Mexico storm may have wiped out 50 percent of monarch population

Monarch butterfly

Despite earlier reports indicating that dwindling monarch butterfly populations were on the upswing, researchers are now saying otherwise.

A late winter storm that ravaged the region of Mexico where monarchs over-winter left a huge portion of the butterflies frozen to trees or dead on the ground.

Nothing is confirmed yet, but reports say the storm could have wiped out up to 50 percent of the population, and Monarch Watch—a network of students, teachers, and volunteers dedicated to studying the butterfly—described the storm as “unprecedented.”

“Right now, it certainly looks like it’s going to be a much lower population,” Chip Taylor, founder of Monarch Watch and a professor at the University of Kansas, told CBC News.

Journey North, another project designed to track monarchs, recorded numbers for this year’s “first sightings” that match the all-time lows seen in 2013.

It’s unfortunate news, especially since the huge amount of work that’s been put into regenerating the population—like reintroducing milkweed and designating pesticide-free areas throughout the continent—appeared to be working. The number of butterflies making the trip to Mexico was on a steady decline until 2013, when the they covered less than one hectare of the fir-tree covered mountains northwest of Mexico City. But over the past two years, things looked promising, as the numbers rose to 1.13 hectares in 2014 and nearly four hectares in 2015.

But Taylor assured reporters that “first sightings are an imperfect indicator of what to expect for the rest of the season,” which one reason he isn’t disheartened by the news.

He also noted that restoring this population isn’t going to happen overnight, and that storms like these are just one of the many problems monarchs are going to face along the way.

“Restoration projects are a long haul type of thing. We’re not talking about instant gratification,” he told CBC while on his way to plant milkweed in Oklahoma on Friday. “We’re talking about a decade or more to bring this butterfly back.”

Although the US successfully restored approximately 100,000 hectares of milkweed in just one year, 1 billion stems have been lost along the butterflies’ summer breeding range, due to herbicides and urban sprawl. The key is to continue positive efforts like planting milkweed, establishing more area for the butterflies to breed and find food. And of course, to just be patient.

In the meantime, researchers should have a better sense of how the population is developing by early June, if not later this month.