How climate change impacts the Crown of the Continent
(This is the second in a series of Q & A's on the Crown of the Continent, a 10-million-acre expanse of land in northern Montana and southern Canada. Dan Fagre is a research ecologist at the U.S. Geological Survey who has spent 15 years working to understand how climate change will affect mountain ecosystems like those found in the Crown. To learn more about this wild place and how Earthjustice is working to protect it, check out our Crown web feature.)
EJ: What changes have you seen in Glacier National Park since you first started?
DF: I was hired to start the climate change research program here in 1991. One of the first things that we did is look at Glacier National Park, specifically Grinnell Glacier, to monitor the impacts of climate change through time. So I've sort of had an intimate relationship with Grinnell in particular, and I've seen just without pulling out photographs or maps each year the changes that occur there. 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.
EJ: How is a warmer climate impacting native species of the Crown?
DF: 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, "Nature abhors a vacuum." There's going to be some species that enjoy the new, warmer climate. For instance, we may have more lodge pole pine, but fewer hemlock and cedar forests. We may also have more insect outbreaks. 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 native species adapted to the colder waters. It's also very likely that our mule deer and white-tailed deer will do better in the new environments that we create. Anecdotally, we've also 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.
However, when anything affects one species you're going to have a cascading effect on other species. As a prey species either increases 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. The lynx is what is often called a snow-dependent carnivore. Many of its adaptations are not really an advantage unless you have that snow. Without it, other predators like coyotes can out-compete them. So when you have snow packs declining, this is obviously not going to bode well for snow-dependent carnivores.
Grinnell Glacier, which was named by George Bird Grinnell, an American naturalist widely credited as the father of Glacier National Park. Photo © Gene Sentz
EJ: Many species in the Crown are currently endangered. How is climate change affecting them?
DF: We often think of climate change as one of a stress complex. You have multiple stressors. Some species are already under stress from landscape development and habitat fragmentation. 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 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 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.
Warming in the Crown has been two to three times the global average. But this is not unique to our area, per se. Many mountain areas have warmed up faster than lowland areas. With respect to extreme values, we found that the number of days over 90 degrees Fahrenheit occurred two to three times more in our area versus other areas. We chose 90 degrees because it's a threshold for physiological stress for lots of plants and animals. Plants will start conserving water, close up their stomata and so forth. Animals will go into shaded areas or underground to get rid of the heat. For many alpine and mountain species that have adaptations for extreme cold, once you start getting these days over 90 degrees, 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.
EJ: What steps is the USGS taking to address climate change in the Crown?
DF: The scientific consensus is that we are already committed to a certain amount of warming and that adaptation is the smart thing we should be doing. One of the roles that the USGS plays is to try to figure out what we need to adapt to. Climate impacts research documents not only what's already happened, but also tries to figure out what monitoring we need to do for the future because in many cases you need to have several 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 that lives up in the high alpine areas. When concerns about it first surfaced we didn't have any population data, so you couldn't really see any population trends over time. And that's a case 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.
Unfortunately, nobody on the planet can afford to get baseline data on everything, so you have to choose some representative phenomena. One of the advantages that we have with trees is that they're very long-lived and that they record climate information. So, there's been quite a lot of interest in using trees as climate history books to look back in time and see what patterns there have been in the past and also see how the ecosystem adapted to those changes. 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.