MONARCH COUNT REMAINS LOW
Disappointing results prompt some to action
PACIFIC GROVE >> For the second straight year, population counts of western monarch butterflies have registered their largest declines since continuous monitoring began more than 20 years ago. Part of a larger trend of worldwide insect loss, their disappearance is prompting a flutter of local activity among scientists and advocates.
“The cumulative impact of so many stressors was a tipping point that caused a year of collapse,” said Dan Kaiser, Director of Western Conservation Strategies for the Environmental Defense Fund. “Unfortunately, it’s just part of the larger story of biodiversity decline and insect declines around the world.”
Monarchs in California form a distinct group from the larger, eastern population. Separated by the spine of the Rocky Mountains, the two clusters have different migration routes. While eastern monarchs pass through the central U.S. to overwinter in Mexico, western monarchs ride out the cold in coastal California between Mendocino County and Baja California.
The Xerces Society coordi
nates groups of volunteers to perform annual counts throughout the western range each Thanksgiving. During the 2017 count, volunteers reported a total of 192,668 butterflies across 263 sites — itself a gradual decline of more than 90% from historical populations in the millions.
The following year, however, something particularly shocking happened.
Results from 2018 tallied only 28,429 butterflies, a decline of 86% in a single year and of 99.4% since the 1980s. By their estimates, only one butterfly remains alive today for every 160 in the past, placing the species below a critical threshold of 30,000 needed to guard against extinction.
This year, the number of monarchs visiting overwintering sites totaled only 29,418, another disappointingly low count. The situation has become so dire that the U.S. Department of Fish and Wildlife Services has been petitioned to list the species as endangered.
“Western monarchs are in big trouble,” Emma Pelton, the western monarch project lead for Xerces, said in a press release this week. “While it is encouraging that the population did not shrink any further, the population continues to hover just below the minimum threshold.”
In Pacific Grove, the Monarch Sanctuary counts likewise dropped an order of magnitude, from 7,350 in 2017 to 815 in 2018. In the most recent release, the Sanctuary reported only 642 butterflies.
Juan Govea, Director of Community Engagement at the Pacific Grove Museum of Natural History, oversees the local counts alongside Xerces and has been on hand to experience the loss.
“Last year was obviously really shocking and incredibly depressing,” Govea said. “But it prompts a lot of questions. When you’re looking at monarch butterfly numbers, you’re not looking at just a Pacific Grove problem, you’re looking at a global problem.”
The causes are complex and are likely the result of multiple stresses acting together. But common reasons include the loss of native milkweed habitat, the widespread use of pesticides and herbicides and more nuanced impacts brought on by climate change that knock the monarch out of sync with its natural life cycle.
Monarch butterflies will only lay their eggs on milkweed, a tall and leafy plant with clusters of bright flowers. Generally considered nuisance plants with little economic value, milkweed has been reduced through aggressive herbicide and pesticide usage, a threat that affects insects worldwide.
But not all milkweed is the same, and even the little that remains might not be the best habitat. Native milkweeds that typically die off in the winter have been supplanted by non-native species that exist yearround. When monarchs encounter them, they start mating when they should be resting. Govea shared anecdotal evidence of seeing monarch caterpillars this winter in Pacific Grove, something he says “should not be happening.”
In addition, those monitoring the migrations have noted more butterflies arriving later in the fall and leaving earlier in the spring as temperature cues shift under warming conditions. A monarch leaving earlier in the spring may find that no milkweed has grown. Kaiser calls it “the classic example of a species getting an early migratory signal that’s altered because of climate change before the plants can adapt.”
While the issue is complex, there is nevertheless a strong base of support for ongoing action.
“What’s really different about monarchs is the universal appeal and response from all kinds of sectors: politicians, agricultural associations, farmers, and regular citizens,” Kaiser said. “They all want to do something.”
To draw on that support, Kaiser organized a workshop at UC Davis in February 2019, bringing together various groups working in the monarch conservation space. He also helped establish the Monarch Butterfly and Pollinator Rescue Program under California’s AB 2421 which provided $3 million in funding for ongoing conservation efforts.
More recently, the Oregon-based non-profit Western Monarch Advocates formed to put together a Western Monarch Summit, held earlier this month in Carmel. The inaugural event drew over 160 presenters from across the country, including Xerces Society founder Robert M. Pyle.
Robert Coffan, the nonprofit’s chair, said he was “astonished at the obvious need for the eastern and western folks to get together and talk.” Together, each sector offers a fuller view of what can be done in the future. Changes are being discussed on a local, regional and national scale.
And on the Monterey Peninsula, it isn’t only professionals taking action. Jackson Swette, a high school student at Stevenson High School in Pebble Beach, was prompted to start his own non-profit, The Monterey Monarch Project, after reading local coverage of the 2018 declines.
“I had a realization that if I wasn’t going to help and do anything about it there is a high chance that very few others would,” Swette said. “It was a very spontaneous decision for me, as this is something that I normally would not do.”
Swette is working with local schools and businesses to establish “monarch waystations,” spaces of refuge planted with thousands of native milkweeds and flowering plants. In particular, he is focusing on “energizing and engaging young people,” educating them on best practices.
The Peninsula is a rarified, essential monarch habitat. But well-meaning residents can do unintentional harm if they fail to follow certain rules.
For example, milkweed should never be planted within 5-10 miles of the coast, where the majority of overwintering sites are located. Instead, planting native, nectar-producing plants that bloom in late fall for returning butterflies as well as in early spring for those setting out to breed will provide a needed boost of fuel at delicate moments in a monarch’s life.
However, anyone living more than 10 miles from the coast — especially in the Salinas and Central Valleys and in the Sierra foothills — should plant milkweed along with nectar-producing plants. Native, climateappropriate species such as the Narrow Leaf and Showy Milkweed are best.
And of course, limiting the usage of pesticides and herbicides in gardens and crops will help not only monarchs but other insects as well. While the monarch has captured the public imagination, it is one of more than 150 native California butterflies experiencing declines of greater than 50%. A further 40% of insects worldwide are plummeting, a phenomenon known as the “Insect Apocalypse.”
“Learning about the monarch, you really learn about all the native pollinators and insects that are in trouble,” Kaiser said. “But working on this campaign has made me optimistic about just how much people care about biodiversity.”