The recent snowfall registered in the country that brought temperatures of 12˚Celsius below zero in some regions killed almost 1.5 million monarch butterflies who were hibernating in national territory.
The figures come on the heels of authorities’ assurance that the butterflies had braved the harsh climes. Yesterday a video was released showing butterflies still alive, clinging to branches.
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According to the Rosario sanctuary, these figures are around 3 percent of he 50 million lepidopterans that arrived at the nature reserve this season. They have confirmed that many are still breathing and will be able to fly once the sun melts the snow.
This week’s extreme weather brought up to 35 centimeters of snow, snow banks, hail and winds up to 80 kilometers an hour, which also caused dozens of trees within the reserve to fall.
The butterflies are starting the process of returning on their annual migration to the U.S. and Canada.
Authorities said in February that the monarchs have made a big comeback after suffering serious declines. The area covered by the orange-and-black insects this season was more than three and a half times greater than the previous winter. The butterflies clump so densely in the pine and fir forests they are counted by the area they cover rather than by individual insects.
The number of monarchs making the 3,400-mile (5,500-kilometer) migration from the United States and Canada declined steadily in recent years before recovering in 2014. This winter was even better.
This December, the butterflies covered 10 acres (about 4 hectares), compared to 2.8 acres (1.13 hectares) in 2014 and a record low of 1.66 acres (0.67 hectares) in 2013.
Illegal logging remains a problem Mexico’s monarch wintering grounds. It more than tripled in 2014, reversing several years of steady improvements. Illegal logging had fallen to almost zero in 2012.
Authorities said the reserve’s buffer area lost more than 22 acres (9 hectares) in 2015 due to illegal logging in one area, but said the tree cutting was detected and several arrests were made.
The forest canopy acts as a blanket against the cold for butterflies.
WITH ADDITIONAL INFORMATION FROM THE ASSOCIATED PRESS