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RISK ASSESSMENT & TECHNOLOGY: Mexico monarch butterfly population smallest in years due to loss of milkweed by glypohosate use



                                  PART 1


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TITLE:   MEXICO MONARCH BUTTERFLY POPULATION SMALLEST IN YEARS, STUDY SAYS

SOURCE:  Los Angeles Times, USA

AUTHOR:  Richard Fausset

URL:     http://articles.latimes.com/2013/mar/13/world/la-fg-mexico-butterflies-20130314

DATE:    13.03.2013

SUMMARY: "cientists who take the annual measure of Mexican forestland famously occupied by migrating monarch butterflies said Wednesday that the butterfly population is the smallest they have seen in two decades. [...] Taylor said the decline is due in great part to the widespread use of the herbicide glyphosate. In key U.S. states where the butterfly feeds and breeds ? Iowa, Minnesota, Wisconsin, Illinois, Indiana, parts of Ohio and the eastern Dakotas ? farmers have planted more than 120 million acres of corn and soybeans genetically modified to resist the herbicide, he said. That allows them to use glyphosate to kill milkweed, the monarchs? essential food."

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MEXICO MONARCH BUTTERFLY POPULATION SMALLEST IN YEARS, STUDY SAYS

The amount of land occupied by the migrating creatures shrank 59% from a year ago, scientists say. The decline could hurt tourism and the ecosystem.

MEXICO CITY ? Scientists who take the annual measure of Mexican forestland famously occupied by migrating monarch butterflies said Wednesday that the butterfly population is the smallest they have seen in two decades.

The likely cause is unseasonably warm weather recently in the United States, as well as a dramatic loss of habitat in the U.S. Corn Belt, the scientists said.

In a survey carried out in December and January, researchers found nine monarch colonies wintering in central Mexico, occupying a total of 1.19 hectares, or 2.94 acres, a 59% decrease compared with the previous year?s study.

It was troubling news for the Mexican states of Michoacan and Mexico, where the yearly arrival of the butterflies is a major tourist attraction. Of even greater concern, experts say, is the potential impact that a diminished butterfly population could have on interconnected habitats and species across North America.

The results were released by the World Wildlife Fund, the Mexican government and giant Mexican cellphone company Telcel, which has supported butterfly habitat conservation.

The measurements do not mean that the Mexican habitat is disappearing; rather, measuring the area that the butterflies occupy is the best way to estimate their numbers. Precise figures are hard to come by, but 1 hectare may contain as many as 50 million butterflies.

The yearly figures can fluctuate greatly because of variations in the weather. But Chip Taylor, director of the research group Monarch Watch at the University of Kansas, said the numbers have generally been trending downward.

Taylor said the decline is due in great part to the widespread use of the herbicide glyphosate. In key U.S. states where the butterfly feeds and breeds ? Iowa, Minnesota, Wisconsin, Illinois, Indiana, parts of Ohio and the eastern Dakotas ? farmers have planted more than 120 million acres of corn and soybeans genetically modified to resist the herbicide, he said. That allows them to use glyphosate to kill milkweed, the monarchs? essential food.

Taylor said the decrease in the monarch population is more than a philosophical or aesthetic conundrum. The loss of pollinating creatures like butterflies and bees ? whose populations are also collapsing because of habitat loss ? can result in a loss of plant diversity across the continent, he said.

?The fruits, nuts, seeds and foliage that everything else feeds on,? he said. ?If we pull the monarchs out of the system, we?re really pulling the rug out from under a whole lot of other species.?

The dramatic winter presence of tens of millions of hibernating monarchs about two hours? drive northwest of Mexico City was little known outside the region until 1975, when the monarchs were ?discovered? by a Canadian zoologist. The Mexican government created a biosphere to protect the insects in 1986.

The butterflies make their way from the U.S. and Canada, usually arriving in Mexico around the beginning of November, clustering by the thousands in the boughs of fir trees. Although the same trip occurs every year, no individual butterfly makes it twice, as the butterfly?s life span is too short. How the migration route lives on in the butterflies? collective memory is an enduring scientific mystery.

In Mexico, the government and some nonprofit organizations have worked to discourage illegal logging and encourage tourism that will not harm the butterflies. In the United States, Monarch Watch encourages gardeners to purchase $16 seed kits for growing milkweed and nectar plants the butterflies need. The seeds have been planted in more than 6,000 areas certified by the group as monarch ?waystations? since 2005.

Taylor said Monarch Watch is working on broader-scale solutions, including a system of getting large numbers of milkweed plants to native plant societies and other conservation groups around the U.S.



                                  PART 2

------------------------------- GENET-news -------------------------------

TITLE:   NUMBER OF MONARCH BUTTERFLIES DROP BY ?OMINOUS? 59 PERCENT IN MEXICO RESERVE, EXPERTS REPORT

SOURCE:  The Washington Post, USA

AUTHOR:  The Associated Press, USA

URL:     http://www.washingtonpost.com/world/the_americas/number-of-monarch-butterflies-drop-by-ominous-59-percent-in-mexico-reserve-experts-report/2013/03/13/8ebc15ea-8c3a-11e2-adca-74ab31da3399_print.html

DATE:    13.03.2013

SUMMARY: "The number of Monarch butterflies making it to their winter refuge in Mexico dropped 59 percent this year, falling to the lowest level since comparable record-keeping began 20 years ago, scientists reported Wednesday. It was the third straight year of declines for the orange-and-black butterflies that migrate from the United States and Canada to spend the winter sheltering in mountaintop fir forests in central Mexico. Six of the last seven years have shown drops, and there are now only one-fifteenth as many butterflies as there were in 1997. The decline in the Monarch population now marks a statistical long-term trend and can no longer be seen as a combination of yearly or seasonal events, the experts said."

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NUMBER OF MONARCH BUTTERFLIES DROP BY ?OMINOUS? 59 PERCENT IN MEXICO RESERVE, EXPERTS REPORT

MEXICO CITY ? The number of Monarch butterflies making it to their winter refuge in Mexico dropped 59 percent this year, falling to the lowest level since comparable record-keeping began 20 years ago, scientists reported Wednesday.

It was the third straight year of declines for the orange-and-black butterflies that migrate from the United States and Canada to spend the winter sheltering in mountaintop fir forests in central Mexico. Six of the last seven years have shown drops, and there are now only one-fifteenth as many butterflies as there were in 1997.

The decline in the Monarch population now marks a statistical long-term trend and can no longer be seen as a combination of yearly or seasonal events, the experts said.

But they differed on the possible causes.

Illegal logging in the reserve established in the Monarch wintering grounds was long thought to contribute, but such logging has been vastly reduced by increased protection, enforcement and alternative development programs in Mexico.

The World Wildlife Fund, one of the groups that sponsored the butterfly census, blamed climate conditions and agricultural practices, especially the use of pesticides that kill off the Monarchs? main food source, milkweed. The butterflies breed and live in the north in the summer, and migrate to Mexico in the winter.

?The decrease of Monarch butterflies ... probably is due to the negative effects of reduction in milkweed and extreme variation in the United States and Canada,? the fund and its partner organizations said in a statement.

Omar Vidal, the World Wildlife Fund director in Mexico, said: ?The conservation of the Monarch butterfly is a shared responsibility between Mexico, the United States and Canada. By protecting the reserves and having practically eliminated large-scale illegal logging, Mexico has done its part.?

?It is now necessary for the United States and Canada to do their part and protect the butterflies? habitat in their territories,? Vidal said.

Logging was once considered the main threat to the reserve, located west of Mexico City. At its peak in 2005, logging devastated as many as 1,140 acres (461 hectares) annually in the reserve, which covers 193,000 acres (56,259-hectares). But a 2012 aerial survey showed almost no detectable logging, the first time that logging had not been found in detectable amounts since the mountaintop forests were declared a nature reserve in 2000.

The loss of milkweed in the Monarchs? summering areas in the north can make it hard for the butterflies to lay eggs, and for the offspring that do hatch to find enough food to grow to maturity. In addition, unusually hot or dry weather can kill eggs, meaning fewer adult butterflies. For butterflies that reach adulthood, unusual cold, lack of water or tree cover in Mexico can mean they?re less likely to survive the winter.

Lincoln Brower, a leading entomologist at Sweet Briar College in Virginia, said in a statement that ?the report of the dwindling Monarch butterfly winter residence in Mexico is ominous.?

?This is not just the lowest population recorded in the 20 years for which we have records,? Brower said. ?It is the continuation of a statistically significant decrease in the Monarch population that began at least a decade ago.?

However, Brower differed on whether small-scale logging, the diversion of water resources and other disruptive activity in the reserves in Mexico are playing a role in the decline.

?To blame the low numbers of monarchs solely on what is happening north of Mexico is misleading,? Brower said. ?Herbiciding of soybean and corn fields that kills milkweed is a serious problem, but the historical decline over the past 19 years has multiple causes.?

?All three countries need to face up to the fact that it is our collective activities that are killing the migratory phenomenon of the Monarch butterfly,? he said.

Homero Aridjis, a writer and environmentalist, said, ?The decline in butterflies in the ?Mexico) reserve is truly alarming.?

Aridjis is from Contepec, a town in Michoacan state where Monarchs used to appear in the fall but don?t show up anymore. Six other communities in and around the reserve that once had butterflies saw no detectable numbers this year. Aridjis cited a lack of control on tourists, crime in the area and small-scale logging as threats to the reserve.

The head of Mexico?s nature reserves, Luis Fueyo, said there are still some problem to be solved at the wintering grounds in Mexico, including some scale-logging and water availability. The Monarchs don?t drink any water throughout their long migration until the reach Mexico, and the mountain streams in the area have been affected by drought and human use.

The migration is an inherited trait. No butterfly lives to make the round-trip. The millions of Monarchs cluster so densely on tree boughs in the reserve that researchers don?t count their individual numbers but rather measure the amount of forest they cover.

This winter, the butterflies covered just 2.93 acres (1.19 hectares), down from 7.14 acres (2.89 hectares) last year.



                                  PART 3

------------------------------- GENET-news -------------------------------

TITLE:   MONARCH MIGRATION PLUNGES TO LOWEST LEVEL IN DECADES

SOURCE:  The New York Times, USA

AUTHOR:  Michael Wines

URL:     http://www.nytimes.com/2013/03/14/science/earth/monarch-migration-plunges-to-lowest-level-in-decades.html?_r=1&;

DATE:    13.03.2013

SUMMARY: "The number of monarch butterflies that completed an annual migration to their winter home in a Mexican forest sank this year to its lowest level in at least two decades, due mostly to extreme weather and changed farming practices in North America, the Mexican government and a conservation alliance reported on Wednesday.

The area of forest occupied by the butterflies, once as high at 50 acres, dwindled to 2.94 acres in the annual census conducted in December, Mexico?s National Commission of Natural Protected Areas disclosed at a news conference in Zitácuaro, Mexico. That was a 59 percent decline from the 7.14 acres of butterflies measured in December 2011."

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MONARCH MIGRATION PLUNGES TO LOWEST LEVEL IN DECADES

The number of monarch butterflies that completed an annual migration to their winter home in a Mexican forest sank this year to its lowest level in at least two decades, due mostly to extreme weather and changed farming practices in North America, the Mexican government and a conservation alliance reported on Wednesday.

The area of forest occupied by the butterflies, once as high at 50 acres, dwindled to 2.94 acres in the annual census conducted in December, Mexico?s National Commission of Natural Protected Areas disclosed at a news conference in Zitácuaro, Mexico.

That was a 59 percent decline from the 7.14 acres of butterflies measured in December 2011.

Because the insects cannot be counted, the combined size of the butterfly colonies is used as a proxy in the census, which is conducted by the commission and a partnership between the World Wildlife Fund and the Mexican cellphone company Telcel.

?We are seeing now a trend which more or less started in the last seven to eight years,? Omar Vidal, the head of the wildlife group?s Mexico operations, said in an interview. Although insect populations can fluctuate greatly even in normal conditions, the steady downward drift in the butterfly?s numbers is worrisome, he said.

The latest decline was hastened by drought and record-breaking heat in North America when the monarchs arrived last spring to reproduce. Warmer than usual conditions led the insects to arrive early and to nest farther north than is typical, Chip Taylor, director of the conservation group Monarch Watch at the University of Kansas, said in an interview. The early arrival disrupted the monarchs? breeding cycle, he said, and the hot weather dried insect eggs and lowered the nectar content of the milkweed on which they feed.

That in turn weakened the butterflies and lowered the number of eggs laid.

But an equally alarming source of the decline, both Mr. Taylor and Mr. Vidal said, is the explosive increase in American farmland planted in soybean and corn genetically modified to tolerate herbicides.

The American Midwest?s corn belt is a critical feeding ground for monarchs, which once found a ready source of milkweed growing between the rows of millions of acres of soybean and corn. But the ubiquitous use of herbicide-tolerant crops has enabled farmers to wipe out the milkweed, and with it much of the butterflies? food supply.

?That habitat is virtually gone. We?ve lost well over 120 million acres, and probably closer to 150 million acres,? Mr. Taylor said.

A rapid expansion of farmland ? more than 25 million new acres in the United States since 2007 ? has eaten away grasslands and conservation reserves that supplied the monarchs with milkweed, he said.

The monarchs? migration is seen as a natural marvel and, for Mexico, a huge tourist attraction. But naturalists regard the butterflies as a forward indicator of the health of the food chain. Fewer butterflies probably means there are fewer other insects that are food for birds, and fewer birds for larger predators.

Mr. Vidal and Mr. Taylor said December?s record-low census does not necessarily constitute a knockout blow against the butterfly. The Mexican government has halted what was once extensive logging in the monarchs? winter home, and there remains the prospect that conservationists and state and local governments will replenish some of the milkweed lost to development and changed farming habits.

Mr. Vidal said that American and Canadian officials should move quickly. ?Mexico is doing its part,? he said. ?Mexico has invested resources, and it?s eliminated this massive illegal logging in the reserve. But on the other hand, I think the United States has to do much more.?

Mr. Taylor said a further decline could cross a tipping point at which the insects will be unusually vulnerable to outside events like a Mexican cold snap or more extreme heat that could put them in peril.

?Normally, there?s a surplus of butterflies and even if they take a big hit, they recover,? he said. But if their current 2.94-acre wintering ground drops below 2.5 acres, bouncing back could be difficult.

?This is one of the world?s great migrations,? he said. ?It would be a shame to lose it.?