Monarch butterflies numbers down again this year

Reports suggest that Monarch butterfly numbers will be down almost 30 percent in 2012 as they make their annual trek from their breeding grounds in Mexico.

Monarch butterflies numbers are expected to be down again in 2012, say reports.

Reports by the World Wildlife Fund, private donors and Mexico’s Michoacan state all show that Monarch numbers will be down almost 30 percent in 2012 as the butterflies make their annual trek from their breeding grounds in Mexico and move across Texas, said Craig Wilson, a Texas A&M University researcher.

Photo credit: dave and rose

The figures show an alarming decades-long decline in their numbers, Wilson says. He added:

The latest information shows that Monarchs will be down from 25 to 30 percent this year, and that has been part of a disturbing trend the last few years.

Last year’s severe drought and fires in the region no doubt played a part, resulting in less nectar for the Monarchs as they migrated south. But estimates show that each year, millions of acres of land are being lost that would support Monarchs, either by farmers converting dormant land for crop use – mainly to herbicide tolerant corn and soybeans – or the overuse of herbicides and mowing. Milkweed is the key plant because it’s the only plant where the female will lay her eggs.

The loss of such lands is a critical factor in the Monarchs’ survival, Wilson explained. Recent estimates suggest that 100 million acres of land have already been lost that previously supported Monarchs,” Wilson notes.

Most of the Monarch reserves are in the Mexican state of Michoacan. It’s an area where Monarchs spend the winter and mate before heading north.

This year, according to the Texas Monarch Watch, Monarchs covered about 7.14 acres of forest in their Mexican breeding grounds compared to 9.9 acres last year, and it shows a continued long-term downward trend in Monarch population since official surveys began in 1994.

Bottom line: Reports suggest that Monarch butterfly numbers will be down almost 30 percent in 2012 as the butterflies make their annual trek from their breeding grounds in Mexico and move across Texas.

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