REPOST- broken link on my last one Re: [leps-talk] Why aren't Mexico's overwintering monarchs in the news yet this winter?

Thu Feb 14 00:04:27 EST 2002

Kurt wrote:

> I certainly welcome new data; It would be happy news indeed
> if there as no threat, actually, to the Monarchs in Mexico etc.

Kurt, these pictures http://www.saber.net/~monarch/changes1.JPG
are not new data.  They were published on a USGS
website http://edcwww.cr.usgs.gov/earthshots/slow/Angangueo/Angangueo
over a year ago.

Now let me explain how you may have been led to
the conclusion that there has been "a circa 50% loss
of available forest land for monarch overwintering in Mexico"

On Sept. 12, 2000 a New York Times article reported the following alarming
and depressing information:
-------------------------------------------------------------------------------------------
Monarch Butterflies Lose Much of Their Wintering Grounds 
New York Times,  Sep 12, 2000
Authors: Carol Kaesuk Yoon

excerpts: (capitals my emphasis)

"Now an international team of researchers has reported that what was a
broad swath of thousands of acres of intact forest just 30 years ago has
since been reduced to peppered remnants in a sea of farms, homes,
cattle-grazing areas and logged and degraded woods."

"The survey, the first scientific study of the monarchs' habitat in the mountains
of central Mexico, mapped forest changes using aerial photographs taken over
three decades. The findings, which were made available to The New York
Times, showed that ONLY A LITTLE MORE THAN HALF OF WHAT
WAS INTACT FOREST REMAINED. The rest has suffered some degree
of degradation, from minor logging to having had the forest entirely removed."

 ''From what I've seen there year after year, I predicted it would be bad
and getting worse,'' said Dr. Lincoln P. Brower ''But I didn't predict it would
be this bad. The maps just floored me.''

"Dr. Karen Oberhauser, praised the quality of the work, saying:
''It's the first study and a really important study. We didn't expect the
change to be this great.''
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Now how could have 50% of a forest disappeared without anyone
noticing it over a 30 year period? Well it didn't disappear and these photos
prove:it http://www.saber.net/~monarch/changes1.JPG

What Dr. Brower did was develop COMPUTER ANIMATED maps of
deforestation. To quote Dr. Brower: "basically aerial photographs are
stereographically analyzed and categories of deforestation are defined
objectively, digitized, and then mapped and analyzed mathematically"

Here are 1973 vs 2000 satellite photos and Dr. Brower's corresponding
computer animations:http://www.saber.net/~monarch/1973vs2000.jpg
You will note the satellite photos show virtually zero change in the forest
cover whereas the Brower's animation shows horrific changes. What's the
catch here?

Indeed, anyone viewing Brower's animation would quickly gain the
mistaken impression that around 44% of the native forests within and near
the monarch sanctuaries have been destroyed since 1971.

But are Brower's animations accurately depicting a loss of 44% of the native
forests since 1971?  No I don't think so. Here's why:

If you take this the top pair of these close up satellite photos
http://www.saber.net/~monarch/changes1.JPG and match them against
Brower's animation you get this comparison: