Quantcast

Monarch Butterfly Population Plummets in California

Animals
Monarch butterfly on swamp milkweed. Jim Hudgins / USFWS

The population of monarch butterflies that spend winter along the California coast dropped 86 percent since 2017, according to a recent count by the Xerces Society, an invertebrate conservation group.

Preliminary results from the Western Monarch Thanksgiving Count, an annual citizen science program, recorded less than 30,000 butterflies overwintering in California, a significant decline from the estimated 192,000 in 2017. The official numbers will be released later this month.


Emma Pelton, a Xerces Society endangered species conservation biologist, wrote in a blog post that the initial results are "disturbingly low" and perhaps "catastrophic."

"While overwintering populations naturally fluctuate, even by double digit percentages, the magnitude of this year's drop is of significant concern because the monarch population was already at a new low after the 97 percent decline it has experienced since the 1980s ( Schultz et al. 2017), leading to a situation which may be catastrophic for the western population," Pelton wrote.

The 30,000 butterflies counted is the average quasi-extinction population size—or "the number of adult butterflies needed to ensure persistence of the western monarch population," Pelton explained.

It is not yet clear why their numbers were so low in 2018, although prolonged drought, a late rainy season, as well as smoke and poor air quality caused by the region's devastating wildfires could be to blame, Pelton suggested.

The latest count adds to more bad news for the iconic species, whose numbers have precipitously declined.

"In my lifetime, the monarch population in California has gone from millions of butterflies to hundreds of thousands and now, possibly, mere tens of thousands," Pelton wrote, noting that one study estimated 4.5 million monarchs overwintering in California in the 1980s.

"Next year will be a real test in how resilient the western monarch population is, after its California overwintering population has been reduced to less than 0.5 percent of its historical size," she added.

Scientists warn that the black-and-orange butterflies—known for their annual, 3,000-mile migration from the U.S. and Canada to Mexico—is at risk of extinction.

Overall, the monarch population has dropped by more than 80 percent over the past two decades. Their disappearance has been linked to climate change, habitat loss, pesticides and reduced milkweed, a native wildflower and main food source for monarch caterpillars and the only plant on which adult monarchs lay their eggs.

Despite the grim report, there are ways you can help the survival of the beloved species, which are also crucial pollinators for many different kinds of wildflowers.

"While western monarchs are facing unprecedented challenges right now, there is still hope that we can recover the population if we work quickly, strategically and together," Pelton said.

Learn more about how you can help.

EcoWatch Daily Newsletter

California Condor at soaring at the Grand Canyon. Pavliha / iStock / Getty Images

North America's largest bird passed an important milestone this spring when the 1,000th California condor chick hatched since recovery efforts began, NPR reported Sunday.

Read More Show Less
The Roloway monkey has been pushed closer to extinction. Sonja Wolters / WAPCA / IUCN

The statistics around threatened species are looking grim. A new report by the International Union for Conservation of Nature (IUCN) has added more than 9,000 new additions to its Red List of threatened species, pushing the total number of species on the list to more than 105,000 for the first time, according to the Guardian.

Read More Show Less
Sponsored
Golde Wallingford submitted this photo of "Pure Joy" to EcoWatch's first photo contest. Golde Wallingford

EcoWatch is pleased to announce our third photo contest!

Read More Show Less
BRENDAN SMIALOWSKI / AFP / Getty Images

The campaign to re-elect President Donald Trump has found a new way to troll liberals and sea turtles.

Read More Show Less
Night long exposure photograph of wildifires in Santa Clarita, California. FrozenShutter / E+ / Getty Images

By Kristy Dahl

Last week, UCS released Killer Heat, a report analyzing how the frequency of days with a dangerously hot heat index — the combination of temperature and humidity the National Weather Service calls the "feels like" temperature — will change in response to the global emissions choices we make in the coming decades.

Read More Show Less
Sponsored
A Zara store in Times Square, Causeway Bay, Hong Kong. Timahaowemi / CC BY-SA 3.0

Green is the new black at Zara.

The Spanish fast fashion behemoth has made a bold move to steer its industry to a more environmentally friendly future for textiles. Inditex, Zara's parent company, announced that all the polyester, cotton and linen it uses will be sustainably produced by 2025, as CNN reported.

Read More Show Less
Pexels

By Gavin Van De Walle, MS, RD

Whether you enjoy running recreationally, competitively, or as part of your overall wellness goals, it's a great way to improve your heart health.

Read More Show Less
Text from the plaque that will mark the site where Ok glacier once was. Rice University

By Andrea Germanos

A climate change victim in Iceland is set to be memorialized with a monument that underscores the urgent crisis.

Read More Show Less