Pismo Beach’s monarch butterfly numbers doubled this winter — and experts don’t know why
In yet another dismal year for California’s dwindling monarch butterfly population, one place stood out as a beacon of hope: Pismo Beach.
Just under a quarter of the state’s monarch butterfly population spent the winter in the Pismo Beach’s grove, according to data from the Xerces Society released Thursday, and the local site hosted more than twice as many butterflies in 2019 as in 2018.
The nonprofit organization conducts an annual count of monarch butterflies wintering throughout the state on Thanksgiving Day in 2019. Data from the study, called the Western Monarch Thanksgiving Count, gives an annual look at the state of monarch butterflies throughout the state.
Volunteers counted 6,735 butterflies in Pismo Beach on Thanksgiving, compared with 3,082 the year before.
“There are really good numbers there,” Xerces Society senior conservation biologist Emma Pelton told The Tribune on Thursday. “It’s something that I know the Pismo managers are going to take a lot of pride in — ‘We’ve got a lot of monarchs.’ ”
When asked why Pismo Beach’s number increased while the rest of the state seemed to dwindle, Peleton responded, ”We don’t know.”
“We don’t know why there,” she said. “But that’s a very sizable chunk of the total population (in California).”
California’s monarch butterfly numbers ‘critically low’
The numbers for California as a whole weren’t quite so rosy.
In total, volunteers counted only 29,418 butterflies across the entirety of California in 2019.
In their heyday, more than 1 million monarch butterflies wintered in the state.
“I’ve been at sites with 25,000 (butterflies) just a few years ago, and now we are excited to just see 2,000,” Peleton said. “It’s a precipitous, shocking drop.”
Though the numbers fluctuated over the years, the population crashed between the 2017 and 2018 seasons, dropping from more than 192,000 to a mere 27,721 butterflies across the state.
Most experts cite a loss of overwintering habitat to drought and human development as a factor in the population’s overall decline.
The spread of development and pesticide use has also endangered milkweed — an incredibly important part of the monarch butterfly life cycle, because it’s the only plant on which the butterflies will lay their eggs, and their only food source as caterpillars.
So where did the butterflies go? Are they flocking somewhere else?
Peleton said it seems that there are just fewer butterflies than there used to be.
“We all wish there were some secret monarch hangout,” she said. “Every year we find new spots — they are dynamic and show up in new places. ... We feel pretty confident that if there were monarchs hanging around in some areas far from the coast we would hear about it, but we just aren’t.”
“Unfortunately, we think they are just missing,” she said.
The monarch butterfly population did grow slightly between 2018 and 2019, according to the new data, but the increase is virtually insignificant, Peleton said.
“We’ve got a lot of work to do,” she said.
What can you do to help?
There are some easy ways to help protect the at-risk species, according to Peleton.
The most popular is planting milkweed inland away from overwintering sites, but Peleton cautioned hopeful gardeners to ensure that they use native milkweed and not the tropical milkweed that is often found in nurseries.
Tropical milkweed tends to be treated with more pesticides, and can severely damage the life cycle of the butterflies, she said.
Another easy solution is just to plant more flowers and plants in general, she added. Those help not only monarchs but also other species of butterflies and insects.
Peleton also cautioned people to reduce their pesticide use and consider shopping from organic farms and food providers that don’t use pesticides or use less of them.
Peleton’s final piece of advice for helping monarch butterflies was to encourage state leaders to protect overwintering sites from development.
“We need you to be advocates and make sure those are protected,” she said.
Solve the monarch mystery challenge
If you don’t have a green thumb, but do have a cellphone, you can help keep track of the population via a new social media campaign called the Western Monarch Mystery Challenge.
The challenge aims to help conservationists figure out where the butterflies go between the wintering season, which ends in February, and breeding season, which starts in May.
To participate, download the iNaturalist app and join the Western Monarch Milkweed Mapper project. If you see a monarch butterfly outside of the overwintering groves between Feb. 14 and April 22, take a picture, add the location and then post it to the app.
This will help track where the heaviest concentrations of butterflies are, and could lead to further insight into why they have declined, Peleton said.
More information on the Western Monarch Mystery Challenge can be found on Facebook at www.facebook.com/pg/monarchmystery.
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