Decline of monarch butterflies overwintering in Mexico

[Mona Miller]

http://www.saynotogmos.org/ud2011/fp-co ... r_2011.pdf
The PDF has the complete article.
Decline of monarch butterflies overwintering in Mexico: is the migratory phenomenon at risk?
Abstract.
1. During the 2009–2010 overwintering season and following a 15-year downward trend, the total area in Mexico occupied by the eastern North American population of overwintering monarch butterflies reached an all-time low. Despite an increase, it remained low in 2010–2011.
2. Although the data set is small, the decline in abundance is statistically signifi-
cant using both linear and exponential regression models.
3. Three factors appear to have contributed to reduce monarch abundance: degradation of the forest in the overwintering areas; the loss of breeding habitat in the United States due to the expansion of GM herbicide-resistant crops, with consequent loss of milkweed host plants, as well as continued land development; and severe weather.
4. This decline calls into question the long-term survival of the monarchs’ migratory phenomenon.

[Paul Cherubini]

Midwestern farmers have been improving weed control WITHIN the crops for decades, not just since the adoption of GM crops in the 2000's. But farmers don't spray the crop MARGINS so milkweed is still abundant on GM crop margins and monarchs are more abundant on these crop margins than anywhere else in the USA. No where else in the USA besides the GMO farmlands of the upper Midwest are their 1000's of overnight roosts spread out over 10,000's of square miles each containing 100's or 1000's of butterflies.

In Spain, Australia and New Zealand the monarch migrations persist even though the overwintering sites contain only mere 10's or 100's of butterflies. And in California the sites contain only 1000's or 10,000's of butterflies. So it is not necessary to maintain a population of 100,000,000's of butterflies in order for the migration phenomenon to survive.

[blazing star]

You've never posted any evidence that monarchs only use GM Croplands. I have, however, seen your video and pics contrary to this that monarchs are relegated to small island of habitat not destroyed by GM Croplands.