Saturday, May 29, 2010

Spermophilus beecheyi

Spermophilus beecheyi
Originally uploaded by The Marmot
California Ground Squirrel

I spotted this ground squirrel munching away in a wildflower meadow, surrounded by pink Clarkia and Birds-eye Gilia.

While they are said to avoid thick chaparral and deep woods, it is the most widespread squirrel in California and the only one one to be found around the edges of chaparral. As with many other species of both plants and animals, human disturbances such as road cuts, trails, and housing developments have allowed Spermophilus beecheyi to expand its range.

It forages on more or less open ground and does not climb trees. As one might expect, they live in burrows which can be 5-200 feet long. The young are born in March or April. My field guide says that they remain underground for six weeks. This seems to be born out by the fact that I just started seeing some little ones about two weeks ago. They stick close to the opening, but seem to enjoy games of tag and wrestling.

Most adult ground squirrels estivate in July and August. I can not say that I blame them, when the temps get in to triple digits I tend to get kind of torpid myself.

Monday, May 3, 2010

Black Mustard

Black Mustard 2
Originally uploaded by The Marmot
Black Mustard

Last week, Holly and I began seeing patches of Black Mustard (Brassica nigra) on the far side of Thompson Creek, west of Higginbotham Park, while walking on the paved path. This is another one of those plants that is so commonplace most people assume that is a native. But, it is not.

Popular lore has it that the early Spanish explorers, such as Juan Bautista de Anza, spread the seeds of this plant along the routes that they forged ala Hansel and Gretel. Presumedly, the plant would be in bloom during the return trip and they could easily find their way home. I would like to think that this story is true. But, table mustard is made from black mustard so no doubt many people planted for that purpose

Whatever the reason, it is now common through out California and dominates the hillsides in our area at this time of year. Each Spring finds the hills covered in bright yellow flowers. The bloom begins in April and can extend through July.

Some sources say that black mustard, though widespread, is not considered to be as big a problem as some other invasive species. It prefers disturbed habitats, such as roadsides, and is not as likely to extend in to truly natural areas. However, fire counts as a disturbance and other studies have shown that mustard has totally displaced many of our endemic fire annuals. It has decidedly naturalized and as people further encroach in the sage scrub and chaparral environments it and other broad-leaved herbs are sure to follow.

Mustard and the majority of the native plant species in Southern California have their roots in the Mediterranean Basin. The climates are pretty much the same which allows these plants to adapt, settle in, and then take over when conditions are ripe.

These conditions are decidedly in force along Thompson Creek. The landscape surrounded on all sides by homes, parks, a flood control channel, and the effects of the Grand Prix Fire of 2003 still in evidence it is the very definition of a disturbed environment. Still it is a welcome oasis from the urban surroundings.