Sunday, October 26, 2008

Ohlone Tiger Beetle, Myrtle's Silverspot Butterfly, and coastal grasslands

There are three rare insects that could be living in coastal San Mateo County in northern California - the endangered Ohlone tiger beetle (Cicindela ohlone), endangered Myrtle's silvespot butterfly (Speyeria zerene myrtleae), and the alledgedly extinct Strohbeen's parnassius butterfly (Parnassius clodius strohbeeni).

The Ohlone tiger beetle is only known from a handful of native grasslands to the south in Santa Cruz County, but the coastal grasslands south of Pacifica to Ano Nuevo State Reserve have not been surveyed for the animal, or Myrtle's silverspot butterfly, for that matter. Myrtle's was last seen in San Mateo County back in the 1950s, but few collectors have looked for it there, most going p to Marin County to get specimens. Stohbeen's parnassius - last seen in 1958 - an another extinct animal that may rise from the dead (like the "extinct" Palos Verdes blue butterfly) - that an intrepid and observant biologist may find in an isolated coastal canyon in San Mateo County. Look for it near bleeding heart (Dicentra formosa), the hostplant of the caterpillar. Butterfly collectors, bird watchers, and others have a habit of going where they know their prey is found; few trailblaze into new areas. In fact, there was a scientific paper published in the 1990s that described how most rare plant records are found within a few miles, if that far, of roads, because some biologists evidently don't walk very far from their cars.

Coastal grasslands are a beautiful and vanishing habitat in California. Richard Minich did a fantastic job of reconstructing the pre-European vegetational communites in the Golden State in his book California's fading wildflowers Los Legacy and Biological Invasions. One of my treasured possessions is the San Franciso Wild in the City, a poster that maps the vegetation of the San Francisco pennisula prior to 1750.

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