Drought conditions contribute to decline in monarch populations

In this photo taken Feb. 15, 2013, Monarch butterflies are collected in a net to be tested for the ophroyocystis elektroscirrha parasite that inhibits their flight, at El Capulin reserve, near Zitacuaro, Mexico. Every year, millions of monarchs migrate from the eastern United States and Canada to central Mexico, a journey of over 2,000 miles. The tiger-striped butterflies arrive in late October and early November to hibernate in fir trees until February. The scientist is part of a research project conducted by the World Wildlife Fund of Mexico and the University of Georgia and University of Minnesota. (AP Photo/Marjorie Miller) less In this photo taken Feb. 15, 2013, Monarch butterflies are collected in a net to be tested for the ophroyocystis elektroscirrha parasite that inhibits their flight, at El Capulin reserve, near Zitacuaro, ... more Photo: Marjorie Miller, STF Photo: Marjorie Miller, STF Image 1 of / 5 Caption Close Drought conditions contribute to decline in monarch populations 1 / 5 Back to Gallery

Monarch butterfly populations have been fluttering away in the last decade, and a local expert points to Texas' drought conditions and recent wildfires as key factors in the decline.

The number of monarchs as well as milkweed plants, which are key to the insects' survival, are in low supply, said Craig Wilson, a Texas A&M university researcher with the Center for Mathematics and Science Education.

Wilson said reports from Mexico, where the monarchs have a breeding ground, show that in the last decade their numbers have been dropping significantly.

The area of forest occupied by the butterflies in their winter refuge in Mexico dropped 59 percent this year, the lowest level since comparable record-keeping began 20 years ago, according to a survey by Mexico's National Commission of Natural Protected Areas that was disclosed this week. It is the third straight year of declines for the butterflies that migrate from the United States to Canada after spending the winter in Mexico, scientists said this week.

Wilson points to dry conditions in Texas and Mexico as a key reason for the decline. He said it takes four generations of the insects to make it to Canada. He said the lack of milkweed plants along the way impedes their journey north from their breeding ground in Mexico.

"The severe drought in Texas and much of the Southwest continues to wreak havoc with the number of monarchs," he said.

Milkweed is the only type of plant the monarch will digest. Dry conditions and changing farming practices, such as an increased use of pesticides, have contributed to a drop in the growth of the plant. Texas' wildfires in recent years also hampered the growth of the plant.

Thirty types of milkweed grow in Texas, but currently the numbers cannot sustain the monarch's 2,000-mile migration to Canada.

"It is important to have a national priority of planting milkweed to assure there will be monarchs in the future," Wilson said. "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 said people can help by buying milkweed plants at a local farmer's market or grocery store and planting them.

The monarch even has won an endorsement from former President Jimmy Carter. He recently visited the monarch sites in Michoacan, where the insects breed during the winter, according to a statement released from Texas A&M.

"The monarch butterfly unites the three countries of North America in peace," Carter said in the statement. "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 is working on adding a variety of milkweed plants to a garden on Texas A&M's campus, the Cynthia Woods Mitchell Garden.