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Bug Earth Science

Monarch Butterfly Populations In the West Are Down an Order of Magnitude (qz.com) 100

An anonymous reader quotes a report from Quartz: Far fewer [monarch butterflies] were heading south this year, and those that have arrived did so a month late, according to Xeres, a non-profit conservation group for invertebrates. One researcher said it was the fewest monarch butterflies in central California in 46 years. Surveyors at 97 sites found only 20,456 monarchs compared to 148,000 at the same sites last year, an 86% decline. It's possible more insects will make the journey late this year, says Xeres, but that now seems unlikely. The minimum population size before the species experiences "migration collapse" is unknown, but a 2017 modeling paper in Biological Conservation (pdf) found that 30,000 butterflies adult butterflies are probably the smallest viable population. Without this critical mass, there aren't enough insects in the western monarch population to continue one of the world's most remarkable lifecycles.
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Monarch Butterfly Populations In the West Are Down an Order of Magnitude

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  • by Anonymous Coward on Sunday December 02, 2018 @10:27AM (#57736290)

    Why not set aside a small percentage for wild grasses, wild flowers and specifically for the Monarchs: milkweed

    • by ShanghaiBill ( 739463 ) on Sunday December 02, 2018 @10:51AM (#57736386)

      Why not set aside a small percentage for wild grasses, wild flowers

      I did this and got a citation from the city requiring me to cut down the weeds.

      • Yep, Milkweed is considered a noxious weed.

        • by ffkom ( 3519199 )
          Are there really regions in the world where the presence of milkweed is considered a significant risk? Sounds weird...
          • If you plant things too close to buildings (or in certain places that sometimes only the fire department can explain), the fire department can tell order to cut it out to prevent the spread of fire.
          • by dryeo ( 100693 )

            According to http://www.omafra.gov.on.ca/en... [gov.on.ca] Manitoba, Ontario, Quebec and Minnesota. Seems that it is toxic to livestock.
            Does Milkweed even grow in the west? I don't think I've seen it here in BC.
            Strangely, there seemed to be an unusual number of monarchs here in SW BC. Usually just see the odd one, this year they seemed to be everywhere in late spring, never saw so many. I don't know if ours migrate or not.

            • Re: (Score:3, Funny)

              Strangely, there seemed to be an unusual number of monarchs here in SW BC. Usually just see the odd one, this year they seemed to be everywhere in late spring, never saw so many. I don't know if ours migrate or not.

              Those are the ones that usually summer in Pismo Beach. This year, they have gone to Canada in protest of Trump's policy on refugees.

  • affects lots of species

    Fortunately monarch butterflies live in many parts of the world , even NZ

    • The insect population is declining worldwide. I am talking about 70 to 80 percent.

      https://www.independent.co.uk/... [independent.co.uk]

      I donâ(TM)t think that draught is the reason for a worldwide problem.

  • by Anonymous Coward

    That's the nicest explanation for why "only 1.5 degrees" matter so much, that I've seen:

    In nature, everything is in a stable balance of many dependent cycles, where everything is juuust right. Even for life itself to even exist.
    Nudge one of those balances off only a bit too much, and the entire thing goes over the edge and spirals out of control. Taking things with it, that you never thought of.

    To me, this is also the best approach, to make sense of "chaotic" behavior. (As in: chaos theory)

    Only lossless cyc

    • Re: (Score:2, Informative)

      by Anonymous Coward
      Yes, if only we all paid carbon tax, the poor butterflies would... still be dead.
    • by arth1 ( 260657 ) on Sunday December 02, 2018 @02:03PM (#57737136) Homepage Journal

      To me, this is also the best approach, to make sense of "chaotic" behavior. (As in: chaos theory)

      Killing off the butterflies might reduce the number of hurricanes!

    • You forget momentum.

  • Monarch apocalypse (Score:5, Interesting)

    by ElitistWhiner ( 79961 ) on Sunday December 02, 2018 @10:45AM (#57736358) Journal

    30 yrs. living in SoCal, the wildfires in San Diego County began in the 80's where it was first noticed effect on Monarch migration. Each February Point Loma which stuck out into the sea would afford the Monarch a nutritious waypoint on their migration northward. The surrounding canyon's wild milkweed air would flow for days in a stream of butterflies. With successive wildfires the drop in Monarch sightings transitioned official narrative from migration change to population tragedy to loss of food source.

    Today the coastal flyway is host to few Monarchs and the loss for those hoping for a return defies the Monarch apocalypse. Now, living NoCal, the Monarchs flew through the Bay Area's Marin wetlands on their way south this October. It was a happy reminder however brief, one afternoon, that they aren't dead - yet.

    • by Anonymous Coward

      Amazing how humans are so self-preoccupied. Even your post goes on how it would be a loss for fans.

      We as a species should go extinct instead.

  • Urban Sprawl (Score:5, Insightful)

    by Marxist Hacker 42 ( 638312 ) * <seebert42@gmail.com> on Sunday December 02, 2018 @10:58AM (#57736416) Homepage Journal

    The reason the butterfly population is down is because of urban sprawl in Washington and Oregon destroying their habitat. This is a direct case of cities causing extinction of other species.

    Farms, by their very nature, cannot eliminate all weeds, and the milkweed these butterflies need to feed on is plentiful in the countryside, but is considered a noxious weed by urban rules.

  • Soon we will have the migration of the monarch butterfly (singular).
  • Probably this reason (Score:5, Interesting)

    by Ol Olsoc ( 1175323 ) on Sunday December 02, 2018 @11:20AM (#57736502)
    Monarchs take some years to complete their migration cycle. A few years back, we noticed a drop in population. There was an extensive program for people to plant milkweed, one of the Monarch's main food sources. Here in the east, the population has rebounded.

    Some folks have planted milkweed beside the roads near natgas corridors - a lot. The number of Monarchs flitting around last year and this has been impressive. So that bubble of butterflies should be reaching the west in a few years, assuming food sources in the midwest can accomodate them.

    Side note: I often take the Cape May - Lewes Ferry, which crosses the Chesapeake bay between New Jersey and Delaware. Monarch butterflies often ride the slipstream behind the ship with us during the late summer and fall.

  • Maybe they were tired of all the riff raff and went somewhere else?
  • by v1 ( 525388 ) on Sunday December 02, 2018 @01:55PM (#57737112) Homepage Journal

    I live in central Iowa, in a city that has lots of trees and (in the 1980's anyway) had large areas of the city that were not heavily developed and basically had little islands of forrest in the middle of the city. Around 1985, I got to see an incredible sight. The monarch migration passed right through town, specifically stopping to rest at a wooded area not 300 feet from my apartment.

    There were lots of older trees there, mainly maples, that stood 70-100ft tall, and they were dripping with butterflies. Every leaf had several butterflies on it, all of them slowly flexing their wings, making the entire tree look like it was breathing, in a shimmering silver-brown color. There was no green to be seen anywhere in the canopy, everything was covered with monarchs. The branches were even getting visibly weighed down from weight of butterflies, some branches that normally were ten feet off the ground were within hand's reach. You could reach up and slowly brush your hand through a living curtain of butterflies. It was amazing!

    This went on for about three days. There were monarchs flying lazily around all over the place, and if you walked slowly though the area, you'd have several of them landing on you as you walked or stopped to stare at them. Monarchs are very large butterflies too. I wouldn't even want to attempt to count how many there were. I did't own a camera back then, but I wish I did. I would have taken so many pictures. But back then I was pretty young, and didn't recognize that this was a sight I would probably never get to see again, so all I have of it are the memories of the trees filled with butterflies.

    We had a fair amount of "ditch weed" (milkweek) in the area, especially in the ditches along the gravel roads outside town. I used to go to the empty lots where there was still a lot of "prairie" type land between the neighborhoods, where milkweed could be plentiful, and see if I could find the vibrantly colored monarch caterpillars. They're striped yellow, white, and black. Sometimes if I found one I'd take it home along with some milkweed, and raise it. I'd have to go back and pick more milkweed from time to time. Then it would stop eating and climb to a stick in the jar and make a chrysalis and I'd have to wait a month or so for it to hatch and fly away. it started out a very interesting shape, colored green to match the milkweed, but with a ring of gold (like jewelwry gold) spots around the top crown area, like someone had painted drops of gold paint in a halo around the top of it (like https://naturetime.files.wordp... [wordpress.com]) A week or so before it hatched, the chrysalis would become transparent, and you could see the gold wings folded up inside, sometimes moving a little.

    Nowadays, there are still quite a few trees in town, most yards have a tree, but there are very few vacant grass lots or clumps of trees inside town. Outside town, it's all farmland now, so again not much in the way of woods. But still lots of milkweed in the ditches around town, and I do see a monarch from time to time, but they're pretty rare. I've been considering planting some milkweed in my front yard now, to see if I can attract some monarchs. We don't really consider it a problem weed here in town. The plants are pretty solitary and don't spread fast like some other "weed" do. They have a somewhat attractive large flower also. Not something you want to eat though, they produce a large volume of a very thick white milky sap if you break off a leaf. Monarch caterpillars are one of the few insects that can eat them, and they retain the toxin as butterflies also, which is why the caterpillars and adults are so brightly colored - they're a toxic meal for most birds.

    I miss those days!

    • I wonder if you have native milkweed there. In SoCal I probably have tropical. I just pulled up a few yesterday, having independently decided not to let them grow during winter. Karma, man, thx for the post.

    • by Shaiku ( 1045292 )

      I had a similar experience growing up next to a eucalyptus grove right in the middle of the migration path. In the morning the trees would come alive as tens of thousands of butterflies began beating their wing to wake up, then as the sun's rays hit they would disperse into the air and fill the grove with twirling, beating butterflies. The weaker ones would be dead and dying on the ground and others would float all around from the canopy to the floor--it's impossible to convey the experience in words but

  • Comment removed based on user account deletion
  • We planted our Milkweed garden a number of years ago. It look a few years but now we get Monarch's each year. In fact this year we had the most Caterpillars in all the time we had the garden. We see our Caterpillars in Late August and September, this year they wiped every Milkweed leaf in the garden.
  • I've seen 2-3 monarchs most years- mostly a curiosity. This year there were a few dozen around - order of magnitude checks out. Northern New England.

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