Authorities who have struggled to stop illegal logging in Mexico's famed monarch butterfly reserve now are cutting down thousands of trees themselves to fight an unprecedented infestation of deadly bark beetles.
Biologists and park workers are racing to fell as many as 9,000
infected fir trees and bury or extract infested wood before the
orange-and-black monarchs start arriving in late October to spend
the winter bunched together on branches, carpeting the trees.
Environmentalists say the forest canopy of tall firs is
essential to shelter the butterflies on their annual migration
through Mexico, the United States and Canada. The journey is
tracked by scholars and schoolchildren across North America and
draws tens of thousands of tourists to the reserve, a U.N. Heritage
But freezing rains and cold night air that can kill the monarchs
at the high-altitude reserve, so the insects are threatened by a
loss of trees, whether by loggers or the bark beetles.
Because the migration is an inherited trait - no butterfly lives
to make the round-trip - it's not clear whether they could find
another wintering ground.
Experts say insecticide is the best way to control the beetles,
but that would endanger the butterflies. Instead, park officials
are fighting the plague tree-by-tree.
"It is obvious that in the medium and long term, if we do not
act to adapt to the changes, then there could be a serious risk"
to the butterflies' migration, said reserve director Rosendo Caro,
a forestry expert. "The forest is not going to disappear, but the
conditions that make up the right environment for the wintering
phenomenon could disappear."
Beetles are devastating forests across the continent from
Colorado to the Yukon, killing millions of acres (hectares) of
trees. In most places, the infestation is spurred by trees weakened
by drought, and beetles that thrive in warmer weather. The dead
trees increase the risk of forest fires, exacerbating the problem.
Bark beetles have long been present in the reserve monarch
reserve, usually attacking a few trees in the driest months of
early spring, before heavy seasonal rains that normally start in
May. But this year, little rain had fallen by July, and the trees
were weakened. The beetles took advantage, burrowing in and robbing
the trees of nutrients until they turned orange and die.
The infestation so far has affected 100 of the 13,550 hectares
(33,482 acres) in the reserve's core mountaintop wintering grounds.
But experts are concerned because the outbreak is occurring in
patches, indicating the infestation is spreading. And a Mexican
government report on climate change predicts more late or delayed
summer rains, with a 15 percent decline in overall rainfall between
now and 2080.
If the bark beetle attacks become a regular occurrence and more
trees are felled, Monarch expert Lincoln Brower worries there could
be more "holes in the blanket" of the tree canopy that protects
Diana Six, a professor of forest entomology and pathology at the
University of Montana, said the best way to protect trees is to
spray their bases with the pesticide Carbaryl, but "you can't use
it if you've got Monarchs coming in, because it's a general
pesticide; it kills everything as far as insects."
So Mexican officials face the time-consuming task of cutting
down each infested tree, removing the bark, burying it under soil,
and then taking away the wood to prevent the beetles from
spreading. Once the butterflies are back, the work must stop.
Caro said he thinks authorities have caught the problem in time
The die-off comes just as authorities were making headway
against illegal logging. Since 2006, armed police have patrolled to
combat logging gangs and aid for the mountain villages that dot the
reserve has helped reduce tree loss.
A report by the World Wildlife Fund and Mexican
environmentalists found that deforestation in the reserve declined
by about 44 percent, falling from about 460 hectares (1,136 acres)
in 2005-2006, to 260 hectares between 2007 and 2008. Mexican
officials say they would like to curb it even further, but the
problem is mainly confined to one small area.
Still, the prospect of reserve officials cutting down trees
worries some longtime defenders of the oyamel fir forest, like
"There is a frequent ploy to justify cutting oyamels and pines
by claiming bark beetle infestation," he noted.
Felipe Martinez, a biologist working on the anti-beetle effort,
says "not a single piece of wood" will be moved out of the
reserve unless environmental authorities authorize it.
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