lot of them, and it is a little mystifying because we do have fields of thermokarst lakes elsewhere in Bering Land Bridge and in -- elsewhere in the Arctic Network that haven’t had so many drainages.

And I think that, um, you know, to tell you the truth, I think it’s partly just luck. There may be some, you know, some things going on that are more explainable, but you know, when you have --

You know, every lake drainage event is to some degree, almost, you know, it’s a little bit of an act of God. You know, it’s a little bit of a random catastrophe kind of a thing.

And it can so happen that a bunch of them occur in one place, just like, you know, lightning might strike in a bunch -- you know, in a bunch -- you know, close -- close places, just kind of by accident.

And I think that some of these other parts of the park, on the far northeastern has been particularly hit with lake drainages. And -- and meanwhile, the western part, not so much.

But I -- I think it’s -- it will, you know what I mean? It’s just when you have a fairly small sample, you might end up losing a bunch from one area. And it’s just kinda by -- by luck, and I think that we’re gonna -- as warming continues, I expect other parts of the park to also show some drained lakes.

And they have already. I mean, like, you know, the western part of the park actually lost one mid -- sort of mid-size lake, about a half-mile across, last year, and it has lost some in the past. And it, you know, it’s going to affect everybody at some point.

LESLIE MCCARTNEY: Yeah. And then with it being warmer and the seasons being a little bit longer, how fast is the vegetation then coming and sort of reclaiming these drained lakes?

DAVID SWANSON: Um, the reclaiming of the vegetation has been remarkably fast. I -- I -- we were frankly stunned last year, um, to go back to, you know --

Well, I was on another project that caused us to fly over some lakes in 2019 that had drained in 2018, and they were absolutely, completely covered with vegetation.

And in some cases -- like, one of them was completely covered with a -- with a -- a plant that produces big, yellow flowers. And so, we had this -- so this lake was -- basically, it looked like a field of sunflowers. I mean, it was completely yellow. Even from a -- from a long ways away as we were flying toward it, it was like, that lake is completely yellow. It’s all flowers, you know.

And so, we had this field of flowers, and then the ground surface, actually, was covered by a small sedge, and it was like a golf green. I mean, it was absolutely solidly covered with plants.

And then another lake we went to that same day was -- didn’t have so many of the yellow flowers, but it had another type of plant that formed a solid lawn, to the degree that it looked like a golf course as you flew in.

Um, and then a third lake that we went to, actually, was not quite so completely covered with plants.

And it’s a bit of a mystery, but I think one thing we know is going on is that the mud is extremely rich in nutrients, and it’s moist, and it’s just the perfect place for plants to grow.

And there must have remarkably been a lot of seeds that were preserved or in the -- or potentially spores, because one of them actually was a plant that produces by spores. It was actually a horsetail. That were in the mud, and were able to, as soon as it became dry, poom! Come out of the ground.

Of course, they -- these plants are nothing like the ones in the surrounding area, and we’re hoping to study that as they -- as, you know, as the plants regrow, um, because, um, they --

You know, it’s going to be a long time before it resembles the terrain around it. And as a matter of fact, it might never.

You know, what's -- what’s an interesting, you know, thing that’s going on here is -- so, you know, historically when a lake would drain, permafrost would reform in the bottom, new polygons would form. It would -- the ice would accumulate. The surface would actually rise up again, and you’d end up -- over a period of centuries, it would eventually look a lot like the land that was around it orig --

And it would be ready to, basically, to form -- to thermokarst again. (clears throat)

But now, you know, with the projected, uh, you know, warming that’s already started, it may -- there’s probably places where the permafrost won’t reform in some of these lake bottoms. And so, they may end up not ever looking like the surroundings. Because, you know, when permafrost forms, of course, that certainly affects the vegetation.

And some of these, if -- depending on how fast warming occurs -- the last few years have been so warm that we think maybe it’s happening faster than the predictions originally were. Um, we may not get permafrost reforming in these lake bottoms.

LESLIE MCCARTNEY: Well, and with the warmer climate, too, there may be a big change in plants everywhere. DAVID SWANSON: Right. Yep.

LESLIE MCCARTNEY: Um, that could come with this. I mean, the tree line will start moving north. DAVID SWANSON: Right. LESLIE MCCARTNEY: Different animals will start inhabiting. DAVID SWANSON: Right, yeah, there could be -- LESLIE MCCARTNEY: It could all -- Could be a lot of different changes. DAVID SWANSON: Right, yeah. LESLIE MCCARTNEY: Yeah. DAVID SWANSON: (whispered) Take a break. LESLIE MCCARTNEY: Yes, we can take a break. (break)

LESLIE MCCARTNEY: Ok, so we’re back. Thank you very much, Dave. DAVID SWANSON: Yes.

LESLIE MCCARTNEY: So we were talking about the lakes, um, the drainage of lakes and the different flora that’s inhabiting. You also said you worked on coasts. So have you worked on the coastal area of the Bering Land Bridge, and has there been any large changes that you’ve observed there?

DAVID SWANSON: Yeah. So uh, yeah, we’ve been using these old -- old photographs to -- to follow the changes in the position of the coastline over time, and that’s been the main thing that we’ve -- that we’ve done.

I’ve done some other projects that have taken me to the coast, and I love it there. It’s just -- it’s just -- it’s a really amazing place. It’s just, uh, there’s so much wildlife. There’s so many birds. And -- and it’s just -- it’s, uh, you know, miles and miles of pristine beach, basically, right?

It’s the kind of thing that, you know, we have -- we have -- most of our coast is barrier -- is barrier islands, which are these -- you’re probably familiar with that. You have a beach, and then you have, usually some sand dunes, vegetated sand dunes, and then salt marshes behind. And then behind that is a lagoon.

And much of the northern part of the Bering Land Bridge park has that, um, kind of a coastline. And, you know, there’s a lot of barrier islands in the rest of the country, and they’re covered with condos and uh, you know, there are seawalls all over the place, and it’s just -- it’s kind of a mess, right? And our -- ours are just pristine, they’re perfect.

And uh, anyway, that’s -- and so one of the -- so one of our monitoring projects has been to look at the changes in the position of the coastline, basically. We, um -- and what we’ve -- what we’ve observed is that it is -- it’s in -- it is indeed eroding back in a lot of places.

Most of -- most of the coast of Bering Land Bridge is actually this beach and dune kind of coastline, which -- so that the waves are not actually crashing against permafrost on most of the coastline. They do more so on the -- as you round the -- so, you know, part of Bering Land Bridge faces north-northeast, basically. And -- excuse me, north-northwest. But then you go around the corner, and there’s an east-facing coast, too.

And that is more perma -- that’s more where you have like a permafrost bluff with the waves touching that. But on the north side, it’s mostly the waves are mostly actually on beach.

And that area, it’s been retreating inland, although -- and the rates are rapid in some places. Although, you know, from looking at the older photographs, it appears that they’ve been doing that for a while, and so it’s not completely, um, it’s not a completely new, sort of warming-related process.

We think that it -- it seems to be more active than it used to be, both erosion and deposition in some places, because the sea ice is not there nearly as long as it used to be. And so, it’s more active, and the rates of erosion and the movement of the shoreline in are probably speeding up in places.

But the thing we have going for us is that we have, um, these beautiful beaches which are -- with natural vegetation on them, that are doing a pretty good job of resisting the change.

So, you know, they -- you know, that coastal vegetation and those coastal land forms were built by -- by waves and storms, and they -- and they can do a pretty good job if left -- you know, left alone and not destroyed. They can do a pretty good job at, you know, at protecting -- at protecting the lagoons that are behind.

LESLIE MCCARTNEY: Right, yeah. And the saltwater marshes, too? DAVID SWANSON: Yeah. LESLIE MCCARTNEY: They’re still being protected? DAVID SWANSON: They -- they seem to be doing ok for the moment. You know, there’s been some loss in the estuaries. LESLIE MCCARTNEY: Um-hm. DAVID SWANSON: You know, that’s where the rivers come out.

There’s been some erosion back of the salt marshes at the mouths of the estuaries. Um, and -- but a lot further behind still seems to be ok. And the ones behind the lagoons are mostly ok.

It’s been interesting, you know, with the -- one -- one’s kind of side effect of -- you know, it’s probably a warming-related thing, is that the vegetation on those barrier islands, um, actually it seems to be getting a little denser than it used to be. Because plants do a little better when it gets a little warmer, right? And so, you know, so we actually seem to be gaining a little vegetation.

There’s places where, you know, in -- there’s places on the barrier where during big storms, the waves actually come -- go completely over. And most of it is vegetated and has a nice dune, and that sort of thing, it kind of protects it. It’s like a, you know, it’s sort of like a breakwater.

But there are places where the waves actually manage to breach it. And when they do that, they -- and they always have, right? This isn’t completely new.

They breach it, and they deposit sediment back behind, and that’s what will someday be a salt marsh after the, um, after the barrier kind of reestablishes, and the -- and you know, a berm kind of builds up. And they -- and so, some of those places have actually shrunk a little bit as the vegetation has encroached.

Um, and, you know, since we’ve started monitoring, that -- we’ve actually seen more of that happening than new breaches.

Um, but, you know, I still think that we are -- we are concerned about the rate of erosion just because there are a lot of cultural sites in the park. Some of it’s on private land. A lot of it’s actually on private inholdings, but, nonetheless, those are at risk from the coastline moving inland.

Even -- even if -- you know, even if it wasn’t being speeded up by, uh, by climate change, which it has, um, that would still be a concern, I think.

But there’s definitely -- you know, I don’t study the, you know, the climate per se, and the storms and stuff, but I -- but we had a graduate student, Louise Farquharson, who -- who was working with us on the coastal change, and she summarized a bunch of data on the sea ice situation.

And uh, it’s been -- I think -- I think her results were that over the past thirty-five years, the -- the length of the season lacking ice has -- has increased by about five days per decade, I think is what she determined. So you’re talking about now over the case of four decades, you’re up to about twenty days longer of a season without ice than used to be.

And that’s occurred mostly thanks to the ice coming later in the fall. Um, you know, there’s -- our falls just have gotten milder and milder, and so there’s less ice and a little more action on the coast.

And, of course, and yeah, and more erosion occurring then. And more deposition. You know, there’s part of the coast, out at the Cape Espenberg end, um, is actually where a lot of that sediment goes that gets eroded from the rest of it.

And so, that area actually is building outward, and that’s where -- and that’s where a lot of the archeological sites are, too. So that’s a nice coincidence is that -- well, it’s not entirely coincidence that the archeological sites are there, in part because it’s this point that, you know, was a good place to be, and it was building out all the time.

And since it was building out, all of the, uh, the old archeological sites didn’t get eroded away thousands of years ago. And so, and so as you -- as the -- as the beach builds out, it leaves back behind, um, you know, all the old camps that were there prior are preserved on the old beach ridges.

And so, um, there’s, you know, there’s been a lot of really interesting archeology that’s been done on Cape Espenberg. And that’s an area that’s not at risk from erosion at the moment because it’s actually where the sediment is going.

LESLIE MCCARTNEY: Yeah, being dropped, yeah. Interesting.

DAVID SWANSON: Yeah. And so the old -- the old remains are -- you know, the archeological artifacts, et cetera, are actually further from the ocean than they used to be as the beach builds out.

LESLIE MCCARTNEY: Right. Interesting. You had mentioned earlier that there was large changes like the lake draining, and then you said there’s a lot of subtle changes that are happening. What would be some of the subtle changes that are happening?

DAVID SWANSON: Well, um, you know, the vegetation changes for the most part, I would call subtle. You know, I mean, locally, there’s this dramatic things, like the -- like the yellow flowers on the lakebed, right? LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And -- and some more dramatic things, like the vegetation encroaching on those overwash areas on the bank -- on the ocean. But, you know, for the most part, vegetation change has been -- has been gradual, and um, fairly difficult to detect for that reason.

And I think, you know -- and the reasons are that it’s, you know, even with warming, it’s still the Arctic. Plants grow slowly, and uh, they don’t, you know, not a lot’s happening, you know, fast anyway.

And then the other thing is that a lot of the -- a lot of Bering Land Bridge park is, it’s rolling, gently sloping tussock tundra, or it’s flat, wet sedge tundra. And both of those landscapes have a dense cover of sedges or sedges and low shrubs. And under that is a thick layer of peat, which is basically organic remains of plants that have been there before. Um, and there’s usually quite a few mosses and lichens, too, you know, amongst the sedges.

And that -- and those landscapes are actually quite -- they have a lot of inertia, I guess you’d say, kind of from an ecological sense. Is they -- it’s -- it’s difficult for new -- for a new plant to find a foothold there.

So even if -- even if the temperature is rising and in principle, you know, some other plant could colonize that site, it’s going to have trouble getting there.

And so, I think that those landscapes are likely to exhibit slow change. On a, you know, from the perspective of a human lifespan, right? A lot of that landscape is going to be slow to change.

Places that change faster are ones where there’s bare soil exposed, right? And -- and new plants can say, "Oh." Yeah, they can -- they say, "Well, it’s warmer now. I can -- I can get in here." And so, um, of course the lake drain -- the drained lakes are one.

River -- river bars and those kind of things are another place where, you know -- there used to be more bare river bars than there are now. And they've -- and this has happened statewide, actually, is that they’re getting colonized by shrubs and, well, and herbaceous vegetation, too.

And it’s something that -- it’s really dramatic in some places like Denali Park, and that kind of thing. But it’s occurring everywhere.

And we -- and we’re, you know, and across the Arctic, there’s also been some increase in shrubs, particularly tall shrubs, and that’s something that we’ve seen in a lot of places.

And that -- and that has this kind of a cascading effect. The wildlife that depends on shrubs, then, is expanded with it.

And we’ve seen some of that in Bering Land Bridge, although it’s -- it’s a gradual process that is, um, that’s kind of held back in these places with the waterlogged acid soils. It doesn’t really happen there so much.

So in some of the more sloping areas, particularly in the southern part of the -- in the southern part of the preserve where, um, where it’s -- there’s a little more -- little more bare ground, not quite so dense a vegetation, little bit better drainage, maybe not quite so acidic, um, there we’ve seen some increase in the shrub cover and increase in shrub height.

You can look at old air photos and you’ll say, "Ok, I see a clump of shrubs here that didn’t used to be there." But it’s -- it’s fairly -- it’s fairly subtle.

And another thing that’s nice from our perspective is that they’re still all native plants. You know, we don’t -- um, you know, it’s kind of funny, you know, you work for the Park Service, and there’s a lot of concern about invasive species and that sort of thing. Um, you know, and even in Denali Park there’s some invasive species along the road. And, of course, in some of the Lower 48 parks, there’s whole ecosystems that are partly replaced by invasive species and that kind of thing.

And then there’s the parks I work for where it’s like, actually, we don’t have any documented invasive species in the Bering Land Bridge right now. It could happen, for sure, I mean, because there are some in Nome, for example, and we could get one there. But, at the moment, you know, fingers crossed, there aren’t any. It’s a real luxury, really, to have that situation. LESLIE MCCARTNEY: That’s wonderful. Yeah.

DAVID SWANSON: And so, the plants that are -- that are expanding on the flood plains and in the drained lakes and on the overwashed fans and things, are -- are so far, they’re all native species. And, basically, you know, they’re -- they’re welcome there, you know.

But they are -- they are bringing with them, as I was mentioning before, wildlife that’s new in some ways, you know. And there’s a variety of species that, you know, wildlife species, that depend on shrubs and do better when there’s more shrubs, like moose and ptarmigan and beavers. LESLIE MCCARTNEY: Beavers.

DAVID SWANSON: All of those are -- and all of those are probably expanding in parts of the Arctic for that reason, because the shrubs make new habitat for them.

LESLIE MCCARTNEY: Yeah, we’ve had a couple people talk about how the beavers have kind of moved in and are sort of re-creating the landscape wherever they go in Bering Land Bridge Park. DAVID SWANSON: Right. LESLIE MCCARTNEY: Yeah, so that’s interesting.

DAVID SWANSON: Yeah, and so far, you know, it -- their -- their effects have been fairly localized, but we only expect it to continue. LESLIE MCCARTNEY: Right. DAVID SWANSON: You know, as it -- as the habitat gets better for them.

LESLIE MCCARTNEY: Yes. And the moose, too. DAVID SWANSON: Right. LESLIE MCCARTNEY: That’s interesting that moose are now moving in, too. DAVID SWANSON: Right. And there’s parts of -- there’s parts of the park that still don’t have very good moose habitat, but presumably, they will here at some point.

You know, I mean, depending on how far along this warming goes, you know. Um, the moose -- moose certainly could expand.

You know, it -- when you get out to the very northernmost coastal part of Bering Land Bridge, um, there are still very few shrubs except for the dwarf shrubs. Um, but in terms of, like, the willows and the taller ones that moose like, um, and beavers, too. There really are almost none as you move way out into those really windy, cold places along the coast. LESLIE MCCARTNEY: Right, yeah.

DAVID SWANSON: But further inland, where it’s a little bit warmer in the summer and that kind of thing, yeah. There’s -- there are getting to be a fair number of shrubs in places, and the moose are doing well.

LESLIE MCCARTNEY: Right. So do you manage to get up, then, every summer to the park, or -- ? DAVID SWANSON: I, you know, I -- I don’t get -- I don’t get to every park every summer. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: So like, I -- I’ve been fortunate to go to spend parts of the last two summers in Bering Land Bridge. Um, but I -- I may not get up there next summer. Actually, I’ve been -- actually, it’s been more than that. I’ve been -- I’ve probably going three or four in a row to Bering Land Bridge.

But it won’t happen every year, because I’m -- you know, if I’m in Bering Land Bridge, I’m neglecting Gates of the Arctic or something, so. So I -- so I -- but I like to get up -- I like to get to all, you know, all the places that I’m kind of responsible for, um, at least every -- every two or three years. Not every year is realistic.

LESLIE MCCARTNEY: So are you noticing these vegetation changes, too, in the other parks that you monitor? DAVID SWANSON: Yeah, I do.

And although I have to admit that it’s mostly -- it’s not something that I can detect, like, oh, I remember when I was here, it was different. You know, it’s -- it’s detectable by looking at these old aerial photographs.

And -- and because of the slow rate of change, except in the case of fires, which really are fast. But the -- this expansion on the tundra kind of thing, you really have to go back to photographs taken in the '80’s to really be able to -- and you compare those, so you have, like, forty years of time. And then you can really see the changes.

But I personally, it’s not fast enough, except in the case of fires.

LESLIE MCCARTNEY: So has there been many fires, then, in the Bering Land Bridge? I mean, there’s not a lot of -- well, you say there’s more shrubbery now. DAVID SWANSON: Yeah. LESLIE MCCARTNEY: But um, there’s no big, tall trees like the fires we get around Fairbanks. DAVID SWANSON: Right.

LESLIE MCCARTNEY: So can you talk to -- about fire? DAVID SWANSON: Uh, well, you know, tundra will burn. LESLIE MCCARTNEY: Um-hm. DAVID SWANSON: You know, and it’s -- it’s more like a prairie grass-fire kind of a deal.

And actually, there have been some huge fires in the past in Bering Land Bridge. And not many recently, but there have in the past.

And actually, one of those, you know I mentioned that there had been very few permanently marked vegetation monitoring plots, but actually, a scientist by the name of Chuck Racine, who recently passed away, had put in some plots in Bering Land Bridge in the '70’s, actually, and uh, they -- they had a fire go through there. I hope I have my dates right here. I believe that he put them in the '70’s, and the fire went through in the early '80’s, and then he was able to revisit them.

And then -- and we’ve continued to revisit those plots because they marked them. And actually went back there last summer, and that was an interesting place where having the fire go through, at least locally, can make -- open up some space for new plants to come in.

And so we did get a shrub increase on that fire, not everywhere, but in parts of that fire showed an abrupt shrub increase.

And that was, you know, as a result of -- it actually occurred back then, back when we weren’t thinking about warming. Although actually, you know, warming was probably already starting in the '80’s, and so some of it might have been -- it’s hard to tease out what was, you know, kind of a fire effect, and what was a warming effect.

But anyway, some of that -- some of the places in that fire, um, had new shrubs get established then in the '80’s, and they’ve persisted and gotten taller since then. LESLIE MCCARTNEY: Hm. DAVID SWANSON: And it was -- it was real interesting for me to get to go back to that place.

And as an aside, speaking of changes, while we were there, it’s -- so one of the reasons that this particular site was chosen is because it was, um, it was an easy place to land a floatplane, right? It was by, you know, a lake that was big enough to land on. In the southern part of the park there are only -- there are not very many of those.

And so, anyway, so we landed on this lake, and we were camped on this lake, and we were doing this vegetation measurements. And the beach that we were camped on was covered with dead grayling. And uh, just -- just hundreds and hundreds of dead fish.

And they were -- some of them were kind of old and rotten, and some of them were -- looked like you could pick ’em up and cook ’em. I mean, they were -- they were fresh.

And um, and I -- after I got back, I did some, you know, emailing around to people who work -- Fish and Game, uh, biologists and that sort of thing. And I don’t recall the names of the people that I consulted with right now, but the story I got back was it was probably because the water got too warm.

And they -- it’s a shallow lake, and the one we were on it's Imuruk Lake is where we were. It’s a shallow lake, and, you know, it’s -- if -- if it gets too warm, they run out of oxygen. And grayling, you know, are not real adapted to that. They’re a cold-water fish, and so they -- they really had no other explanation.

They’ve -- they’ve seen fish die-offs here and there in recent years due to warmth, and last summer was phenomenally warm, particularly up there, you know.

There was people -- were, you know, were paddleboarding out in the Bering Sea off of Nome ’cause it was in the 80’s, and it was calm, and, you know -- And it was in the 80’s where we were, too, inland, of course. And Imuruk Lake got so warm that there was this big die-off of the fish.

And I -- you know, we were only in this one little section of it, but um, we had a bear come by, um, and I -- I was concerned about camping on this beach full of dead fish, you know, because this is grizzly country, right? And you normally are very fastidious about not having anything to attract bears around your camp, right?

So we had a bear come by one day, and it just -- it just strolled down the beach, ignoring those fish. And the only way I could explain that was that there were so many beaches full of dead fish on that lake that he was full. ’Cause why else would a bear not be eating a dead fish, you know, if -- LESLIE MCCARTNEY: Yeah. DAVID SWANSON: It just shouldn’t happen, right?

LESLIE MCCARTNEY: Yeah. Well, that’s why I was going to ask you about the bears. I mean, gosh, that many fish, it would just attract bears.

DAVID SWANSON: And, you know, we were only there for about four days, so who knows. But there was not a lot of sign of bears on this thing. And maybe they hadn’t found ’em yet, I don’t know. It was a bit of a mystery to me.

But this particular bear, I can’t think of a single good reason why he was not stopping and eating those fish, other than that he had already had his full, you know. LESLIE MCCARTNEY: Exactly. DAVID SWANSON: Course, why he was still cruising the beach at that point, I couldn’t tell you either, so anyway. I guess that’s why I study permafrost and vegetation.

LESLIE MCCARTNEY: Um, I’m just going to look through some other things that we had itemized out. The project to actually talk about.

Willows. Have you seen a big -- other than the far north, you said it’s very cold and windswept. Have you seen a big increase in the willows? You said bushes, but willows?

DAVID SWANSON: Right. It’s -- it’s -- yeah, you know, alders -- alders and willows are the ones that have increased, but as I was saying, it’s not been -- it doesn’t represent, yet anyway, you know, kind of like a -- a reconfiguring of the ecosystem or anything.

It’s just -- it’s kind of a subtle -- you know, where there were already willows and alders, they’ve gotten a little more dense, um, and a little taller, and that kind of thing. But it’s not like they’re appearing in places where they’ve never been, and suddenly where you used to be able to walk, you can’t. It isn’t like that yet. It’s, um, it’s, thank goodness, a slow, slow process for the moment.

LESLIE MCCARTNEY: Yeah, so you’re not noticing them kind of racing up riversides, riverbeds, or anything like that, nothing?

DAVID SWANSON: No, it’s just been a, you know, a slow, kind of a gradual infilling.

And, you know, like I was saying, the gravel bars used to be a little bigger than they are now because they -- they’ve kinda -- the willows have encroached on them a little bit.

Um, and some of these -- some of these mountainsides that used to have, you know, a smattering of willows, they’re a little thicker than they used to be. And alders, too. But it’s not -- fortunately, it’s not -- uh, yeah.

And it’s probably enough that the wildlife has noticed. But it -- I guess from the perspective of a scientist, you have to work pretty hard to document it. You know, so I -- I -- so for me to, like, write a report and want to say how much it’s changed, I have to work pretty hard to figure out a way to measure it on those photographs. LESLIE MCCARTNEY: Right. Right. Interesting. DAVID SWANSON: Yeah.

LESLIE MCCARTNEY: Um, yes. What -- ok. You haven’t seen any invasive species. Because that was one of our things that we wondered. DAVID SWANSON: Right. No. LESLIE MCCARTNEY: Like vetch or hawksbeard or nothing? DAVID SWANSON: No. LESLIE MCCARTNEY: Nothing?

DAVID SWANSON: No. And, you know, they could come in on somebody’s wheels or something at some point, but they haven’t yet. And that’s where -- that’s what was one of the fun things about visiting those lakebeds was that those were all native species.

And there are -- we have a few plants that are, um, specialists in occupying new, open habitats, and they were the ones that were there, you know. And you don’t see them very often because we don’t get, you know, because our landscape is predominantly, you know, this very kind of stable tundra, uh, that there isn’t a lot of disturbed ground with a lot of these kind of plants growing on them.

And so, that’s why it was really fun to go out and see them ’cause you don’t usually -- we just don’t see ’em that often.

LESLIE MCCARTNEY: Well, you just wonder how many seeds were laying at the bottom of one of these lakes for, you know, a completely yellow thing to be there. I mean, how many thousands of years, or hundreds of years, have they been laying there? DAVID SWANSON: Yeah. LESLIE MCCARTNEY: Just waiting.

DAVID SWANSON: Right. You know, and I can’t discount that there may have been a generation, you know, like some blew in from the shore. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: But I just -- you know, they -- those yellow flowers were pretty dense all the way out to the middle, and I have to believe that they actually were dormant in the mud. I can’t think of any other way that it could’ve happened. LESLIE MCCARTNEY: Exactly, yeah.

DAVID SWANSON: You know, uh, right. And then, the little -- the little sedge that formed the carpet, too. There’s just no way that it could’ve grown any other way other than having them be out there already.

LESLIE MCCARTNEY: Right. Blown in on the winds and been there for decades, probably. DAVID SWANSON: Yeah. And just getting buried in the mud. And just waiting for their time, you know. LESLIE MCCARTNEY: For the perfect time.

DAVID SWANSON: Yeah, and they were, you know, they were the kind of plants that grow on the shore in little muddy spots, and I just had no idea that they were all the way out into the middle and ready to go. LESLIE MCCARTNEY: Yeah. Yeah. DAVID SWANSON: When it finally drained, you know.

But we’ve had, um, you know, one thing that we’ve been -- you know, we have these weather stations, you know, and we’ve been monitoring the ground temperatures.

And there’s -- it was, you know, we were -- I think we were kind of lucky in Alaska, um, in the, um, you know, we had a kind of a warm spell in the late '70’s, um, and then we went into what should’ve probably been kind of a cold spell over a period of decades that -- that didn’t really turn out to be one, because of -- probably because of overall global warming.

But in Alaska, it made it so that our climate was kind of flat for a long time, and -- and a lot of the changes, I think, were damped out a little bit. And then -- but that’s over now.

And since about 2014, um, the -- the warming has just, you know -- kind of that phase we were in, that kind of relatively cold phase, um, went away. And since then, it’s just been remarkably warm.

And that’s, I think, you know, part of what’s triggered the lake drainages. And -- and it’s also something we’re seeing in the temperatures that we monitor, so I, um -- you know, so we have these, basically, thermometers in the ground that we use to monitor, um, the -- you know, to basically to see if the permafrost is still safe, or whether it’s on the verge of thawing, right. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And we have had a -- a big jump in temperatures in the last, about five years, and um.

LESLIE MCCARTNEY: Can you quantify? What is a big jump? DAVID SWANSON: Um, well, uh, yeah. No, that’s a figure I should’ve looked up before I came. LESLIE MCCARTNEY: That’s ok. No. DAVID SWANSON: I don’t -- LESLIE MCCARTNEY: No, like a couple of degrees? DAVID SWANSON: Yeah, more than that. LESLIE MCCARTNEY: Celsius or Fahrenheit? DAVID SWANSON: Celsius. LESLIE MCCARTNEY: Um-hm. DAVID SWANSON: I think more on the order of probably three degrees Celsius. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: And um -- but, you know, of course, and there’s a good chance that it’ll maybe revert partway back. We’re hoping so, right?

I mean, we’re hoping to have a good, cold winter and -- and maybe, you know, hoping that this is maybe a peak that we’ll recede back from.

But it certainly hasn’t -- it’s certainly been persistent for several years in a row now. Um, and it’s gotten warm enough that, let’s say -- so I’ll have to digress a little bit. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: So when the -- you know, if the -- the permafrost, basically, exists because of a cold climate, right? And -- and if it -- and the permafrost can be, um, you know, like, you can -- if your -- if your -- if your climate is cold enough, your permafrost can be well below freezing, right? It can be -- it can be ten degrees Celsius below freezing in a really cold part of the world.

But in places where it’s not so cold, then permafrost sits near freezing, or closer to freezing, and only a small amount of warming is enough to kind of do it in.

And uh, in Bering Land Bridge, we were fortunate, you know, to start off this whole warming business with fairly cold permafrost. Not as cold as the North Slope, but colder than, say, for example, the Fairbanks area. And so, our permafrost was more in the vicinity of, maybe, minus three to minus five Celsius, um, to start off with.

But, so that means that we had sort of, um -- if we had a little bit of a, sort of a cushion. You know, if it warms up, then you can get some local permafrost thaw, but the big picture is that it’s still there. And that is still the case where we are now.

LESLIE MCCARTNEY: And how deep do you put the sensors? I mean, ’cause, you know, three degrees is going to warm up the top, but it’s not gonna warm up twenty-five feet below the surface. DAVID SWANSON: Right. LESLIE MCCARTNEY: So how deep are your sensors?

DAVID SWANSON: Well, the sensors we -- you know, since working in a national park, we can’t -- we can’t bring in a big drill rig and put ’em in deep. So what we have to do, is we actually put them in just in the top meter. LESLIE MCCARTNEY: Ok.

DAVID SWANSON: Um, but what -- but there’s a -- a -- a sort of a fortunate thing about soils is that if you -- if you average the temperatures through the year in the top, that will give you the same temperature as you would get down further.

So uh, you can get away with not having a deep borehole, although we love deep boreholes where we can get them, and there are deep boreholes along the Haul Road, for example, that we -- you know, that we watch with great interest.

Um, but we -- we actually are just using sensors in the top meter that we average. Because what happens is, um, this is just sort of a fun fact about the ground, is that the ground is an average -- you get down far enough, and it doesn’t warm or cool much, winter and the summer. It kind of sits at the average of what is going on at the surface.

And so, that’s why if you go in a cave, for example, a deep cave, the temperature’s going to be kind of constant year-round, and it’s going to be right near what the average is up at the surface.

The same’s true of water out of a well, by the way, too. So that’s why we had this, in Fairbanks, we had this nice ice water year-round coming out of the ground just above freezing because that’s what the temperature of the ground is.

And so, anyway, we can get away with just measuring near the surface. And what we’ve seen is that the temperatures have come up closer to freezing, but they aren’t -- they haven’t crossed the threshold yet. LESLIE MCCARTNEY: Ok.

DAVID SWANSON: But because of this kind of rapid warming that we’ve seen in the last five years, our cushion is not as great as it used to be.

And, of course, in places like Fairbanks, we’ve probably made the jump, and our permafrost here is probably degrading in a lot of places. LESLIE MCCARTNEY: Yeah. DAVID SWANSON: Because it is no longer cold enough to maintain it.

LESLIE MCCARTNEY: Right. So these weather stations, do they also take temper -- weather statistics of the atmosphere around, too? DAVID SWANSON: Sure. LESLIE MCCARTNEY: So what’s going -- DAVID SWANSON: Right.

LESLIE MCCARTNEY: So have you noticed, um -- I don’t know if a weather monitoring station would do this, but a spike in storms or intensity of storms, or, um -- ?

DAVID SWANSON: Well, we -- so um, we measure, um, yeah, temperature, rainfall, and wind. And uh, you know, I don’t, uh, I don’t think that we’ve analyzed the data in a way that we could recognize that. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: You know, the problem there is, um, you would have to use -- you would probably need to go to Nome or Kotzebue to have a long enough record to see it.

You know, because storminess is something that you'd probably need -- even -- even just to understand temperatures. There’s so much fluctuation that um, for that kind of thing, if you wanted to document a long-term change, you would probably need to use a long -- one of these long-term weather stations.

And those -- those are incredibly valuable. I use them all the time. I mean, I love our weather stations that we’ve put in that have been in for ten years because they really help me understand what’s going on in the short term, but you’re always asking yourself, "Ok. You know, here’s what’s happened. This is the warmest year that we’ve had in our ten years. What does that mean, you know?"

Well, then you can look at Kotzebue and find out that, not only is it the warmest year in the last ten years, it’s the warmest year since history began at Kotzebue, and it’s warmed by several degrees. Ok. Well then, now that gives you a perspective that you didn’t get from your short-term record. LESLIE MCCARTNEY: Right.

DAVID SWANSON: And that’s why we really, um -- you know, it’s -- it’s really valuable to have those. And that’s what you’d have to do, I think, to document the storminess. LESLIE MCCARTNEY: Right. No, I just -- was just -- wondered.

DAVID SWANSON: And I think anecdotally, I’m sure other people who you’ve interviewed have -- have -- LESLIE MCCARTNEY: They’ve mentioned storms. DAVID SWANSON: -- talked about the storms being crazy. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And that’s something that I think is, um -- something you could probably tease out of the data from one of these long records, if you tried. LESLIE MCCARTNEY: Right. Ok, very interesting. DAVID SWANSON: Yeah.

LESLIE MCCARTNEY: Um, I’m just going -- we’ve talked about timings of freeze-up and break-up. Freeze-up, you said in the fall is happening later. DAVID SWANSON: It’s happening later, yeah. And that’s -- and so, that’s what the sea ice is coming, you know, like I was saying, every -- every -- as every year ticks by it, on the average is coming later.

And another thing that I’ve studied is, um -- I’ve studied green-up from using satellite -- LESLIE MCCARTNEY: Hm. DAVID SWANSON: -- satellite images.

And um, ’cause you can see the vegetation, you know, it turns green. And the nice thing about satellite images, you can get the big picture, right? And the whole, you know, the whole landscape turns green, and you can see it on the satellite images.

And uh -- and uh, it’s definitely getting earlier, although I think it’s -- one thing about the warming that we’ve had so far is that it’s affected winter more than summer.

Um, you may have heard people talk about that in particularly. Which means that it certainly affects permafrost because permafrost depends on winter and summer.

And -- and winters are coming later, particularly in these coastal areas, and -- and uh, but, you know, the warmers -- the winters just really aren’t as cold as they used to be.

And the summers, um, the summers have warmed, but not as dramatically. And so that’s, I think, one of the reasons that maybe, that our vegetation changes have been a little bit subtle is that, uh, is that the vegetation’s growing in the summer.

And the green-up has been coming earlier, too. And the way I’ve -- the way I was able to document that was kinda, I had to do it kind of indirectly.

So I had -- I had about twenty years of satellite images. But, you know, even twenty years, there’s so much year-to-year variation. Green-up would vary by a month, depending on what year you were in.

And even recently, there have been some pretty -- pretty late springs. Like 2013, I believe, was one that was just super late. It was here and up there.

Um, and so, it’s hard to get a trend out of the satellite record. But what I was able to do was I was able to relate the timing of the green-up to, um, basically how much warm weather had occurred in Kotzebue that season.

So in other words, you could look at the temperatures in Kotzebue and say, ok, after a certain number of warm days have occurred in Kotzebue, that coincided with when green-up occurred in, um, the places that are kind of represented by Kotzebue, which would include northern Bering Land Bridge and parts of Cape Krusenstern and Noatak Preserve.

And so, what I do is I found a pretty good relationship between what was the temperatures in Kotzebue and when green-up occurred over the last twenty years. So then I could take, ok, Kotzebue weather records go back to the '30’s. And so, I was able to then reconstruct, ok, when would green-up have occurred, based on the weather station at Kotzebue.

And it turns out that, um, green-up is definitely occurring later. Um, and particularly these really extremely late years don’t happen as often as they used to.

But it hasn’t changed as much as the sea ice, so I -- I determined that back in the '40’s, on the average spring occurred about a week later than it does now. So it’s not nearly as dramatic as the sea ice change.

And it’s just probably, I don’t know, it’s just probably because of that whole -- the whole business of warming affecting the winters more than the summers, and springs still are kinda -- kinda slow to get here. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And we expect that trend -- I expect it to continue.

LESLIE MCCARTNEY: So with a warmer winter, are you finding that the snowfall depth is -- is greater? DAVID SWANSON: Well, that, you know, I don’t know if -- you know, I -- I -- that isn’t something that I -- LESLIE MCCARTNEY: You don’t study that? DAVID SWANSON: Yeah, they -- LESLIE MCCARTNEY: Right? Yeah. DAVID SWANSON: You know, we do have the climate people that are studying that. LESLIE MCCARTNEY: Right. Yeah.

DAVID SWANSON: And I think -- and what I do -- what I do know is that we’ve had a couple of record -- record deep snows the last few years. And, of course, the people in Nome and Kotzebue really are talking about that.

And -- and so -- and I think that, you know, that -- it’s undoubtedly related to warming, right? Because you’ve got all of this moisture now that didn’t used to get here. LESLIE MCCARTNEY: Right. DAVID SWANSON: Yeah. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And -- and I think that helps explain, um -- that helps explain the lake drainages, you know. But, you know, in some -- in some ways, it isn’t helping the vegetation any, because, you know, uh, you know, like there was some snow drifts that took forever to melt out last year because of the -- because, you know -- And the plants had to wait until that was done.

You know, and I remember -- I remember, like yeah, I think -- I remember flying back from, uh, the park last July and seeing some shrubs that were still melting out of the snow. Um, you know, and we have snow that doesn’t melt until July. That isn’t new.

But this -- this snow was melting out of a place that had shrubs, meaning that normally, there was not snow there in July. LESLIE MCCARTNEY: Right, yeah. Yeah. DAVID SWANSON: Yeah.

LESLIE MCCARTNEY: Wow. Um, let’s see. What other things? Can you think of anything else, Dave, that we wanted to just sort of mention about changes that you had -- we’ve talked a lot about permafrost.

DAVID SWANSON: Yeah, I just had made some notes about -- LESLIE MCCARTNEY: And sea ice. Yeah, please, whatever your notes are.

DAVID SWANSON: You know, I think, um. No, I think, you know. I’ve talked a lot, and I think I’ve -- LESLIE MCCARTNEY: It’s been wonderful. I’ve learned so much.

DAVID SWANSON: Well, good. I hope that the listeners find it -- find it interesting. LESLIE MCCARTNEY: Yeah.

Is there any other changes that you -- that come to mind that we really haven’t touched on very much? DAVID SWANSON: Oh, you know, one here that I saw -- I saw that you have mentioned. LESLIE MCCARTNEY: Yes. DAVID SWANSON: Was um, lichens. LESLIE MCCARTNEY: Yes. DAVID SWANSON: Which are something of interest, right? LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: Because lichens are, um, well, they’re -- you know, they’re pretty abundant in the Arctic, and they’re really interesting. And -- and if you get down on your hands and knees, they’re very pretty, too.

And they are also a important winter food for caribou and reindeer, which are domesticated versions of caribou, right? And so, we are very interested in what the situation with lichens has been.

And -- and so, we’re monitoring them, and they change very slowly. I mean, lichens grow incredibly slowly, so we don’t expect to see a lot of change.

Although we have set up plots that are permanently marked that we hope that maybe future workers in the park will be able to use to document change in lichens.

But one thing that we have noticed, um, is that, uh, in -- in recent years, the -- the caribou from the Western Arctic Herd have been coming onto the Bering Land Bridge park and onto the Seward Peninsula a little bit more than they had for quite a while and eating lichens.

And uh, there also are some caribou that have started -- have stayed through the summer and calved in the park. And in the Bering Land Bridge, you know, in the Seward Peninsula. Um, or near the park or in the park.

And um, so, you know, we have noticed that there’s been quite a bit of caribou grazing on lichens in the park. And that’s probably the biggest change that we’ve noticed in lichens.

LESLIE MCCARTNEY: Now is that because of where they traditionally went, the lichens are perhaps not as abundant? DAVID SWANSON: You know, that -- that’s -- that’s quite likely. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: You know, and that’s not necessarily a -- a -- an unnatural process. You know, caribou -- you know, lichens grow slowly, and they can be depleted, and they take decades to grow back. Um, it’s not like grass that’ll grow back next year.

And so, I think caribou always had to shift their wintering grounds in order to deal with the fact that lichens are being depleted. And so, that’s, I think that’s kind of the way I look at this process now, is that they -- I -- I don’t have data.

I think I’ve seen some data to show that other places that they’ve wintered are maybe getting depleted in lichens. Fires can deplete lichens, too, right? LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: But, for whatever reason, there’s gorgeous lichens in Bering Land Bridge National Preserve, and it’s just not surprising that the caribou would find them and spend the winter in the park eating them.

LESLIE MCCARTNEY: Right. There again, another -- another longitudinal study, you know, to -- over time to see where caribou have actually been over time, connected with food. DAVID SWANSON: Yeah. LESLIE MCCARTNEY: Right? 'Cause it’s a natural process. They -- they just -- they go where the food is.

DAVID SWANSON: Right. And we -- you know, and we do have a caribou vital sign, and it’s an interagency project where we have caribou collared, and that’s -- that’s one that one of my colleagues works on.

And they are keenly interested in where the caribou go, and they have done a lot of unusual things lately. And caribou always are doing unusual things and stumping people. And going in unexpected places.

And anyway, that’s happening now, and one of the effects is that they are eating lichens in the park, and I think -- you know, I mean, I think we look at it as, you know, that’s -- that’s the way it should be. You know, is that we -- we should have -- we should have luxuriant lichens, at least in places, and we should have caribou eating them, and that’s what’s been going on.

And so, sometimes then when you come in the next summer, you’ll see places where you can see that the lichens have been -- have been cropped off.

LESLIE MCCARTNEY: Right. Is it -- is there a -- I don’t know much about lichens other than that they make a really good dye for wool. Um, are there various kinds of lichens? Are the caribou just interested in one particular kind, or are there multiple kinds of lichens?

DAVID SWANSON: So there are many kinds of lichens. Yeah, as you -- I’m sure you anticipated that answer. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And there are, um, you know, in our environment, mosses and lichens rival the vascular plants in their numbers of species, right? The diversity is just astounding. And uh, they are -- the diversity is truly amazing.

But it’s true that caribou really only exploit a few of them. Um, you know, there’s a few real favorite ones that they -- that form the thick mats. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And they’re, of course, the ones that people call reindeer moss, or I prefer to call them reindeer lichens because they’re not mosses. LESLIE MCCARTNEY: Right.

DAVID SWANSON: But that -- those, of course, that’s a group. There’s actually several species that are so-called reindeer moss or reindeer lichens.

And -- and in addition to the classic reindeer lichens, there are some other ones that they eat. But they really are, um -- You know, I don’t know, there’s probably, you know, six or eight species that are really the ones that they like the best, and that are the ones that they can get to also.

You know, because you can imagine, how lichens have to be -- the caribou have to paw through the snow to get ’em, and you can imagine that they have to be -- and then they have to be able to bite something off, right? And so, they have to be fairly thick and dense to be really worth all that work. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And so, there are quite a few lichens that, you know, either are, you know, prostrate to the ground or, um, you know, kind of scattered around or very delicate or something, and for whatever reason just aren’t something that a caribou can get a mouthful of.

And so, it’s just -- there are these certain ones that really do form nice stands that a caribou can almost -- almost graze them like -- like you might imagine a, like a sheep, grazing grass. I mean, they actually are -- they can be several inches high and dense, and the caribou can actually just eat them like they would eat grass, although they have the extra work of having to paw through the snow to find them.

And so, in the next summer when you’re there sampling the vegetation, you notice that there are -- there tend to be these circular patches of where the lichens are obviously been, um, pawed at and -- and dug up and eaten and that kind of thing. And oftentimes, surrounded by places where the caribou didn’t, you know, find them.

'Cause they don’t -- they don’t graze it. At least, you know, typically caribou, if they’re unconfined and uh, you know, and this is just a one-time deal, they’re going to come through an area and make these craters that leave -- and you can see where the lichens are eaten. But then next door, there’ll be lichens that are still intact, and hopefully the caribou can come back and eat some more there next year.

But, eventually, since they grow back so slowly, it’s not uncommon for them to find most of the lichens that aren’t -- that at least aren’t too deep in snow drifts. That’s one thing is, that if you have, um, if you have deep snow drifts, then sometimes the caribou just can’t get to them. LESLIE MCCARTNEY: Um-hm.

DAVID SWANSON: And um, and so then, eventually they’ll have to abandon an area because most of what’s edible is gone, you know. LESLIE MCCARTNEY: Hm. Interesting. DAVID SWANSON: Yeah. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: And -- and we are concerned that in the future, with shrub expansion, that they might, um -- you know, the shrubs can suppress lichens, and they -- and we expect that to happen.

Uh, we expect that it’s probably happening already to some degree, because, you know, shrubs really kinda -- they can’t handle a lot of leaf litter fall. They need to be kinda out in the open. They can handle some, but not a lot.

And so, um, but, you know, as I was saying that we haven’t documented a huge amount of shrub increase yet, and so that is something that was mostly kind of a concern for the future. LESLIE MCCARTNEY: Hm. DAVID SWANSON: At the moment, our lichens are looking pretty good. LESLIE MCCARTNEY: Are good?

DAVID SWANSON: Yeah. And we, you know, and -- and there were a lot of -- there were some really big fires in, you know, in the -- in this area back, you know, in the previous century, and the lichens have recovered nicely from those.

But, you know, there’s always the chance that we could have a -- almost anywhere except in the lava beds where there’s not enough fuel. LESLIE MCCARTNEY: Yeah. DAVID SWANSON: You know, we could -- we could get some fires.

And last summer, actually, flying around, um, we saw more than -- more than a few lightning-strike areas on the tundra where there was a little patch, um, that it had burned and then it had gone out. LESLIE MCCARTNEY: Hm.

DAVID SWANSON: And so, there had been apparently enough rain or it was just wet enough that that lightning strike didn’t manage to turn into a big fire. But um, I don’t expect it’ll always be that way. LESLIE MCCARTNEY: Yeah.

DAVID SWANSON: Uh, ’cause, you know, we do have -- I don’t know. It’s hard to know where the summers are gonna go because it’s -- like last summer, um, you know, it was very hot and dry for a while, but then it rained a lot. LESLIE MCCARTNEY: Right.

DAVID SWANSON: And uh -- and so that -- you just -- it’s hard to tell. Around here, too. LESLIE MCCARTNEY: Yeah. DAVID SWANSON: You know, it’s -- we’ve had a lot of big fire years, and then we’ve also had tremendous amount of rain, too. LESLIE MCCARTNEY: A lot of rain years.

DAVID SWANSON: And so it’s really hard, I think, for us to know how that balance is going to get tipped in the future.

LESLIE MCCARTNEY: Mm, interesting. Yeah. Um, we’ll just look down the list and see if there was anything else, then, Dave, that you made notes on at all. Um -- DAVID SWANSON: I think I’ve -- I’ve talked a lot.

LESLIE MCCARTNEY: It’s wonderful. You’ve really captured -- DAVID SWANSON: I’m running out of things that I know, so. LESLIE MCCARTNEY: -- captured a lot of things that we were really curious about, so it’s been really wonderful. DAVID SWANSON: Oh, good.

LESLIE MCCARTNEY: And you do have the best job in the -- in the Park Service. DAVID SWANSON: Oh, it's -- LESLIE MCCARTNEY: I think. DAVID SWANSON: Yeah. I don’t think there’s any doubt about that. LESLIE MCCARTNEY: Well, thank you so much for taking time today to come in. Thank you. DAVID SWANSON: All right. Well, thanks for having me. LESLIE MCCARTNEY: Ok.