Mexican deforestation - Monarch butterfy

Paul Cherubini cherubini at mindspring.com
Wed Sep 13 22:46:04 EDT 2000


Jeffrey A. Caldwell wrote:
> 
> Test: Ottawa Citizen online article:-
> 
> http://www.southam.com/ottawacitizen/newsnow/cpfs/world/000912/w091278.html

> some tourists wore paper masks against dust rising from deforested land.

Since winter is the dry season in the highlands of southern Mexico, foot 
traffic on trails does kick up a little dust. Also, because of dryer than normal
weather, more dust has been blown off dormant cornfields in late winter than
would normally be the case. A temporary cosmetic issue.

>A new study of aerial photographs taken over the last 29 years shows damage or
>destruction of 44 per cent of the fir forest that serves as wintering grounds for the
>Monarch butterfly.

"Damage" is not defined nor is "intact forest" defined. These forests have been 
selectively logged for centuries."Destruction" is largely limited to areas below 
the altitude where the butterflies cluster.  "Destruction" = agricultural clearings. 
What isn't mentioned is that these clearings provide nearby water and nectar
sources which are exploited by thousands of the butterflies. If the forests were
actually being cleared at the altitude where the butterflies overwinter there would 
be a need for reforestation projects. To date there have been no such projects 
within the butterfly sanctuaries because there has been no deforestation. 

> He [Brower] also reports when dusty, dry winds blow through thinning forests,
> the  butterflies are more likely to fly down to nearby lowlands streams to drink 
> thus wasting precious energy needed for the trip back. 

Forest density at the altitude where the butterflies overwinter has not been changing.
And the butterflies cluster within a very wide range of densities.
The alledged "thinning" occurs at lower altitudes which is not butterfly habitat.
Dr. Chip Taylor of the Monarch Watch has reported good numbers of monarchs 
reaching the northern latitudes of the USA in spring for the last two years in a row.
In other words, there is no hint the butterflies are suffering from any kind of
physiological stress, dying prematurely, etc.

> Brower said in 50 years there could be "basically nothing left." 

Again the crucial piece of information that is not being disclosed is that the forest
is not dissappearing at the altitude and SW facing slope exposure where the butterfles
overwinter. Crops cannot grow well at that altitude, hence there is little 
pressure to clear the forest.  Another piece of crucial information not being disclosed
is that the butterfly clusters require only 20 acres of forest space - mere pinpoints
within the thousands of acres of available forest. Not exactly a dire habitat
encroachment situation. 

Paul Cherubini


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