Dr. Sears, Monarchs, Bt corn

Paul Cherubini cherubini at mindspring.com
Tue Oct 10 13:08:20 EDT 2000

Dr. Chip Taylor wrote:
> Paul Cherubini has provided us with another misrepresentation. 

I submit that Dr. Chip Taylor has provided us with many
subtle overstatements and exaggerations. For example, 
consider his talk a few weeks ago in Central Park,
New York:


Dr. Taylor said:

"The monarch migration is truly one of the world¹s
wonders, yet the continuation of this phenomenon is

1.deforestation in Mexico

2.habitat loss in the summer breeding range in the United 
   States and Canada

3.changes in agrigultural practices, including the
   use of genetically modified crops

4. global warming

My take on Dr. Taylor's comments:

Item #1: Dr. Taylor fails to disclose that there are approx.
33,000 acres of oyamel fir forest in the monarch overwintering
area in Mexico and the monarchs' occupy a miniscule 20 acres of this 
acreage. Even if we assume the butterflies really need
something like 500 acres to comfortably
thrive,  it could be centuries before the butterflies
are THREATENED due to deforestation (because of the huge
amount of forested area available to them).  Moreover, it is 
downright silly to think that maintaining 500 hundred acres of
forest cover (roughly 1 square mile) for the butterflies 
represents a major technological hurdle. 

Item #2:  There are around 7,000,000 square miles of land in
the USA. Somewhere between 600-900 square miles of this land 
each year is replaced with concrete and asphalt due to urban sprawl. 
At this rate we would be looking at 400+ years before even 5%  
of the current open land area is lost to urban sprawl.To claim the
monarch migration phenomenon is "threatened" by
"habitat loss in the summer breeding range" is a serious

Item#3: Over $100,000 of studies to date indicates Bt corn
poses no THREAT to the monarch. Dr. Sears pointed 
out that even the most toxic form of Bt corn, that represents just
1% of the Bt corn crop acreage may not be lethal to monarch
larvae in real world field situations. Last year Dr. Taylor 
told reporters Bt corn "could raise hell with monarchs". 

Item #4: Global warming a threat to the monarch migration?
How? If anything, global warming means milkweed plants
can thrive further north into Canada, hence expanding the
monarchs' summer breeding habitat. In my opinion, it is
unprofessional behaviour for a university professor to cavalierly
(without data or a model) tell a public crowd in New York 
that the  continuation of the monarch migration phenomenon is
THREATENED by global warming. 

Dr. Taylor's may try to say what I just wrote above is itself 
somehow a misrepresentation or an example of "Cherubini's 
conspiracy theories"  In order to present Dr. Taylor's views 
as accurately as possible, below I have copied and pasted 
statements he currently has posted on his own website:

Dr. Taylor wrote: (capitols my emphasis)

"Given the great numbers of Monarchs (up to 100 million)
that gather to migrate each fall, it is hard to imagine them 
facing any threat of EXTINCTION. In reality, however, 
Monarchs and their amazing annual migration are 
SERIOUSLY THREATENED by human activities, in both
their summer and overwintering sites. Many of
these threatening activities hinge on the destruction of 
good Monarch habitats. 

In the north (the United States and Canada), Monarchs face
direct habitat destruction caused by humans. New roads, housing
developments, and agricultural expansion - all transform a natural
landscape in ways that make it impossible for Monarchs to live
there. Monarchs in the north also face more subtle habitat 
destruction in the loss of their host plants. Milkweed, the plant
larvae feed on exclusively, is considered a noxious weed by 
some people, which means it is often destroyed. In some areas
across North America, milkweed plants are also being severely 
damaged by ozone. Both milkweed and adult nectaring plants 
are also vulnerable to the herbicides used by many landscapers,
farmers, gardeners, and others. And Monarchs themselves can 
be killed outright by many pesticides.

Eastern Monarchs migrate only to the Transvolcanic Mountains 
in Mexico where there are only eleven to fourteen known sites 
each year. Each site is a few hectares in size and contains 
millions of Monarch butterflies. This combination -a high 
concentration of individuals in a only few small sites - makes the
possibility of habitat destruction in Mexico VERY SERIOUS."

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