Beating Back Extinction One Plant at a Time
April 16, 2014
Peaking out from an unassuming hillside along a well-traveled road north of the Bay Area is one of California's most endangered plants, Baker's larkspur. From theft to fire, to flooding, the plant known to botanists as Delphinium bakeri has been through the ringer.
Luckily for this lonely flower botanists from the University of California Botanical Garden at Berkeley have been working closely with biologists from the U.S. Fish & Wildlife Service's Sacramento Field Office to improve species chances of survival.
Baker's larkspur is a perennial herb in the buttercup family that grows from a thickened, tuber-like fleshy cluster of roots. The stems are hollow, erect, and grow to 26 inches tall and flowers from April into May. The plants require pollination by bumblebees or hummingbirds.
Where does one go to find the plant worthy of a Shakespearean-type tragedy? In order to protect the remaining plants the Service doesn’t give out specific locations but we can say that the only remaining naturally occurring population of Baker’s larkspur is located on a steep embankment along Marshall-Petaluma Road in West Marin. Not long ago, this was the only place on the planet that these plants were found.
It's been 10 years since fire nearly eliminated Baker's larkspur
from its one remaining location alongside a busy road in West
Marin but the plant is still hanging on.
Photo Credit: Kate Symonds/USFWS
A beautiful flowering plant, Bakers larkspur is a perennial herb in the buttercup family that has faced an almost unbelievable series of unfortunate events in its bid to avoid extinction. Here’s a quick look back at the steps that lead this plant to life on the edge:
- Considered rare when it was formally described in the late 1930's, Baker’s larkspur has only ever been found in three locations, one in Sonoma County and two in Marin County.
- In 1992, all the capsules were collected by unknown individuals, which resulted in all sexual reproduction for that year being lost.
- Originally proposed for listing in 1976, by the time the species was listed on January 26, 2000, two of those three locations had been lost to the plant, leaving the steep roadside embankment the plants only home.
- By 2001, the one remaining site had only 55 flowering plants.
- In 2002, despite repeated discussions between the Garden staff and others with the agency responsible for roadside maintenance, local work crews gouged the slope removing the largest plants before seed set was completed.
- In September 2004, fire-fighting crews set backfires on the slope above the Delphinium bakeri, in efforts to control a wildfire that started nearby. The only individuals that survived were those that were protected by the roots of woody plants or were growing low on the slope and escaped being burned.
- One month later, in October 2004, during maintenance local road crews removed most of the remaining individuals from the slope while clearing out the culvert located below the population, although the slope above the culvert had not eroded to block the culvert.
- By 2007, only seven plants appeared, only two of those flowered but both of those plants lost their flowers before seeds set.
One of the many challenges facing Baker’s larkspur is its basic biological need to grow on a shaded, but not too shaded, hillside where it can drop seeds below it. As the plants cycle through the generations, soon the seeds drop into the ditch and are washed away.
Baker's larkspur's story doesn't end there. Because the plant is so rare, little is known about what specifically the plant needs to pull it back from the brink. Staff of the Garden and Service biologists put their heads together to carefully select new planting sites, based upon what is known of the species' habitat requirements, required habitat conditions for similar species, and the availability of willing and interested owners of lands whose use could be compatible with Bakers larkspur recovery efforts.
Because there are so few plants in a very limited amount of space at only 4 sites, the number of threats facing the species is large. One hungry banana slug could eat half of a population in short order.
Determined to give the plant a real shot at survival, in 2009, Garden staff, led by Holly Forbes and under contract with SFWO, introduced plants propagated from wild seed to three sites within its historic range: two on private ranches, and the third site on Marin Municipal Water District's land near Soulajoule Reservoir. All are within three miles of the last remaining occurrence in Marin County.
One of the ways to ensure the Baker's larkspur has a better chance at survival is to plant it at other natural sites that closely match the one remaining natural location. One such location was on a private, working vineyard where conservation minded owners were excited to make a space for the plant. Although the plant has had some success in its new location there, it has been limited and the species continues to struggle.
Between 2009 and 2011, over 200 plants raised in the nursery by the Garden were planted in those experimental locations. Although the sites all had some success, the challenges facing the species weren’t left by the side of the road. Many of the plants were eaten by banana slugs or other animals. Some reached maturity but didn’t flower. Even those that did flower often lost their flowering stem before setting seeds. Adding insult to injury, trees fell at two of the three sites changing the microclimate of the locations.
Nature may be beautiful but it is seldom kind.
Still Garden and SFWO staff members have persevered. Despite falling trees and crashing budgets, a small but dedicated crew keeps the species from extinction.
Seen as a short-term strategy, these plants have been raised
at the Garden’s nursery. Only seed collected in the wild is
grown and then plants are transferred to the wild. Raising
and collecting seed from plants in the nursery is not a good
long-term strategy because it inadvertently selects for plants
that thrive in an artificial setting, and may over time
compromise the gene pool when mixed with wild-selected seeds
or out-planted directly. Photo Credit: Valary Bloom/USFWS
Working without federal funding since 2013, Garden staff and volunteers continue to monitor the original and experimental sites. Counting starts in early spring just as the first leaves burst bright green from the soil. Periodically, new plants are propagated in the nursery and are out-planted when new information about habitat requirements is learned or additional opportunities for landowner partnerships arise.
In the meantime, a draft recovery plan for the species is in development. It describes what is known in regards to the species needs and lays out the recovery strategy, with detailed steps and estimated costs for immediate action. Release of this important document and invitation for public comment is expected by the end of 2014.
Recovery is the ultimate goal of the Endangered Species Act. Sometimes success needs to be measured one plant at a time.
by Sarah Swenty / SFWO External Affairs