Recent Boston Globe "monarchs are threatened" article

[Patrick Foley]

Paul,

No scientist considers the species Danaus plexippus threatened with 
extinction. It is widespread over several continents, and its host 
plants are abundant in many places.

But as we have cleared up several times on this list, the Monarch's 
Eastern NA migration behavior is a much more fragile thing. Why?
1) This kind of migration is not common in butterflies. It apparently 
requires just the right conditions.
2) These conditions include the availability of a wintering site with 
special features. This wintering site in the Oyamel fir forests of 
Mexico is now somewhat legally protected, but as any one who has worked 
in Mexico knows, conservation in Mexico is not a sure thing. Are you 
against protecting the site?
3) The conditions for migration also include the presence of abundant 
milkweed host plants all along the flight path of the Monarch. How much 
hostplant density heterogeneity is acceptable? We don't know. Chip 
Taylor is certainly correct that the elimination of the host plant will 
end the migration. Surely you are not arguing with that statement. 
Presumably you are claiming that milkweed populations will remain 
sufficient in the future even with increased intensity of "weed" 
control. How do you know this? What do you know about the future density 
and distribution of milkweeds that everybody else doesn't? Are you not 
troubled by the loss of natural habitat and even roadside weeds in the 
American Midwest?

Let me make the usual protective statements. I have no financial 
interest or grant money involved in Monarch research. I do want US and 
Mexican farmers to be able to grow crops. I have a PhD in genetics so I 
am not dumbly reactive about genetically engineered crops. I eat food. I 
do not want Big Brother controlling every aspect of our lives.

But I think it is worth protecting the overwintering site, and I think 
that the eradication of milkweeds in large tracts of land will end the 
migration as we know it.

I think your scepticism of scientists and conservationists is a good 
thing. Science proceeds through scepticism. But this scepticism 
contrasts strangely with your willingness to embrace weak arguments 
(such as the claim that Monarch populations are stable (which they are 
not -- they show lots of environmental stochasticity which does affect 
population viability, and trait viability) or that past population 
trends are a secure guide to the future (even though that future will 
involve fewer milkweeds we strongly suspect)). The data you present are 
interesting, and worth considering. But I find it hard to believe that 
you really think they tell the whole story. So tell your part of the 
story. Critique your data as strongly as you critique the "scientists", 
and soon you will be doing science. And maybe we will figure out what 
conditions are needed for the persistence of the Monarch's Easstern 
North American migration.

Or maybe the scientists are just out to destroy the American way of life?

Patrick
patfoley at csus.edu

Paul Cherubini wrote:

>As you read though the recent July 6 Boston Globe article below, consider 
>the following important facts the scientists & conservationists have
>left out with the predictable result that the public gets subliminally 
>dumbed down into thinking the monarch migration is seriously
>threatened by human activity: 
>
>1. Illegal logging has not been occurring in the monarch cluster
>areas and therefore has not "opened the forest canopy to winter 
>storms" as implied by the article.
>
>2. While it's true the new herbicide resistant crops like corn and 
>soybeans, first introduced in 1996, have helped farmers improve 
>weed control, it's also true the size of the monarch migratory /
>overwintering population has continued to be high and stable overall:
>http://www.saber.net/~monarch/mexicopopsize.jpg.  Indeed, for 
>many decades farmers have been continually improving weed 
>control in their crops using various technologies yet as the graph 
>shows, monarchs are as abundant as ever. So how can any monarch 
>scientist reasonably consider herbicide resistant crops a "threat" to 
>the continued existence of the monarch migration?  
>
>In 1999 Dr. Chip Taylor speculated even more profoundly 
>about the threat posed by herbicide resistant crops:
>http://www.findarticles.com/p/articles/mi_m1200/is_1_155/ai_57770149
>"Open fields of corn and soybeans are popular spots for milkweed, 
>but the plant may soon be wiped out as crops are bio-engineered to
>survive pesticides designed to kill all weeds, says Taylor. Loss 
>of the milkweed would threaten the monarch's survival."
>
>3. Heavy storm kills at the monarch overwintering sites
>are nothing new.   They have been happening two or three times every 
>decade, on average, at the overwintering sites in both California 
>and Mexico for as long as anyone can remember.  And each time 
>the monarch population has ALWAYS recovered within 8 months. 
>So how can any monarch scientist reasonably consider these 
>periodic heavy storm related winter kills a "threat" to the  continued
>existence of the monarch migration?  
>
>Paul Cherubini, El Dorado, Calif.
>=============================================
>Butterfly Migration Route Threatened by Weather, Industry
>
>By Carolyn Johnson, Boston Globe Correspondent July 6, 2004
>
>Soaring and gliding on delicate orange-and-black wings, three monarch
>butterflies flew all the way from Vermont to central Mexico last fall.
>
>Researchers recently confirmed that the insects they had
>tagged in Vermont in September were the same ones
>they found in El Rosario, Mexico, -- roughly 2,400 miles away -- in
>December. The discovery marked the first confirmed arrivals of Vermont
>butterflies since a lone tagged specimen was found in 1999.
>
>A monarch ''weighs half a gram. It has a really tiny brain," said Chip 
>Taylor, director of Kansas University's Monarch Watch, which tries 
>to build interest in the butterfly through efforts like the Vermont 
>tagging. ''It's sort of a magical feat that these butterflies perform, in a 
>way."
>
>In recent years, naturalists and biologists have expressed concern about 
>the future of this unique migratory phenomenon, now threatened by a 
>variety of global environmental changes.
>
>During the last several years, demand has climbed for softwood trees 
>like the Oyamel fir, which serve as winter bungalows for an estimated 
>half-billion butterflies in the mountains of central Mexico. Illegal 
>logging within the butterfly reserves has opened the forest canopy
>to winter storms.
>
>''It's like poking big holes in your winter coat," said Bryan Pfeiffer, a
>consulting biologist for the Vermont Institute of Natural Science, 
>who tags every butterfly he can find.
>
>Within the United States, habitat may also be threatened as farmers 
>plant new herbicide-resistant crops and liberally spray chemicals, 
>threatening the milkweed that provides an essential food source for 
>monarch caterpillars.
>
>A year-old study published in the Proceedings of the National 
>Academy of Sciences forecast the type of wet and cold weather 
>for monarch territory that could kill huge numbers of butterflies.
> ''Right now we may be looking at the very beginning of this 
>impact," Taylor said.
>
>This past winter, 70 percent of the population died, he said, as
>moisture from the Pacific Ocean was drawn into central Mexico, 
>soaking, and then freezing the insects.
>
> 
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