Dan Fagre is a research ecologist at
the Northern Rocky Mountain Science Center
of the United States Geological Survey.
Glaciers integrate fluctuations in snow over time, providing a barometer of the kinds of changes that are occurring throughout the ecosystem.
The effects of warming are magnified by two to three times in the Crown ecosystem.
When a climate warms, there are winners and losers because species are adapted to the ecosystem and the climate regime over long periods of time—and when anything affects one species, there will be a cascading effect on others.
There are two dimensions of how climate change affects things: when it happens and how much it warms.
Dan Fagre is a research ecologist at the Northern Rocky Mountain Science Center of the United States Geological Survey. He is studying climate change's effects on mountain ecosystems such as Glacier National Park, the cornerstone of the Crown of the Continent ecosystem and a major focus of Earthjustice's litigation.
Based on decades-long research, Fagre predicts that Glacier National Park will lose all of its namesake glaciers by 2020. Fagre spoke with associate editor Jessica Knoblauch in March of 2011.
Dan Fagre: Well, I was hired to start the climate change research program here in 1991. And one of the first things that we did was we went up and looked at Grinnell Glacier and we had written a proposal to use the glaciers of Glacier National Park to monitor the impacts of climate change through time. And I've seen each year the changes that occur there. And now when we go up to monitor the size of the glacier we walk across rocks and land that has not been exposed to the atmosphere for probably 500 years because the glacier is retreating. So, in a sense, we're kind of the first people to walk on that in many hundreds of years since it was covered by ice.
Jessica: Why focus on glaciers for climate change research?
Dan: We use glaciers in part as a barometer of the kinds of changes that are occurring throughout the ecosystem. Glaciers are more of a steady indicator because they integrate fluctuations in snow over time and so that makes it a more reliable indicator of long term trends. So if a glacier is retreating or it's advancing, it indicates trends over many, many years, not just year-to-year annual variation. So that gives us a good measure of the long-term change.
Jessica: When glaciers lose lots of ice over time, does that impact nearby rivers and streams?
Dan: Glaciers do provide a direct impact to aquatic ecosystems. The melting of those provides critical water supply to our streams in the upper elevations particularly, and that is where many of our fairly unique alpine aquatic biota live. So they not only need the water, it has to be very, very cold water because they're alpine-adapted species. And so, the glaciers kind of provide a buffer, a reserve, a lifeline, whatever term you want to use, but without them there those streams would either be too warm or would dry up entirely. And so the glaciers are acting as kind of a critical buffer against late summer heat for a lot of these species.
Jessica: Are there any examples of a warmer climate actually benefitting species?
Dan: When a climate warms, there are winners and losers because species are adapted to the ecosystem and the climate regime over long periods of time. You know the old saying about nature abhors a vacuum. There's going to be something that enjoys the new, warmer climate. So, we may have more lodge pole pine, for instance, and fewer hemlock and cedar forests. Certainly we have had changes in the aquatic biota as the streams warm up, certain fish and in some cases invasive fish species that aren't native to the area do better than the native species that are adapted to the colder waters.
Similarly there have been lots of questions about how pika will be able to respond to warmer temperatures and there's been some speculation about mountain goats and so forth. But it's very likely that our mule deer and white-tailed deer will do better in the new environments that we create. And, anecdotally we've been seeing more raccoons and foxes in Glacier National Park then have been recorded in the past. So, they seem to be finding the warming climate and the responses of the ecosystem to their advantage.
When anything affects one species, you're going to have a cascading effect on others. And so, as a prey species either increases in abundance or decreases in abundance, obviously there are predators directly linked to that. Some predators are flexible enough to find other prey and others are more directly linked because of their adaptations to a certain prey base. And the lynx is an example where it has a big advantage in the snow with its huge paws, and so it's what is often called a snow-dependent carnivore. Many of its adaptations are not really an advantage unless you've got that snow.
And similarly, species like the wolverine are quite dependent on snow pack for denning, in particular, although they have lots of other adaptations to cold weather and snow that give them an advantage over other smaller carnivores. So there's less snow on the ground on an annual basis than there used to be and there's less of it. These are obviously not going to bode well for snow-dependent carnivores. For many alpine and mountain species that have adaptations for extreme cold, well that works great as long as it's cold but once it gets warm, once you start getting these days over 90, it's like they can't take off an overcoat. They can't go inside and turn on the air conditioning, so they do experience some stress in many cases if they can't change their behavior. But this is not unique to our area, per se. Many mountain areas over the globe have warmed up faster than lowland areas.
Jessica: So how will climate change affect species that are already endangered from other environmental stressors like habitat destruction
Dan: We often think of climate change as one of a stress complex. For instance, species that need a lot of room to roam are more vulnerable because as they have more landscape development around places like the park or wilderness areas, it's harder to cross over developed land that's been fragmented by roads and factories and farm land and so forth. And then if you add climate change on top of that, the two stresses might do to that population what one didn't.
In other words, it's sort of like an immune system. You can handle a certain amount of germs and everything on a daily basis, but once you get run down, all of a sudden you get sick because your immune system has dropped. Well, in a sort of parallel way, that's what seems to be happening for many parts of the West at least where something like air pollution and landscape fragmentation doesn't have a big effect, but then something like climate change can be the one that puts it over the top, that's basically a tipping point.
And so in those cases, it's often a focus of managers to be looking at one threat or one stress on a species, like our bull trout, for instance, and some other stressor comes from behind in the background that they're not really thinking about and actually provides the final little push to create a situation where that species is now suddenly very vulnerable.
Jessica: As you know, Glacier National Park is part of the Crown of the Continent ecosystem, which is a huge expanse of land that has a lot of microclimates. Are there certain areas within the Crown that are more affected by climate change than others?
Dan: Yes, I think our highest elevations are probably being affected relatively more than the lower valley locations, for instance. Because snow melt is such a key trigger for lots of ecosystem processes, when that occurs earlier in the year and the timing of that changes it really affects a lot of those organisms a lot.
An example is that we have a relatively rare alpine poppy, a small flower that mostly grows beneath snow banks and glaciers and is dependent on the moisture from that. And if the snow melt occurs earlier in the year and it warms up to much, first of all the timing of the growth is not keyed to the season like seasonal light and other things like it used to be. And secondly, it may run out of moisture before it completes its lifecycle for the year. And so, those kinds of timing issues of growth and so forth, that's as critical as how much change there is.
So, sometimes just a shift in when it's occurring can have as much ecological effect as the total magnitude of the warming. So, a 90 degree day in August is not going to cause as much stress to these organisms as a 90 degree day in May because it's the wrong time of year for that heat to be there and it basically messes up their rhythms. And so that's something else that we need to keep in mind when we look at climate change effects on mountain ecosystems.
Jessica: What about snow avalanches? Has a changing climate affected those at all?
Dan: Well, we don't know. We are speculating that we will have some significant changes in our snow avalanche dynamics. You typically have what we call dry slab avalanches in the winter. These are deep snowpack so that the snow is cold and so forth. And you get unstable layers deep in the snowpack so when the avalanche goes it all slides as one big unit and its dry breaks up. So it's a particular kind of avalanche. And that's important for keeping some of these snow corridors open continuously so forests don't invade. That eventually winds up being important for species like grizzly bears and others that forage in these avalanche paths where the trees are continually scoured out and you have much more nutritious vegetation growing in those paths.
So there is a complicated link between how much snow we get, what kind of snow it is, landscape features like snow avalanche paths and basically the ecology of birds, bees and bears.
That's kind of one aspect of it. The issue is that as we move to a warmer climate, we're seeing unusual things that are big snow storms followed by rain, for instance. And you have a rain on snow event and it destabilizes snow in a different way. And it causes many of these areas to slide in the winter in a wet form that's unusual. You might get more entrainment of dirt, soil, boulders and debris with these wet avalanches that are increasing in magnitude. And, as they dump all of that into streams, then you start changing the nutrient quality of those streams and the turbidity and all these other kinds of things.
Jessica: Since climate change affects are obviously already happening, what are we doing to adapt?
Dan: I think that the scientific consensus is that we are already committed to a certain amount warming and that adaptation is of course the smart thing we should be doing. One of the roles that the USGS plays is to try to figure out what you need to adapt too. We continue to do what's called climate impacts research, which is basically not only documenting what's already happened in the warming that's already occurred and the changes we've already seen, but also trying to figure out what information managers are going to need in the future because in many cases you need to have five, 10, 20 years of data to really be able to know what's going on and make management decisions.
A case in point is the pika. The pika is a low rock rabbit, a cute little organism that lives up in the high alpine areas and when the concerns about it first surfaced we didn't have any population data. We knew their biology and so forth, but we didn't know how many we had and where. So you couldn't really see any trends because you had no population data. And that's a case in point where a much better evaluation could have been made if those data had been collected, but because it wasn't a concern in the past nobody had thought to do that. So one of the responsibilities that we as scientists have is to try to figure out what should we be looking at and monitoring now because this information will be needed in the future.
Unfortunately, nobody on the planet can afford to get baseline data on everything. You have to choose some representative phenomena, like monitoring snow pack in streams and some organisms. And that's what a lot of work is being devoted to now is trying to get information on what we can. Luckily one of the advantages that we have with trees is that they're very long lived and that they record climate information. And so there's been quite a lot of interest in using trees as basically climate history books to look back in time and see what kinds of patterns there have been in the past and also see how the ecosystem adapted to those. And so these sort of analogs are useful for looking at the future.
An example, for instance, is that in the 1500s and 1600s when we were in the beginnings of the so-called Little Ice Age, a lot of our cedar and hemlock trees established then because it was cooler and wetter. Now, when it's warmer and dryer, these trees are still persisting, but they probably couldn't get started here now. In other words, the climate envelope for them has changed, has moved on. And yet they persist here simply because they're long-lived organisms.
So when we have a major forest fire and it happens to wipe out those trees, we probably won't get them back because the climate is no longer suited for them. And those are the kinds of things you can see how the ecosystem is responding over long time periods and get a much better sense of how it will probably respond in the future. There are a lot of lessons from the past that are germane to looking in the future when you consider a mountain ecosystem like what Glacier National Park encompasses.
Jessica: Well, that's all of the questions that I have for today. Dan, thank you so much for your time.
Dan Fagre is a U.S. Geological Survey ecologist who has been studying glaciers in Glacier National Park for more than a decade. To learn more about our work to protect endangered species and habitats in rapidly changing areas like the Crown of the Continent, which includes Glacier National Park, check out earthjustice.org/crown. And to hear more Down to Earth interviews with environmental experts, check out earthjustice.org/downtoearth.
Dan Fagre spoke with Down to Earth in March 2011.
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