Protecting monarch butterflies’ winter home could mean moving hundreds of trees

From Nature

Researchers are trying to shift Mexico’s oyamel firs to higher elevations to help them weather warming temperatures.

Monarch’s at Pacific Grove, California. Credit: ctm

Monarch butterflies alight on a tree in their wintering grounds in Mexico.Credit: JHVEPhoto/Alamy

To save dwindling populations of Eastern monarch butterflies, researchers in Mexico are trying something controversial: moving hundreds of fir trees 400 metres up a mountain. Their goal is to help the trees, which serve as winter habitat for the migratory butterflies, keep up with the changing climate.

Forest geneticist Cuauhtémoc Sáenz-Romero at the Michoacan University of Saint Nicholas of Hidalgo (UMSNH) in Morelia, Mexico, has been relocating oyamel firs (Abies religiosa) in the Monarch Butterfly Biosphere Reserve, about 100 kilometres northwest of Mexico City, for the past 3 years. A study reporting the results of the experiment is currently under review at a scientific journal.

For nearly two decades, the idea of ‘assisted migration’ — moving species to new areas to rescue them from rising temperatures — has stirred controversy among ecologists. Opponents worry that species introduced into other regions could spread so much that they threaten organisms already living there1.

But in the case of the oyamel fir trees, some scientists think the risk is worth it. “This is an example of a good experiment,” says Sally Aitken, a forest ecologist at the University of British Columbia in Vancouver, Canada.

Fall of a monarchy

Over the past 20 years, the number of monarch butterflies (Danaus plexippus) in North America has dropped by more than 80%, according to the Center for Biological Diversity, a non-profit group in Tucson, Arizona.

The decline has affected both the Eastern monarch population, which migrates from the northern and central United States and southern Canada to Mexico each autumn, and the smaller, Western monarch population, which migrates across western US states and winters in coastal California. In June, US officials are expected to announce whether these two populations will be protected under the Endangered Species Act.

Rising temperatures and habitat destruction at the butterflies’ breeding sites in the United States and Canada are the major drivers of monarch declines, says Karen Oberhauser, a conservation biologist at the University of Wisconsin–Madison.

Extreme climate events threaten the Eastern monarch butterfly’s habitats at their wintering sites in Mexico, Oberhauser says. In 2016, for example, a severe storm damaged thousands of fir trees in the mountains of central Mexico. The loss of habitat, followed by freezing temperatures, killed 31–38%2 of the monarchs.

And Sáenz-Romero has estimated that rising temperatures will shrink the habitat suited to oyamel fir trees in Mexico nearly 70% between 2025 and 20353.

Read the full story here

HT/Michael M

84 thoughts on “Protecting monarch butterflies’ winter home could mean moving hundreds of trees

  1. I really have to wonder how all these species managed to survive before modern man came along to help them out.

    • yep, the big (recent) freeze damaged the habitat and resulted in 1/3 butterfly mortality.

      So, let’s move the trees up the hill into the colder temps to help the butterfly population.

      I’m missing something; if I was a butterfly botanist (and getting paid to do something … anything) it would probably be completely crystal clear.

      • Alexandria Ocasio-Cortez has got a better idea: We build a lot of railways so we can put the trees on a train, and then move them up and down the mountain at will to suit the butterfly’s needs, depending on the weather.
        The power of lateral thinking.

        • “Alexandria Ocasio-Cortez has got a better idea.”

          We must act quickly! We only have twelve years left.

  2. Reforestation in the north eastern US may be plying a major role. Marginal farms etc are now treed squeezing out space for the milkweed the monarchs primary food and egg laying plant.

  3. A common weather event (storm) knocked down a bunch of trees normally used by the butterflies. Following that came another common weather event (cold snap). These two events led to the deaths of 31 to 38 percent of the butterflies.

    It sure sounds like global warming caused their numbers to decline. Yep, that’s the ticket.

  4. Freezing temperatures? Yeah, sounds consistent with a warming globe. Must be CAGW. Settled science and all…

    • This and previous comments point to studies that identify causes, other than a generally warming world, for butterfly declines. Why didn’t this report identify them?

      This is a more general problem. Often a big study will come out, only to have people on WUWT identify many issues not considered in the study.

      It seem that experts either don’t know of or simply ignore confounding information. With many such examples, I am more and more distrustful of academic reports. Scientific corruption?

      • In the major science journals “Science” and “Nature” there is a talk of a reproducibility crisis in academic research. Most recently Harvard retracted 30 papers of a researcher and cancel a human stem cell trial based on a alleged fraud. Need I say more?

      • I have this feeling that education does NOT equate with intelligence after reading most of the parlous “studies” I see at WUWT

        many years ago i read? something like…its easier to fool an educated person than a caveman
        back then i was puzzled
        as I age I realise how true that is

  5. This story is a set-up — from a Nature news article. Monarch butterflies are fascinating and only understood on an observational basis. Nothing is understood about why and how the two populations of Monarchs in the US migrate to their wintering spots — one on the California coast, and the larger population to Mexico.

    In Mexico, the monarchs over-winter in central Mexico in a stand of oyamel fir trees. The Western monarchs overwinter in other trees on the California coast, including eucalyptus trees.

    The most recent blow to Eastern Monarchs was a severe storm in Central Mexico in 2016, which downed trees and was followed by a freeze that killed many (30-38%) monarchs.

    Despite the known threat of freezing temperature, which recur every few years and result in the deaths of many monarchs — scientists in Mexico have attempted to plant oyamel firs further up the slopes in the biopreserve to protect the monarchs from “rising temperatures” — when it is freezing temperatures that have historically killed monarchs there.

    If this monarch-mania keeps up, I’ll be forced to provide a full essay about them — there is so much misinformation being bandied about that the needed actions will be subsumed in some foolish effort to “save them from global warming”.

  6. Unprecedented cold killed 31-38 percent of the monarchs, so they are going to move their habitat to a higher altitude where they are likely to be exposed to even colder temperatures. Sounds like a good plan from eco loons.

  7. If half a degree of warming was going to kill of the Monarch butterflies, they would have died out millions of years ago.

    • Note that they fly across an entire continent, twice every year, with a lot of that time in torridly hot weather, but they think it might be too warm for them in Winter.
      They go there because it is hot! Sometimes anyway. Or at least not freezing…more than one or twice every few years. Usually.
      Also seems likely that this is where they evolved, and have spread a little further at a time over many years.
      Nowadays, they spend a lot of time in places that were under miles of ice for over a hundred thousand years at a time.
      Warmista jackassery is seemingly infinite, and knowledge of past events, of Earth history, of the resilience of living things and systems…well, that is very nearly non-existent. AFAICT.

    • With such limited resources as we have today, we have to recycle what we’ve got. That means we must move the trees.
      What do you mean by “plant more”?

  8. Freezing temps caused a one off decline in butterfly numbers…so they must be saved from global warming. Otherwise disruption of their habitat is causing a general decline…so lets move all the trees to a higher location where they will probably not survive very well as they are not there by the will of nature now…and the butterflies are going to be even more exposed to freezing temps should another such storm occur.
    These people will destroy the planet….have you seen the maniacs are talking about lowering CO2 with machines? And want to blot out the sun with reflective particles? Do the worlds population get a vote on this? And will one of the voter options be to have all these people shot into the sun by rocket? And can I push the ignition button?

    • That cold snap and die off were not one off events, not by a longshot.
      I can recall back in the 1980s and 1990s at least two separate occasions when those groves of trees froze, from reading stories about it in the newspapers. Of course, each time it was treated as an unprecedented event, and questions were asked about if they would all die.
      How cold does anyone suppose it got down there during the LIA, and for that matter, the big ice ages…the glacial advance periods?
      BTW…what warming are they saving them from?
      They risk killing them by messing around with their habitat.

    • Thank you for voicing my concern. I would not mind at all if they were just tree planting. However, moving the trees is going to cause a large fraction of losses, ensuring a lower total number of trees for the butterflies to land in. There’s really no other way to view this. It is deliberate environmental destruction for no reasonable expectation of gain.

  9. These pathetic and dangerous climate obsessed fools are going to drive monarchs extinct with their “destroy the village to save the village” rationalization.

  10. Car and trucks on Interstate 10 from Arizona thru Texas in September and October do a pretty good number on the migrating population. Been there done that.

  11. And if the tree transplantation does not go well? The trees are dead and the monarchs have fewer trees to winter in. May I suggest they just plant some more at the higher altitude, water them, and give them fertilizer. The could always bag them and add CO2 so they grow faster.

    • Maybe the fir trees will move up (or down) in elevation when and if it becomes necessary; I hear it happens automatically (without human help).

    • They’re planting young seedlings not moving mature trees.
      “In fact, the researchers were able to shift more than 750 seedlings up a mountainside by up to 400 metres, as long as they planted the young trees under the shade of neighbouring bushes. This protected the seedlings from sunlight and extreme temperatures, says Arnulfo Blanco-García, a forest ecologist at UMSNH, and a study co-author.”

    • Maybe they could cross them with Ents, and then the trees can just walk to wherever they feel comfortable.

    • yeah from experience pine species dont transplant at all well if in the ground as natural seedlings
      potted ones from garden shops are ok
      id guess fir trees would be similarly inclined to die if uprooted and moved at anything over a few inches tall

  12. I do not have the patience and search skills to look for the ones back in the earlier decades, but believe me, it is a regular thing for them.
    And every time the reports are that it is unprecedented, they may all die, etc.




    • Oh, here, from April 2002 above:

      “January’s deadly freeze descended on two major winter resting grounds of the monarch in Mexico. The grounds are located on mountaintops mostly in Michoacan state, about a three-hour drive west of Mexico City.
      “It is, for sure, one of the largest die-offs ever,” says Seriff. “They had a die-off in the early 1980s of 2 to 3 million because of a severe winter storm, but this is far more catastrophic.”
      Naturalists who visited the grounds following the freeze reported enormous losses of as many as 250 million monarchs. They said about 74 percent died at one resting ground and 80 percent at another. Logging in the areas in recent years has thinned the fir forests that shelter the monarchs.”

  13. Notice that it was freezing that killed 31 to 38 % of the Monarchs. But we know that climate change is the cause of freakish weather…..rrrright….

    Another comment, milkweed is very succeptible to broadleaf weed spray so probably decline with efficient farming practices. If seeds were available somewhere, the same people that put out seeds for birds would probably grow more than enough of them. Or, some enterprising farmer would plant a pasture full of milkweed and charge people to see the Monarchs……or maybe mother nature is just having one of her normal population variations of one-tenth to ten times “normal”…..

  14. I live in eastern Colorado Springs. Usually the Monarch butterfly is a rare site in this area — we see more Painted-Lady butterflies during the fall migration. However, this year I don’t know what happened — Monarchs were very abundant.

    • Cheers!
      I live just south of Denver proper!
      Tell me, do you know anyone with private land that permits antelope hunting? There is barely any public land down that way.

    • In my part of central Maryland, the geese don’t migrate South any more, they stay here year-round. I guess they’ve found homes in the many golf course ponds and other bodies of water that stay mostly ice-free year round. Why couldn’t the Monarchs do something similar, and just not travel so far South to Mexico?

  15. What fuels butterflies ?, I mean they can’t make the 1000 mile flight to Mexico on one tank of fuel can they?
    Then once they arrive, and take their positions in the trees, what fuels them for the next month(s) ??

    • In the spring they leave their overwintering grounds and fly north a few hundred miles to find some milkweed where they breed and lay eggs. The larvae feed on the milkweed and a new generation hatches out and moves further north. By the fall about the fourth generation has reached the northern extent of their range, these are very long lived and migrate all the way south to the overwintering grounds where they rest up for the winter. In the spring they start all over again, the interesting thing is that these butterflies are about four generations removed from the last ones to have been there.

      • Watching a butterfly fly into a steady breeze, you wouldn’t think its wings had the right aerodynamics for it, then again the erratic flight avoids all but the youngest birds, which apparently learn quickly the horrible taste/burning of milkweed extract ?

        “Why do birds not eat monarch butterflies?
        Their caterpillars grow up eating milkweed, which contains some bitter chemicals. These are called cardiac glycosides because they cause vomiting and even heart failure in some animals. These chemicals protect milkweed because horses, cows, and deer won’t eat them. But the monarch caterpillar can.”

  16. I have been to see the Monarchs in Mexico twice. As in most poor countries the people are cutting trees for warmth and cooking fuel. It is actually quite cool there because you are at 12000ft. The basic problem is lack of access to affordable heating and cooking LG or Propane


    Menicholas’s comment. This freeze in Mexico occurs a couple of times a decade! And, according to subsequent reports the survivors multiply like crazy the following year. Maybe this freeze takes out the weaker butts, kills parasite infections and keeps the population sturdy and fertile. The physicians oath – First, do no harm- should be spread across the biological fields. These creatures have survived several glacial maximums.

    What happened to their milkweed from 100,000yrs ago to 10,000yrs ago. Well lets see if a mining engineer can help. The bleedin milkweed contracted out of Canada and the Northern States and the butts hung out for 100 millennia in the south, probably even farther south than now to escape more frequent freezes in Tampico.

    Shall I tell what they will do if the freezes in Mexico get more frequent? Well lets see. There probably is a southerly fringe to the wintering out area where they didnt freeze – yeah, they’ll fly another 100 mi further south. Let me check… can this be right ?

    “In Costa Rica it is common in open habitats, particularly pastures where its Asclepias host plant is abundant.

    This species can be found on both slopes of Costa Rica from sea level up to 2,500 m in elevation. It also lives on Cocos Island. Beyond the country’s borders, the monarch ranges and migrates throughout the world, including both of the Americas, the West Indies, the Philippines, Australia, and other regions.”

    • ah I was pretty sure the ones i have here this yr are monarchs too
      in aus
      everytime i water the yard i get 10 or more appearing
      theyve been very sparse but this year theres the most I have ever seen
      i now have to find what variant of milkweed we have here, from the description it looks like our “false caper” a lant with milky sap we use for small skin cancer removals may well be similar to usa version?

  18. Mods, no ad hominems, on topic, it shows the monarch is found in Costa Rica and a lot of places Gary

  19. This will assuredly harm the butterfly. That is the consequence of allowing our idiot universities to teach climate nonsense to the young. Given the shrieking alarmism, this only makes sense.

    The TRUTH is what has consequences in the real world.

    We have to WIN. We have to wake up the university life sciences departments.

  20. Do Monicul butterflies always nest on these t trees What happens if they cannot find a milkweed tree.

    Also my understanding is that its not the original butterfly which completes the long journey, but its offspring.
    So if no milkweed trees will any other tree do ?. True no poison in the system to protect them.


    • Milkweed is for the larvae to feed on, about four generations journey north during the summer but the last generation makes it all the way back to Mexico.

  21. Here in the sub-tropical areas of the North Island f New Zealand, the Monarch Butterfly population seems to be doing just fine. When we lived in the UK (outer London) we noted a thriving Monarch population there, too. So much so that Monarch caterpillars and butterfly habitats are often sold by education supply businesses to junior-class teachers to provide the children the brilliant experience of observing the caterpillars created their cacoons then hatch.

  22. looked up your american milkweeds
    nothing like that here
    wondering what the hell they are using for food downunder?
    I have honeysuckle flowering but not much else
    the staggering heat the last few days has burnt most plants inc corn n beans to a crisp
    really really crisp and dry
    in 8hrs after being saturated this morning;-(

  23. All seems pretty weird to me. Two things to bear in mind whenever you see stories like this about insects.

    First thing, they produce a lot of eggs. A heck of a lot. Hundreds, and sometimes thousands. That means that, over time, more than 98-99 percent of the offspring don’t make it to breed themselves. So counting monarchs, or any insect, to get an idea of how well the insect is doing, can be very misleading. The number of insects one year is a very poor indicator for the number you will see next year. It might be twenty times, or a twentieth, and means zilch. It’s not like monitoring the population of Eagles or Tigers. Huge fluctuations in numbers are absolutely normal, and rushing to any conclusion, let alone indulging in the nonsense represented by this story, is just crazy.

    The second thing (and as a Brit I know very little about Monarchs or Milkweeds, so I’m open to correction) is that here we are looking at a rapidly dispersing species, quite likely with a diverse gene pool. They get all over the place (even occasionally seen in UK), and fly great distances. They are constantly turning up in new places, colonise (sometimes just temporarily) widely, and I think it safe to say that they could not in any reasonable judgement be described as endangered. Looks to me like their distribution is really limited solely by their close association with milkweeds. I would guess that Milkweeds are reasonably classed as weeds, that is, colonists of disturbed and marginal ground, and, just like many butterflies that are associated with weeds (for instance, the several white Pierids that eat cruciferous plants like cabbage) they are always dispersing, finding the temporary locations where their foodplants are. So, if you want Monarchs, plant Milkweeds. It is hard to imagine the stupendous climate changes that would be needed to exterminate Monarchs. They may be eliminated locally, and then appear again after a few years. Nothing at all to worry about.

    • It’s somewhat more complicated than that, milkweed abundance has an effect on breeding but is widely distributed. However the fir trees where they overwinter are much more narrowly distributed and loss of them could have a much bigger effect on the population as a whole.

  24. I’m an arborist and agronomist and have been on hand to witness the transplantation of trees from one site to another. The risk involved in transplanting trees at all is considerable – unless the trees are no more than an inch in diameter because then their roots can easily be dug up with 90% of the roots going with the trees. But if they’re thinking of digging up young trees at about 4 or 5 years of age then even with a giant earth moving machine that is designed to pick up the tree with a major portion of it’s roots there’s still a 50-50 chance of the trees surviving the transplant. And even if they survive that it’ll still take them another few years to regain their vitality and be a benefit to the butterflies. If they’re thinking of transplanting mature trees then the probability of success drops precipitously. A 10 year old tree, on the average, has a 5% chance of surviving the transplant. And assuming it will return to it’s previous level of vitality that should take another 10 years or so to accomplish. Somehow I don’t think they understand that transplantation of trees is fraught with all kinds of risks and its not like one has a flower in a flower pot and pops it out of the pot and drops it into an accommodating hole in one’s garden. It doesn’t work that way.

    • According to the paper they were actually planting seedlings.
      “In fact, the researchers were able to shift more than 750 seedlings up a mountainside by up to 400 metres, as long as they planted the young trees under the shade of neighbouring bushes. This protected the seedlings from sunlight and extreme temperatures, says Arnulfo Blanco-García, a forest ecologist at UMSNH, and a study co-author.”

      Those have been planted over the last three years and I would think that forest ecologists do know something about the process. It typically reaches about 12′ in 10 years.

  25. Some people are actually doing something about the decline of Monarch butterflies by planting milkweed. No models, sketchy papers, or grants needed.

    No no no, we must overturn capitalism and democracy, live on intermittent power and ask permission for a procreation license in order to save the Monarchs. A shallow sad and bleak existence for all remaining humans (except the high priest hypocrites) will make everything better.

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