Butterfly count in Mexico reveals bleak winter for monarchs
This is the worst year on record for the monarch butterfly, with North America’s entire population of the orange insects now squeezed into less than one hectare in Mexico.
The monarchs spend winter packed together in a remote forest of the Mexican mountains, and researchers have been measuring how much land they occupy each year since 1994. A bigger area means more monarchs.
Numbers jump up and down a lot, but not like this: The butterflies occupied between five and 20 hectares most of the time from 1994 to 2004. Since then, their colony has been shrinking.
Last year, at 1.19 hectares, was considered a disaster. This winter’s cluster is just over half that size: 0.67 ha.
At the University of Ottawa, biologist and butterfly specialist Jeremy Kerr was stunned by the news.
“That’s the worst!” he said as the figures were read out to him.
“We’re talking about a twentieth” of the population from the 1990s, when measurements began, he said. “Or not even” a twentieth.
“There’s a 20-year very strong trend for declining.”
Butterfly numbers always “bounce around a little” between good and bad years, he said. “The problem is that it’s hard to escape once you’re in this kind of vortex. They’ve been hit by a bunch of different things in a bunch of different places, and they’re all bad.”
Farm pesticides in their main flyway through the United States and into Canada are one hazard, he said. The conservation group Monarch Watch also blames herbicide-resistant crops, which allow farmers to do a better job of killing weeds, including milkweed, the monarchs food source.
As well, the abnormally hot spring of 2012 sent many migrating too far north, Kerr said. He doubts any of those survived to return south.
Last month, the leaders of Canada, the United States and Mexico held a summit in Mexico and pledged to establish a working group to ensure the conservation of the monarch, calling it “a species that symbolizes our association.”
This came after scientists, environmentalists, writers and artists asked them to create a north-south corridor of milkweed and reverse declines in butterfly populations.
It takes several generations of butterflies, each living a few weeks, to migrate from Mexico to Canada. Butterflies born in Canada then head south in late summer.
Kerr said there are “serious and acute concerns that this butterfly’s astonishing annual migration event could be fading away.”
The monarchs spend winter packed together in a remote forest of the Mexican mountains, and researchers have been measuring how much land they occupy each year since 1994. A bigger area means more monarchs.
Numbers jump up and down a lot, but not like this: The butterflies occupied between five and 20 hectares most of the time from 1994 to 2004. Since then, their colony has been shrinking.
Last year, at 1.19 hectares, was considered a disaster. This winter’s cluster is just over half that size: 0.67 ha.
At the University of Ottawa, biologist and butterfly specialist Jeremy Kerr was stunned by the news.
“That’s the worst!” he said as the figures were read out to him.
“We’re talking about a twentieth” of the population from the 1990s, when measurements began, he said. “Or not even” a twentieth.
“There’s a 20-year very strong trend for declining.”
Butterfly numbers always “bounce around a little” between good and bad years, he said. “The problem is that it’s hard to escape once you’re in this kind of vortex. They’ve been hit by a bunch of different things in a bunch of different places, and they’re all bad.”
Farm pesticides in their main flyway through the United States and into Canada are one hazard, he said. The conservation group Monarch Watch also blames herbicide-resistant crops, which allow farmers to do a better job of killing weeds, including milkweed, the monarchs food source.
As well, the abnormally hot spring of 2012 sent many migrating too far north, Kerr said. He doubts any of those survived to return south.
Last month, the leaders of Canada, the United States and Mexico held a summit in Mexico and pledged to establish a working group to ensure the conservation of the monarch, calling it “a species that symbolizes our association.”
This came after scientists, environmentalists, writers and artists asked them to create a north-south corridor of milkweed and reverse declines in butterfly populations.
It takes several generations of butterflies, each living a few weeks, to migrate from Mexico to Canada. Butterflies born in Canada then head south in late summer.
Kerr said there are “serious and acute concerns that this butterfly’s astonishing annual migration event could be fading away.”
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