Brisbane fire a mixed blessing

Publisher: San Mateo County Times
Reporter: Julia Scott

Brisbane fire a mixed blessing for endangered butterfly species
Experts say species' rebound depends on plants' regrowth
By Julia Scott
San Mateo County Times
Article Launched: 06/24/2008 07:09:32 PM PDT

BRISBANE - When the flames roared through the southern slope of San Bruno Mountain on Sunday, all Ken McIntire could think of was the Calippe Silverspot butterfly. The butterflies were in the midst of laying their eggs along the ridgetop seared by the fire.

Fire-charred ridges and valleys, black as charcoal or white with ash, were all that remained Tuesday of the habitat for the world's most robust populations of Calippe Silverspot and Mission Blue butterflies. Some parts of the valley were still smoldering from the fire, sending smoke into the atmosphere.

"It's just been burned to a crisp," said McIntire, surveying the damage.

Whether the butterfly populations rebound next year depends entirely on how well the native plants that support the butterflies regrow in the ridges and valleys affected by the fire, according to experts. The plant the Calippe Silverspot lays their eggs on at this time of year - Johnny jump-up - disappeared without a trace in the fire. The hardier lupin plant, which hosts the eggs of the Mission Blue butterfly, is likely to come back sooner.

Fire may have a strongly positive role to play in helping to regenerate healthier soil conditions for the native grasses and plants the butterflies need, but it often is a mixed bag, according to Mike Forbert, a Pacifica-based consultant whose company, West Coast Wildlands Inc., helps San Mateo County control the spread of invasive plant species on San
Bruno Mountain.

"By reducing thatch, the dead grass that builds, it opens up the soil for the perennial grasslands to germinate. But it also opens up the surface area to invasives like the Italian thistle and mustard plant," said Forbert.

It is a source of hope that McIntire clings to. When the grasslands regrow, he hopes a collection of surviving butterflies from a part of the ridge spared by the fire will fly over and colonize the area. A land survey conducted Tuesday by Forbert's team documented six Calippe Silverspot butterflies fluttering over the charred acreage from a neighboring area.

McIntire is also touring parts of the ridge most frequented by the Mission Blue, which lays eggs earlier in the season than the Silverspot. Some of those eggs already may have hatched into caterpillars that could have been hiding in the thatch when the fire swept through - or so he hopes.

"If the fire went by really quickly, they may have been saved," he said.

In some ways, the Brisbane fire makes a good argument for "controlled burns," or scheduled wildland fires that are allowed to burn a specific area under close supervision by fire crews and ecologists. If the shrubbery had not been allowed to grow untamed for so long, it would not have burned so widely, said Dave Holland, San Mateo County's parks director.

Burning is natural, and lightning strikes are a leading cause. But the Ohlone Indians used controlled burns to manage their plant communities more than 5,000 years ago; when the Spanish colonists took over, they accomplished the same thing with cattle grazing.

Intentional burning was a regular county practice on San Bruno Mountain for decades until 2001, when a controlled burn in Brisbane's Wax Myrtle Ravine got out of control and nearly destroyed several homes, according to Holland. Still, his agency has not given up on it.

Instead of burning invasive plants out, the county currently spends about $120,000 a year on pulling weeds out of key areas along San Bruno Mountain. The county could easily spend $400,000 on the job and be more effective, Holland said.

"If we could do a couple hundred acres of controlled burns a year, it would save us a lot of money. It's the most effective way to support a situation where you want more grassland," he said.

Bringing back burns may not be an option in the immediate aftermath of the most recent fire, Holland acknowledged.

"I would like to keep that tool in the toolbox. If the time politically is more amenable to bringing the tool back, I think we should do it," he said.

The cause of Sunday's fire on San Bruno Mountain has not been determined and is still under investigation, according to North County fire authorities.

Reach Julia Scott at 650-348-4340 or

The Callippe Silverspot Butterfly is a member of the Nymphalidae, or brush-footed butterflies. The Callippe Silverspot has a wingspan of approximately 4.5 cm. Members of this species are mainly orange, tan and brown. The name "silverspot" refers to silvery patches of scales on the undersides of the wings. Historically this butterfly inhabited grasslands ranging over much of the northern San Francisco Bay region. On the San Francisco peninsula, this butterfly is now only known to live on San Bruno Mountain.

The Mission Blue Butterfly, Icaricia icarioides missionensis, is a blue or lycaenid butterfly subspecies. The Mission Blue is about the size of a quarter (21-33 mm) with even smaller larvae which are very rarely seen. Its wingspan is around 1-1 inches. The top wing is iridescent blue and lavender. The margins of the upper wing are black and sport "long, white, hair-like scales." The Mission Blue is native to the San Francisco Bay Area and on the San Francisco peninsula is known to live on San Bruno Mountain.