Winter storm in Mexico kills 270 million monarch butterflies
http://startribune.com/stories/1551/1617116.html
New York Times (as published in the Minneapolis StarTribune newspaper)
After a severe storm in mid-January in the mountains of central
Mexico, dead monarch butterflies lay in piles that in some places
were more than a foot high. Researchers estimated that between 220
million and 270 million frozen butterflies had rained down from
roosts where they normally festooned towering trees.
"I've been going down there for 25 years and I've never seen
anything like it," said Lincoln Brower, a butterfly biologist.
Most of the monarchs in the two biggest colonies in Mexico were
killed in rain followed by freezing temperatures -- the largest known
die-off ever of these butterflies, according to a report by Brower
and a team of researchers from Mexico and the United States. But the
loss is not expected to threaten the species, they said.
In the report, Brower, of Sweet Briar College in Sweet Briar, Va.,
and his colleagues estimated that 74 percent of the monarchs at the
Sierra Chincua colony and 80 percent at the Rosario colony had been
killed. Along with a few smaller colonies, which scientists have not
surveyed, the butterflies in these major colonies make up the entire
breeding stock of monarchs for the eastern United States and Canada.
The spectacle of the monarchs' long and rugged mass migration north
from Mexico each spring has made the species a favorite of nature
lovers. The butterflies fly northward, stopping to lay eggs in the
southern United States. The monarchs that develop from those eggs
continue the journey, and by summer, butterflies reach as far north
as Canada. If those populations were to disappear, the mysteries of
that migration might never be solved.
While saying it was unlikely that a single event could ring the death
knell for the Mexican monarch populations, researchers said the
radically reduced number leaves the butterflies vulnerable to the
whims of weather and disease and to deforestation in and around their
winter resting grounds in Mexico.
Scientists noted that the species is not in danger since other,
smaller populations of monarchs that do not migrate to Mexico can be
found elsewhere, such as in the western United States. Scientists
will know in coming weeks how precarious the situation of the
devastated populations has become.
"A bad winter followed by a bad spring could be
catastrophic," said Karen Oberhauser, a monarch ecologist at the
University of Minnesota.
Casual observers are unlikely to notice an obvious drop in monarch
numbers this spring, in part because of the natural variability in
population size from year to year.
[.edu fair use, 2002]
http://startribune.com/stories/1551/1617116.html
New York Times (as published in the Minneapolis StarTribune newspaper)
After a severe storm in mid-January in the mountains of central
Mexico, dead monarch butterflies lay in piles that in some places
were more than a foot high. Researchers estimated that between 220
million and 270 million frozen butterflies had rained down from
roosts where they normally festooned towering trees.
"I've been going down there for 25 years and I've never seen
anything like it," said Lincoln Brower, a butterfly biologist.
Most of the monarchs in the two biggest colonies in Mexico were
killed in rain followed by freezing temperatures -- the largest known
die-off ever of these butterflies, according to a report by Brower
and a team of researchers from Mexico and the United States. But the
loss is not expected to threaten the species, they said.
In the report, Brower, of Sweet Briar College in Sweet Briar, Va.,
and his colleagues estimated that 74 percent of the monarchs at the
Sierra Chincua colony and 80 percent at the Rosario colony had been
killed. Along with a few smaller colonies, which scientists have not
surveyed, the butterflies in these major colonies make up the entire
breeding stock of monarchs for the eastern United States and Canada.
The spectacle of the monarchs' long and rugged mass migration north
from Mexico each spring has made the species a favorite of nature
lovers. The butterflies fly northward, stopping to lay eggs in the
southern United States. The monarchs that develop from those eggs
continue the journey, and by summer, butterflies reach as far north
as Canada. If those populations were to disappear, the mysteries of
that migration might never be solved.
While saying it was unlikely that a single event could ring the death
knell for the Mexican monarch populations, researchers said the
radically reduced number leaves the butterflies vulnerable to the
whims of weather and disease and to deforestation in and around their
winter resting grounds in Mexico.
Scientists noted that the species is not in danger since other,
smaller populations of monarchs that do not migrate to Mexico can be
found elsewhere, such as in the western United States. Scientists
will know in coming weeks how precarious the situation of the
devastated populations has become.
"A bad winter followed by a bad spring could be
catastrophic," said Karen Oberhauser, a monarch ecologist at the
University of Minnesota.
Casual observers are unlikely to notice an obvious drop in monarch
numbers this spring, in part because of the natural variability in
population size from year to year.
[.edu fair use, 2002]