90.9 WBUR - Boston's NPR news station
Top Stories:
PLEDGE NOW
Here and Now with Robin Young
Public radio's live
midday news program
With sponsorship from
Mathworks - Accelerating the pace of engineering and science
Accelerating the pace
of engineering and science
Friday, January 31, 2014

Monarch Butterfly Population Continues Alarming Drop

Two Monarch butterflies on their epic journey (SK Films)

Two Monarch butterflies on their epic journey (SK Films)

This week, reports out of Mexico, where monarch butterflies make their winter migration from the U.S. and Canada, show that the number of butterflies has dropped for the third year in a row.

Chip Taylor, founder of of Monarch Watch, joins Here & Now’s Jeremy Hobson to discuss the reasons behind the drop, including extreme weather conditions in both 2012 and 2013, and the use of herbicides.

Interview Highlights: Chip Taylor

Why the monarchs are disappearing

“Over 30 percent of the monarch habitat has been lost since 2006, and this is due to a couple of things, one of which is the development of Roundup Ready corn and soybeans, which has allowed the farmers to spray glycosphate on those fields to control weeds, because the plants themselves have been genetically engineered to resist that particular herbicide. Well, previous to the use of those types of plants and the glycosphate, the corn and soybean fields used to contain milkweeds — at a small level, but it turned out that a survey done in 2000 showed that that was the most productive habitat for monarch butterflies. Now, it’s gone.”

The impact of weather on monarch populations

“We’ve had some unusual events in the last three years. To really be an effective population, to really reproduce well, the butterflies that come out of Texas in May and early June have to arrive at the summer breeding ground site — that’s the northern part of the U.S. and southern Canada — at the right time. So there’s about a three-day period there, and they have to arrive in the middle of that period, and they have to arrive in good numbers.”

“There has never been a March in the history of recorded temperatures in the United States quite like the March of 2012. It was very, very, very hot. And this was followed by a hot spring, and it was followed by an extraordinarily hot summer, so overall, 2012 was a very hot year, and it did not bode well for the butterflies. It really put them down. They spread too far north too soon.”

On what would happen if the monarchs vanished

“One of the things I try to tell people is it’s not just monarchs. Monarchs are simply a flagship species for everything else that’s happening out there. If you look at where monarchs live, they live in habitats that are kind of marginal, but those marginal habitats support most of our pollinators. Those marginal habitats support a lot of small mammals and ground-nesting birds, and if we lose the monarchs, it means we’re going to lose all those things. And the one thing people perhaps do not grasp is that it’s the pollinators that keep everything knitted together out there. I mean, there’s a fabric of life out there maintains these ecosystems, and it’s the pollinators that are critical here. They pollinate about 70 percent of that vegetation. If we don’t have the pollinators, that means we’re going to be losing a lot of plants, then you lose a lot of organisms that are dependent on specific plants and so on and so forth. You know, my plea is that we have to maintain these habitats, not only for monarch butterflies, but for everything else, because it’s really in our best interest to do so.”

More On Monarch Butterflies

Guest

Transcript

JEREMY HOBSON, HOST:

This is HERE AND NOW. And now for some alarming news about monarch butterflies. This week, the World Wildlife Federation Chip and the Mexican government reported that the migrating population of monarch butterflies coming from the U.S. and Canada is continuing to shrink. The acreage that butterflies occupy in their winter home in the Mexican mountains has dropped 56 percent from last year, and that's a continuation of a decline seen over the past several years.

Joining us now from Lawrence, Kansas, is Chip Taylor. He's founder of Monarch Watch and professor of ecology and evolutionary biology at the University of Kansas. Professor Taylor, welcome back to HERE AND NOW.

CHIP TAYLOR: Nice to be with you, Jeremy.

HOBSON: So this is the third year that we're seeing big drops in the numbers of monarch butterflies. What's going on? How serious is this?

TAYLOR: Well, it can be quite serious. Anytime a population like this gets to be quite small, it's subject to real danger if there are catastrophic events. If we have winter storms in Mexico that further devastate the population, drive the numbers down even further, and we've seen that in the past, that would be many years for the population to recover.

HOBSON: Well, and you mentioned the weather in Mexico. Of course a lot of people also looking at the weather in the United States, where they come during the warmer months. What has happened with the weather and the climate on the migratory route north?

TAYLOR: Well, we've had some unusual events in the last three years. To really be an effective population, to really reproduce well, the butterflies that come out of Texas in May and early June have to arrive at the summer breeding grounds, that's the northern part of the U.S. and southern Canada, at the right time. So there's about a 40-day period there, and they have to arrive in the middle of that period, and they have to arrive in good numbers.

HOBSON: And they're not?

TAYLOR: Well, that's what didn't happy in 2012, and it didn't happen in 2013. So 2012 was probably the most unusual year that we've seen in a long time in the United States. As you may recall, as your listeners may recall, there has never been a March in the history of recorded temperatures in the United States quite like the March of 2012.

It was very, very, very hot. And then this was followed by a hot spring, and it was followed by an extraordinarily hot summer. So overall, 2012 was a very hot year, and it did not bode well for the butterflies. It really put them down. They spread too far north too soon. So instead of arriving in the middle of that 40-day period that I was telling you about, nearly all of them arrived at the beginning of that 40-day period.

Now what would be the consequences of that? Well, they could be way ahead of the milkweed, which is developing, or they could just simply overshoot their target, which is the milkweed in the north. And we had - that particular year we had monarchs showing up all over the prairie provinces in numbers that had never been seen before, in places where there were no milkweed.

So it really looked like they got too far north too soon. Then it was followed by a hot summer, and the population crashed.

HOBSON: Well, you mentioned milkweed. A lot of people are saying that one of the problems is that we've replaced so much land that used to have milkweed on it with other things, with genetically modified crops, with ethanol production, that there's just no place for them to go.

TAYLOR: Over 30 percent of the monarch habitat has been lost since 2006, and this is due to a couple of things, one of which is the development of Roundup Ready corn and soybeans, which has allowed the growers to spray glycosphate on those fields to control weeds because the plants themselves have been genetically engineered to resist that particular herbicide.

Well, previous to the use of those types of plants and the glycosphate, the corn and soybean fields used to contain milkweeds, at a small level, but it turned out that a survey done in 2000 showed that that was the most productive habitat for monarch butterflies. Now, it's gone. I mean, you - I've challenged people to go out and find pictures of milkweed in cornfields, and I haven't seen milkweed in cornfields in 10 years. I keep looking.

HOBSON: Well, you know, you mentioned corn. I grew up in the middle of the corn fields in Central Illinois, and I remember one year that the monarch butterflies came and stopped somewhere along their migration, right about a block away from my house, and they were covering all of the trees right there. And we went down to see them, and it was just an astonishing sight. Is that something that we wouldn't be able to see these days at certain points that far north?

TAYLOR: Well, there is an organization called Journey North, which has a program in the fall called Journey South, in which they track all of the clusters such as you're describing. And the numbers of clusters that are seen now is way down compared to what it has been in the past. So these numbers are diminishing. These observations such as the one you just talked about are becoming really scarce.

HOBSON: Chip Taylor, how do these monarchs figure out where they're supposed to go?

TAYLOR: That's the big scientific question, and there are quite a few hints that are coming out from some excellent research that is being done by Steven Reppert(ph) and his colleagues at the University of Massachusetts, and one of which is that the butterflies are using sun compass orientation. They have a biological clock on their antennae that communicates with a biological clock in the brain, and that has the effect of maintaining them on course.

What's coming up next is to try to determine how they set their course. By that I mean butterflies moving through my part of Kansas are going at about 210 degrees, but if you look over at what's happening just north of Atlanta, they're going roughly about 260 degrees. And this is very consistent. It's over years and many different observations, and we're looking at butterflies that are moving without wind, and they're simply using some sort of environmental information to pick a particular heading.

So I think that we're going to hear a lot more about this in the coming years because I think the methods are coming to the fore that will allow the researchers to answer this question.

HOBSON: Well, back to the problem at hand, and that is the declining numbers of these butterflies, you mentioned the hot weather in 2012. It has been a very cold winter. Is that a good thing? Is that something that may lead us to see more monarch butterflies next year?

TAYLOR: Well, the winter temperatures don't seem to have an effect on the population, although they may have an effect on some of the predators and parasites that affect the monarch population. So by and large I'd want to see really harsh winters because I think it would knock down a lot of the predators and parasites, parasitoids, that these things are affected by.

HOBSON: If the worst-case scenario happens, and that is that the migration vanishes, what kind of implications does that have on other organisms?

TAYLOR: Well, one of the things I try to tell people is that it's not just monarchs. I mean, monarchs are simply a flagship species for everything else that's happening out there. If you look at where monarchs live, they live in habitats that are kind of marginal, but those marginal habitats support most of our pollinators.

Those marginal habitats support a lot of small mammals and ground-nesting birds, and if we lose the monarchs, it means we're going to lose all those things. And the one thing that people perhaps do not grasp is that it's the pollinators that keep everything knitted together out there. I mean, there's a fabric of life out there maintains these ecosystems, and it's the pollinators that are critical here.

They pollinate about 70 percent of that vegetation. If we don't have the pollinators, that means we're going to be losing a lot of plants, then you lose a lot of organisms that are dependent on specific plants and so on and so forth. So, you know, my plea is that we have to maintain these habitats not only for monarch butterflies but for everything else because it's really in our best interest to do so.

HOBSON: Chip Taylor is the founder of Monarch Watch. He's also a professor of ecology and evolutionary biology at the University of Kansas. Chip Taylor, thanks so much.

TAYLOR: Hey Jeremy, very nice to talk to you. Thanks for having me on.

HOBSON: And believe it or not, there may be something that you can do to help sustain the population of monarch butterflies. You can find out how at hereandnow.org. You're listening to HERE AND NOW. Transcript provided by NPR, Copyright NPR.


Please follow our community rules when engaging in comment discussion on this site.
Robin and Jeremy

Robin Young and Jeremy Hobson host Here & Now, a live two-hour production of NPR and WBUR Boston.

September 26 4 Comments

Dean Of Boston Sports Journalism Celebrates 42 Years On The Job

Here & Now's Robin Young visits the most-beloved sportscaster you've never heard of: Jonny Miller.

September 26 4 Comments

Severe Black Lung Rebounds Among Miners

The most severe kind of black lung almost disappeared from Appalachia after regulations went into effect. But now it is on the rise again.

September 25 3 Comments

U.S. Ebola Effort Focuses On Treatment Facilities, Training

The White House is sending 3,000 U.S. troops to Monrovia, Liberia, to help assist in the effort to contain the Ebola crisis in the region.

September 25 4 Comments

Seattle To Fine Residents For Trashing Food Waste

A new measure in Seattle will fine residents if more than 10 percent of their garbage is food waste in an attempt to curb waste going to landfills.