quinta-feira, 14 de março de 2013

Monarch Butterflies Numbers Down Again

Monarch butterfly on Swamp milkweed wildflower. (Credit: © Mark Herreid / Fotolia)

Mar. 13, 2013 — Bad news again for the Monarch butterfly: Drought conditions and historic wildfires the past few years continue to decrease their numbers as they wing across Texas this spring. Worse news: milkweed plants -- the only kind they need to survive -- are also not in plentiful supply, says a Texas A&M University Monarch watcher.

Craig Wilson, a senior research associate in the Center for Mathematics and Science Education and a longtime butterfly enthusiast, says reports coming from Mexico where the Monarchs have their breeding grounds show their numbers are significantly down, a disturbing trend during much of the past decade.

"The severe drought in Texas and much of the Southwest continues to wreak havoc with the number of Monarchs," Wilson explains.

"The conditions have been dry both here and in Mexico in recent years. It takes four generations of the insects to make it all of the way up to Canada, and because of lack of milkweed along the way, a lot of them just don't make it."

The dry conditions and changing farming practices are hampering the growth of milkweed, the only type of plant the Monarch will digest as it makes its trip north. Texas has had dozens of wildfires in the past few years that have hampered milkweed growth, and even though there are more than 30 types of milkweed (Asclepiadaceae) in the state, the numbers are not there to sustain the Monarchs as they start their 2,000-mile migration trip to Canada. Increased use of pesticides is also adversely affecting milkweed production, he notes.

"But if people want to help, they can pick up some milkweed plants right now at local farmer's cooperative stores," he says, "and this would no doubt be a big boost to help in their migration journey."

The Monarch reserves are in the Mexican state of Michoacan. It's an area where tens of millions of Monarchs spend the winter and mate before heading north, Wilson points out.

"On a recent visit to the Monarch overwintering sites in Michoacan, former President Jimmy Carter said: 'The Monarch butterfly unites the three countries of North America in peace.

It is an ambassador of peace which requires protected areas and ecosystems that are preserved through sustainable agricultural and forestry practices. We need to work together to maintain a healthy and balanced ecosystem for all North America," Wilson adds.

"It is important to have a national priority of planting milkweed to assure there will be Monarchs in the future," Wilson believes. "If we could get several states to collaborate, we might be able to provide a 'feeding' corridor right up to Canada for the Monarchs."

Wilson is currently adding a variety of milkweed plants to the existing Cynthia Woods Mitchell Garden on the Texas A&M campus. He recommends the following sites for Monarch followers: Journey North, Texas Monarch Watch and Monarch Watch.

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