$2m to be spent on growing milkweed and other butterfly-friendly plants along main migration routes from Minnesota to Mexico as population slumps by 90%

This article is more than 5 years old

This article is more than 5 years old

The Obama administration and conservation groups launched a plan on Monday to halt the death spiral of the monarch butterfly.

The most familiar of American butterflies, known for their extraordinary migration from Mexico through the mid-west to Canada, monarch populations have plummetted 90% over the past 20 years.

Fewer than 50m butterflies made it to Mexico last winter – a fraction of the population once estimated at 1bn.

Those numbers mirror the sharp declines of honey bees in recent years.

“We need to turn that around,” Dan Ashe, director of US Fish and Wildlife Service, told the Guardian. “If you look at the 20-year trend definitely monarchs are at risk of vanishing.”

The USFWS will spend $2m (£1.3m) and work with the National Wildlife Federation and the National Fish and Wildlife Foundation to grow milkweed and other butterfly-friendly plants along the monarchs’ main migration routes from Minnesota to Mexico.

The initiative aims to restore more than 200,000 acres of habitat through the spring breeding grounds of Texas and Oklahoma and summer breeding areas in the Corn Belt, tracking closely to the I-35 highway from Austin, Texas to St Paul, Minnesota.

There are also plans to promote wildflowers such as goldenrod and aster along pipeline and electricity lines.

Monarch populations have fallen precipitously over the past 20 years because of changes in farming methods, and the destruction of milkweed that is the caterpillars’ main habitat.

The idea is to get populations back up to 1bn.

Monarchs showed a slight rebound this year, because of good weather. “That’s a sign we haven’t yet reached any disastrous tipping point,” Ashe said. “If the habitat improves, if we make more habitat for them, then the population still seems to have the ability to respond.”

The Centre for Biological Diversity went to court last August to seek protection for the monarch under the endangered species act. Ashe said the petition presented “substantive evidence” for such protections, and the government was studying the case.

Tracking the causes of monarch butterfly decline Read more

The centre welcomed the new initiative – but said protecting the monarchs would be far more effective.

“I think it’s great that this voluntary stuff is going to happen,” said Tierra Curry of the Centre for Biological Diversity. “But if the monarch does get protected that will open up a lot more funding to protect habitat.”

She went on: “It’s going to take a massive amount of investment and a massive amount of milkweed to reverse the decline.”