It’s a bad year for butterflies
Unusual weather makes life difficult
By Mike Lee
UNION-TRIBUNE STAFF WRITER
May 12, 2006
from The San Diego Union Tribune
Remember the clouds of painted lady butterflies that swarmed across the county last spring, splattering on windshields and amazing beachgoers?
There’s a good reason you haven’t seen such hordes this season: It’s shaping up to be the worst year for California butterflies in nearly four decades, according to a UC Davis butterfly expert.
“There will probably be long-term repercussions, especially for species already in serious decline,” said Art Shapiro, a professor of evolution and ecology at the University of California. His assessment is based on 35 years of monitoring butterflies in the Bay Area, Sierra Nevada and Central Valley.
Photo: EDUARDO CONTRERAS / Union-Tribune
David Marriott, founder and director of the Monarch Program in Encinitas, said cold weather killed more than 100 of his butterflies, making it necessary to replenish his stock.
Unusual weather in recent months has directly affected the butterflies. But butterfly experts suspect that broader forces, including urban development and climate change, also are at work on the dainty creatures.
A cold and wet March hampered breeding in Northern California and spots along the coast, knocking both plants and butterflies off their normal spring schedule by at least a month. In addition, a relatively dry winter in the state’s deserts stunted vegetation growth and thus limited the amount of food available for caterpillars.
Factors influencing butterfly populations are complex, said Lynn Monroe, who runs the Granite Ridge Nature Institute in Lyons, Colo., and leads an annual spring count of the winged insects near Borrego Springs.
“There’s water and there’s temperature and there’s wind” and the timing of rainfall, said Monroe, co-author of “Butterflies & Their Favorite Flowering Plants.”
Photo: EDUARDO CONTRERAS / Union-Tribune
Brandy Hearn (left), 7, and Alisson Barrera, 6, students at Central Elementary School in City Heights, examined a butterfly at the Monarch Program’s butterfly house.
In recent years, other natural phenomena also have played a role in some butterflies’ decline. For instance, wildfires in 2003 wiped out big patches of native habitat in San Diego County and pushed at least two butterfly species closer to extinction.
This year’s dearth of butterflies is particularly noticeable compared to the bumper crop in 2005.
At most of his research sites, Shapiro said he has counted fewer than half of the species that he typically finds. Near Vacaville last month, for example, he spotted 10 species and 43 individual butterflies, compared with 21 species and 378 butterflies in April 2005.
San Diego County, home to about 130 butterfly species, is no exception.
In Anza-Borrego Desert State Park, for instance, tens of thousands of painted ladies overwhelmed Monroe and other visitors last year.
Not so this spring. “We saw two painted ladies all March,” Monroe said.
David Marriott, founder and director of the Monarch Program in Encinitas, agreed that it has been a bad year.
“I have been out in the field quite a bit . . . and there is just nothing. I can’t believe it,” said Marriott, who rears several species of butterflies to sell to researchers and the public.
At his butterfly house, a popular destination for school groups, Marriott said it took unusually long for monarchs to emerge from their chrysalises this spring. When they finally came out, it was too cold for them to fly about and mate. More than 100 died, forcing Marriott to replenish his stock from a colleague in Carpinteria.
“I had nothing for the first time ever,” Marriott said. “I have got to have butterflies for the kids.”
Marriott doesn’t worry much about a short-term downturn, especially since a string of warm days should help some butterflies rebound within weeks.
“They are insects and they fluctuate like stock market graphs,” he said. “They will bounce back. They always do.”
But Marriott and others are concerned about how climate changes are affecting butterfly populations. Shapiro suspects global warming is to blame for long-term declines in some types of California butterflies.
“We are seeing similar phenomena in other (species) and in other parts of the world, all of which seem to be components in a larger picture,” he said. “We just haven’t got a big enough HDTV screen to see it in its entirety – yet.”
Others worry about urban development wiping out native butterfly habitats, particularly in Southern California.
“Food plants are being knocked down by . . . weed wackers,” said Trish Meyer, president of the North American Butterfly Association chapter in Los Angeles.
She suggests that homeowners grow native, butterfly-friendly plants in their yards; others say it’s helpful to support conservation groups that protect undeveloped lands.