Thursday, April 16, 2009

A Visit to San Bruno Mountain

A Visit to San Bruno Mountain

Today, the endangered mission blue butterfly (Icaricia icariodes missionensis) was on the wing and relatively common during a hike on the southeast ridge of San Bruno Mountain. The beautiful metallic blue males and greyish-blue females were flying about or perching on the lupine foodplants. Other animals were enjoying the warm spring day, including ring-necked snakes, California ringlet butterflies (Coenonympha tullia california), painted lady butterflies (Vanessa cardui), anise swallowtail butterflies (Papilio zelicaon), and pipevine swallowtails (Battus philenor). Johnny jump-up (Viola pedunculata) and other beautiful wildflowers were in bloom.

This is a special place located a few miles north of the San Francisco International Airport on the west side of the San Francisco Bay. It's a 3000 acre semi-wilderness located within one of the largest cities on Earth. It is home to the endangered callippe silverspt butterfly (Speyeria callippe callippe) San Bruno elfin butterfly (Incisalia mossii bayensis), San Francisco lessingia (Lessingia germanorum), and the San Francisco garter snake (Thamnophis sirtalis tetrataenia). Last year, a young mountain lion was spotted on the Mountain! Of course, being surrounded by city, there have been numerous proposals to utilize San Bruno Mountain ranging from removing the top 300 feet and using to enlarge San Francisco International Airport to development of homes.

In 1983, a special permit known as a habitat conservation plan was issued by the Department of Interior that in return for allowing urban development of portions of San Bruno Mountain, the majority was set aside forever as habitat for the endangered butterflies and the snake. Yet, a problem that was unforeseen 26 years ago imperils the site and unless it is brought under control will extirpate many of the endangered and native species of plants and animals.

The threat is a constellation of exotic and highly invasive plants including eucalyptus, gorse, French broom, fennel, Oxalis, and many other species. In addition, the grasslands which are inhabited by the mission blue butterfly and the callippe silverspot butterfly are being replaced by coastal scrub. It is not unreasonable to say that unless dramatic measures are undertaken in the near future, the value of San Bruno Mountain to the four listed butterflies and snake, and many other native species will be minimal or non-existent.


Mr. Smiley said...

San Bruno Mountains a great place. Chris Wemmer, Charlie Cushner. Mike Blackford and I spent many days as youths in the 1950's roaming about the place. Spring was always special with all the flowers and bees, many bumblebees with strepsipteran parasites. We always liked finding the Ring-necked Snakes under rocks because as summer approached they would disappear until the following spring.

I'm glad it's preserved and always look fondly on it as I pass it going from the airport after a trip from Australia. Let's hope some local group will attend to the many adventive plants. Even in the "old days" we were worried about the influx of non-native species. A real problem that needs a solution. There must be a group "Friends of the San Bruno Mountains". If not, it's time to start one.
Dave Rentz

Anonymous said...

Despite apparently being universally disliked for just living on the mountain by anyone on the other side of Hillside, the residents of Terrabay contribute monthly to the butterfly habitat conservation and have agressively worked to plant native species on the "cuts" on the mountain made to facilitate the development. We are also spending considerable monies to begin removal of the very invasive fennel that grows all over - sadly no one else seems to be doing anything and the largest eucalyptus growth is on the drive up the mountain through the state park area

-clark- said...

It seems our society believes that progression is production and developing our land. Luckily for our world there are people who fight for the ideal that production is not just about building and money, but the flourishing of our natural areas in the world. I'm curious and pleased about how the government would respond to the disappearance of a butterfly, which would seem insignificant to them in the larger scheme of things.