SANTA CRUZ >> The monarch butterfly is known for its spectacular 3,000-mile migration each year from Mexico to Canada and back.

“It’s a unique migration,” said Lincoln Brower, a biologist at Sweet Briar College and arguably the most established monarch butterfly expert. “Losing it will be like losing ‘Gone with the Wind’ or burning the Mona Lisa. It’s just an amazing, beautiful and complex phenomenon.”

Monarch populations have plummeted 90 percent during the last two decades. They have disappeared at such an alarmingly rate that they might become an endangered species.

U.S. Fish and Wildlife Service said this week that it would conduct a one-year status review of the monarch to determine whether it warranted Endangered Species Act protection.

The move came after conservationist groups filed a petition seeking federal protection.

“The monarch is one of our most famous, most well-known species of butterfly. People grew up with them,” said Sarina Jepsen, endangered species director with Xerces Society. “The fact that such a common species has undergone a decline this dramatic is indicative of the widespread landscape changes that we’re making for our environment.”

Scientists attribute farming practices, habitat loss and recent severe weather for the monarch’s sharp drop to 35 million butterflies last winter, the lowest number ever recorded. In the mid-1990s, the population was estimated at 1 billion butterflies.

Brower blames the use of pesticides and genetically engineered crops in the Midwest, where most monarchs are born. Chemical spray on crops has decimated milkweed plants, which the orange and black butterflies lay their eggs on and nourish their caterpillars.

“I think the importance of having the butterflies as a threatened species is calling attention to the plight that agriculture is doing in general,” Brower said.

In nearly two decades, scientists estimate that monarchs may have lost more than 165 million acres of habitat, an area about the size of Texas, and nearly a third of their summer breeding grounds.

Brower called Fish and Wildlife’s announcement a wakeup call.

“I hope it will be seen something far more important than the monarch itself,” he said. “This is a really amazing opportunity to call attention to catastrophic biodiversity loss.”

Most monarchs west of the Rocky Mountains winter along the California coast. Found in abundance at Pacific Grove and Natural Bridges State Beach, the colorful butterfly is an icon to the Monterey Bay Area.

But in 1997, more than 120,000 monarchs were counted at Natural Bridges. That number has declined to 3,400 in 2014, statistics show.

help the monarch

Native milkweeds are essential for monarch caterpillars. Planting milkweeds improves breeding habitat for the once-common black and orange butterfly.

To find for native milkweed seeds, visit www.xerces.org/milkweed-seed-finder.