New Jersey is seeing a decline in Monarch butterflies. Here’s what the state is doing to make sure these beauties stick around.
The number of monarch butterflies that overwintered in forests in Mexico fell for a second straight year, experts say.
Monday’s count of 6.12 acres of winter habitat is down from the 7.19 acres last winter.
Monarch populations are measured by the number of acres of trees occupied by clustering butterflies that spend the winter in Mexico.
“The decrease is attributed to the presence of two tropical storms and three hurricanes that hit the Atlantic coasts in mid-September 2017 when migration begins,” said Jorge Rickards, head of the World Wildlife Fund in Mexico. “This impacted the number of Monarchs that arrived in Mexico.”
Unusually warm temperatures in the U.S. Midwest and Northeast also caused a late migration and resulted in low occupancy areas in Mexico, Rickards said.
After spending the winter in Mexico, the monarchs flap their way north into the USA and Canada in the spring and summer. No single butterfly finishes the entire journey; it takes a few generations to complete the trip. In the spring and summer, the monarchs live only about 2-5 weeks.
A final generation then migrates back south to Mexico in the fall to start the cycle over again.
The number of monarchs that overwinter in Mexico is far below what they were in past years: There has been a decline of more than 80% over the past 20 years. Two decades ago, the butterflies occupied as many as 44 acres of trees, according to Monarch Watch.
In addition to bad weather, illegal logging and habitat destruction are the main threats to the butterflies, according to Rickards. “But how many monarch butterflies arrive to hibernate to the mountains of Mexico depend on how many can survive during their migration route in the United States, Canada and Mexico,” he said.
Increased use of herbicides in the U.S. have hurt the prevalence of milkweed, which monarch caterpillars feed on, risking their survival, the Associated Press said.
“We could lose the monarch butterfly if we don’t take immediate action to rein in pesticide use and curb global climate change,” said Tierra Curry, a senior scientist with the Center for Biological Diversity.
A 2016 study by the U.S. Geological Survey concluded that because of ongoing low population levels, there is an 11% to 57% risk that the eastern monarch migration could collapse within the next 20 years.
“Another year, another reminder: Our government must do what the law and science demands and protect monarchs under the Endangered Species Act, before it’s too late,” said George Kimbrell, legal director with the Center for Food Safety.
The U.S. Fish and Wildlife Service’s initial decision was that endangered species protection may be warranted for the monarch. A final decision should be made by June 2019.
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