Category Archives: nature

Dealing With Drought

Goldfields (Lasthenia spp.) on Lasky Mesa in Upper Las Virgenes Canyon Open Space Preserve.

This photograph of goldfields (Lasthenia spp.) was taken on a run on Lasky Mesa in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch) almost exactly one year ago.

This April I haven’t seen any goldfields on Lasky Mesa. The soil is too dry for the seeds to germinate. The drought in Southern California has suppressed or delayed the growth of these, and many other species of wildflowers. This is one of the ways that annuals deal with drought — if the growing conditions aren’t appropriate, they don’t grow.

Black mustard, an invasive annual from Europe, is a hardy plant that is a good indicator of Winter rainfall. In 2005 and 2006 the mustard at Ahmanson Ranch was 6′ to 8′ tall and very widespread. This year its growth has been very limited, and the plants are diminutive in comparison.

Plants deal with drought in many other ways, such as dropping leaves, changing the leaf distribution, reducing the size of the leaf, changing the leaf orientation, modifying the shape of the leaf, or changing the leaf color. Flowering may be suppressed, or the flowering time shortened. In some cases the flower may be reduced, or viable fruit may not be produced. Branchlets or stems may be lost. Any life prolonging tactic may be employed when survival is at stake.

According to the NWS, if Los Angeles (USC) receives less than 1.95 inches of rain between now and June 30th, this water year (July 1, 2006 to June 30, 2007) will become the driest since recordkeeping began in 1877. At this point in the season, a new record seems more likely than not.

It was only 5 years ago (2001-2002) that Los Angeles experienced its driest water year so far, recording only 4.42 inches.

Related post: A Little Rain in Los Angeles

Bush Monkeyflower

Bush monkeyflower (Mimulus aurantiacus) readily hybridizes, producing a myriad of forms and colors.

Bush monkeyflower (Mimulus aurantiacus) readily hybridizes, producing a myriad of forms and colors, and some interesting work for botanists. This plant pictured above may be a hybrid of local salmon and scarlet colored forms.

Update June 10, 2011. The Diplacus section of Mimulus has been the source of much taxonomic turmoil, with the number of species varying from two to 13. Research by Tulig & Clarke found that most named taxa in this group can be distinguished based on morphological characteristics. Accordingly, the monkeyflower pictured above would correspond to a variety of Diplacus longiflorus (Southern bush monkeyflower).

The scarlet variety is sometimes referred to as Diplacus rutilus (Santa Susana bush monkeyflower).

From a run near Sage Ranch on March 26, 2007.

Eastwood Manzanita

Ants forage among the blossoms of Eastwood manzanita on the Chumash Trail in Rocky Peak Park.

Ants forage among the blossoms of Eastwood manzanita on the Chumash Trail in Rocky Peak Park. From a run on Wednesday, March 21, 2007.

Some related posts: Chumash-Las Llajas Loop, Chumash-Hummingbird Loop, San Fernando Valley from Rocky Peak, Chumash Trail Snow.

A Little Rain in Los Angeles

Droplets of rain on the funnel shaped web of the western grass spider, Agelenopsis aperta.

We received a little rain in the Los Angeles area earlier this week. There was just enough light rain to dampen my shirt, muddy my running shoes, and ornament this web with droplets of water. Refreshing as it was, the precipitation did little to relieve our ongoing drought.

To date, according to NWS data,  this is the driest water year in Los Angeles since recordkeeping began in 1877. From July 1, 2006 to March 22, 2007 Downtown Los Angeles (USC) has recorded only 2.47 inches of rain. This is 10.79 inches below normal. Checking back through NWS records, 2.47 inches is the total amount of rain recorded in Downtown Los Angeles from May 23, 2006 through today — a period of 10 months!

In the past few years Los Angeles has experienced a number of weather extremes. The driest water year on record for Los Angeles was just set in 2001-2002, when 4.42 inches were recorded. Then in 2004-2005, Los Angeles was deluged with 37.25 inches of rain — the second wettest on record. During that period, Opids Camp in the San Gabriel Mountains recorded over 100 inches of precipitation! In July of last year Pierce College in Woodland Hills recorded a new all time high temperature for that station of 119°F. This may have been the highest temperature ever recorded in Los Angeles County. In mid January of this year many new record low temperatures for the date were set in the Southern California area. Pierce College plunged to a record low of 20°F (-6.7°C) and a temperature of 10.4°F (-12°C) was recorded at a research site in the Santa Monica Mountains. 

Computer models are indicating another chance of rain early next week. At the moment, the system looks like it could produce rainfall amounts similar to Tuesday’s system, perhaps a little more. But with the equatorial Pacific and atmosphere looking more and more La Nina like, significant rain is looking less likely, and we may be talking about record drought in Southern California for many months to come.  We’ll see!

The photo of the wet spider web was taken near Lasky Mesa in Upper Las Virgenes Canyon Open Space Preserve (formerly Ahmanson Ranch) on Tuesday, March 20, 2007. The funnel shaped web is probably that of the western grass spider, Agelenopsis aperta.

Related posts: Chaparral Freeze, The Color of Rain, El Nino Drought, Sunset Snow Shower, Rainy Morning on Rocky Peak Road.

Laurel Sumac

New growth on the chaparral shrub laurel sumac (Malosma laurina) at Sage Ranch Park.

New growth on the chaparral shrub laurel sumac (Malosma laurina) at Sage Ranch Park. The red pigment may function as a sunscreen, protecting sensitive new leaves until they mature, and can cope with full sun.

In mid January there was widespread freeze damage to laurel sumac in the Santa Monica Mountains, and other wildland areas near Los Angeles. Although the plant pictured above was not damaged, many laurel sumac plants in low lying and wind protected areas were.

But frost, fire or drought, laurel sumac is a resilient plant that can weather most hazards. At Sage Ranch, many of the plants damaged in the January freeze have already sprouted new growth.

From a run at Sage Ranch on Monday, March 12, 2007.

Related posts: Chaparral Freeze, Poison Oak.

California Prickly Phlox

California prickly phlox (Leptodactylon californicum) likes warm, rocky, southwest facing slopes.

A Winter bloomer, California prickly phlox (Leptodactylon californicum) likes warm, rocky, southwest facing slopes where it can bask in the afternoon sun. The flowers have a subtle, musty-sweet fragrance that is especially pleasant when encountered on a still evening, in fading twilight, near the end of a run.