Brief Overview
A perennial herb of shaded Marin and Sonoma Ccounty woodlands, Baker’s larkspur
(Delphinium bakeri) is known from only one small historical occurrence along Marshall-
Petaluma Road in Wwest Marin Ccounty, California.
Description and Taxonomy
Baker’s larkspur is a perennial summer-dormant herb in the buttercup family (Ranunculaceae)
Baker's larkspur is a striking plant that grows up to 65 centimeters (26 inches) tall, characterized by its thick, tuber-like roots The leaves, primarily located in the upper third of the stem, are five-parted and green during flowering, featuring a distinctive whitish area at their center The irregularly shaped flowers showcase five prominent sepals that are bright dark blue or purplish, with the rear sepal extending into a spur The inconspicuous petals come in two pairs, with the lower pair being blue-purple and the upper pair white This species produces several dry, many-seeded fruits called follicles that split open on one side when mature Unique features of Baker's larkspur include notched or scalloped leaf margins, leaves that remain intact during flowering, and loosely arranged flowers, all of which help distinguish it from other members of its genus.
Baker’s larkspur is acknowledged as a legitimate species in various authoritative floras, including The Flora of North America North of Mexico (1993), An Illustrated Flora of the Pacific Northwest (1944), A California Flora (1959), Marin Flora (1970), The Jepson Manual (1993), and A Flora of Sonoma County (1996).
Distribution and Habitat Use
Baker’s larkspur occurs on decomposed shale at an elevation range of 295 (90 m) to 672 feet
Baker’s larkspur, a plant species endemic to Marin and Sonoma counties, has historically been found in only three locations: one in Sonoma County and two in Marin County By the time it was listed in 2000, its original habitat in Coleman Valley, west of Occidental in Sonoma County, had been transformed into a dairy ranch Ewan (1942) documented details about this site, highlighting the limited distribution of this species.
Coleman Valley in Sonoma County is the original type locality where the species was first described, specifically found "along fence rows and in heavy low brush." At this location, Baker’s larkspur coexists with two other species, including Horkelia californica ssp dissita, commonly known as California honeydew.
Ranunculus orthorynchus (straightbeak buttercup) The second known site, in Tomales, Marin
The Tomales occurrence, documented in a 1923 herbarium collection, was believed to be extirpated by the time of its listing, with no habitat information available (CNDDB Occurrence 3, CNDDB 2008) The third locality is situated along a steep roadside embankment next to Marshall-Petaluma Road within the Marin County right-of-way.
The only known historical occurrence of Baker's larkspur is documented at CNDDB Occurrence 1, alongside three additional sites where the species has been recently reintroduced The last historical population is located along Marshall-Petaluma Road, thriving in moderately moist, shaded conditions on a shallow layer of soil on a north-facing slope Key plant associates for this species are detailed under Critical Habitat.
The Marshall-Petaluma Road site, which experienced a fire in 2004, has undergone significant changes in vegetation and microsite conditions The loss of the California bay laurel canopy has resulted in increased sunlight, leading to the proliferation of invasive species such as poison hemlock, wild oats, and French broom, which were previously less common Native California blackberry has become denser, posing a potential threat to Baker’s larkspur Consequently, the site has shifted from a moist and shady environment to a drier and sunnier one.
Since March 2009, the UC Botanical Garden at Berkeley (UCBG) has been working under a contract with the Service to introduce Baker’s larkspur to three sites within its historic range These sites include two private ranches and three separate plantings on Marin Municipal Water District land near Soulajule Reservoir, all located within three miles of the last remaining occurrence in Marin County The status of these introductions is further detailed under Abundance and Trends.
Critical Habitat
The critical habitat for Baker’s larkspur, as observed on the Marshall-Petaluma Road site, is primarily characterized by soils derived from decomposed shale and a variety of plant communities that support associated species Key plant species in this habitat include California bay laurel (Umbellularia californica), California buckeye (Aesculus californica), coast live oak (Quercus agrifolia), coyotebrush (Baccharis pilularis ssp consanguinea), snowberry (Symphorcarpos cf rivularis), and wild blackberry (Rubus ursinus).
(California blackberry), Pteridium aqulinum (bracken fern), Polystichum munitum (sword fern),
Pityrogramma triangularis (goldback fern), Dryopteris arguta (coastal woodfern), Adiantum jordanii (maidenhair fern), Polypodium glycyrrhiza (licorice fern), Toxicodendron diversilobum
(poison oak), Ceanothus thyrsiflorus (blueblossom ceanothus), Lithophragma affine (woodland star), and Holodiscus discolor (oceanspray); and (3) mesic (moderate moisture) conditions on extensive north-facing slopes (Service 2003).
Life History
Baker’s larkspur blooms from April to May and is primarily pollinated by bumblebees and hummingbirds While this plant is self-compatible, it relies on pollinator visits to achieve optimal seed production and quality.
Po in t R ey es N atio na l S ea sh ore
Figure 1 Historical and Current Distribution of Baker’s larksp ur
Abundance and Trends
Since spring 2001, the UCBG Garden staff has consistently monitored the last remaining historical population of Baker’s larkspur along Marshall-Petaluma Road, which initially included 55 flowering individuals Over the years, this population has fluctuated between 60 and other varying numbers.
From 2001 to 2003, a total of 100 individual plants were recorded; however, their numbers declined significantly due to severe damage from road maintenance crews in 2002 and 2004, as well as a wildfire in 2004 By spring 2005, only nine plants were observed, with just two flowering and only one producing seeds In spring 2006, seven plants were noted, but of the two that flowered, one stem had all flowers abort, while the other was broken before full bloom.
Numbers increased slightly the following year; however, flowering individuals since 2007 have consistently numbered between only two and four plants (Forbes, pers comm 2008) In
In summary, abundance at the historical population has been extremely low, but fairly stable over recent years (Table 1).
2012 11 4 Low seed production (not quantified; no seeds collected)
2013 XXX XXX data provided by Holly Forbes, UCBG
Table 1 Survey data for the last remaining historical population of Baker’s larkspur.
In 2006, the UCBG Garden initiated propagation efforts to mitigate the extinction risk of Baker’s larkspur and to supply propagules for reintroduction into its historical range Since the reintroductions commenced in 2009, the abundance of Baker’s larkspur at the three designated sites has fluctuated.
In March 2009, eleven plants were out-planted at a private ranch off Marshall-Petaluma Road as part of a pilot project Unfortunately, a large oak tree fell in early 2011, covering the site with sawdust and hindering seed germination and growth from 2010 By spring 2011, five plants emerged, with three flowering; however, their fruiting stems were likely destroyed by gopher activity, preventing seed maturation In 2012, only one plant survived, prompting the outplanting of seven additional plants in February Although seed production was not measured, all plants subsequently flowered and set seed To protect the plants from slug predation, copper sheet metal fencing was installed around all but one plant in 2012.
In 2013 plants emerged Of these, flowered and of those, produced seeds Also, in
In 2013, it was noted that copper sheet metal fencing led to the buildup of plant debris, which posed a risk of suffocating new seedlings As a result, the decision was made to cease the use of this fencing method.
Chileno Valley Road: 75 plants total out-planted at three sites on this private ranch between
Between December 2009 and January 2011, a total of 25 plants were out-planted across three sites By March 2011, herbivory from banana slugs significantly impacted plant survival, leaving only five plants at Site 1 and nine at Site 2 with above-ground growth In Site 1, no flowers or seeds were produced in 2011, while Site 2 likely had three flowering plants In 2012, Site 1 observed one seedling, while Site 2 had three plants that flowered and set seeds Site 3 initially showed resilience, with 21 of 25 plants surviving as of March 2011, and ten expected to flower Although only one plant flowered in 2012, it resulted in 185 seedlings due to a strong seed set in 2011 Further observations in 2013 across all sites recorded emerging plants, flowering instances, and seed production.
Soulajule Reservoir: 110 plants total were out-planted at three sites on public land between
In January 2010, forty plants were out-planted at Site 1, with 26 remaining by March 2011 and 730 seedlings observed By May 2011, one plant produced four capsules, but in 2012, only two one-year-old plants emerged, neither of which flowered, although 56 seedlings were noted In 2013, additional plants emerged, with some flowering and producing seeds At Site 2, thirty-five plants were out-planted in January 2011, with observations continuing in March 2011 Unfortunately, none of the plants from either site produced flowers or seeds in 2012.
By May 2011, only 33 plants remained, with nine of the original 35 producing a total of 77 capsules The initial planting year saw no seedlings, but in 2012, while no plants flowered, 62 seedlings were observed.
2013 plants emerged Of these, flowered and of those, produced seeds Site 3: Thirty-five plants were out-planted in January 2011 As of March 2011,
34 plants remained and by May, 14 out of the 35 plants had capsules, totaling 151 capsules No seedlings were observed because it was the initial planting year In
2012, no plants flowered, but 27 seedlings were observed In 2013 plants emerged Of these, flowered and of those, produced seeds seeds
Among the three reintroduction sites, the area surrounding Soulajule Reservoir, managed by Marin Municipal Water District, showed the most potential for long-term establishment up until 2012 However, population numbers are occasionally constrained by predation from invertebrates and mammals, as detailed in the discussion of Factor C threats.
Threats
Factor E
Baker’s larkspur faces a critical threat from the extirpation of its small populations, which have already suffered from diminished genetic diversity and restricted habitats due to random events Furthermore, global climate change poses an additional risk to the species across its entire range.
Baker's larkspur faces a high risk of extinction due to its small population size, limited range, and susceptibility to human disturbances Factors such as changes in the local micro-climate and herbivory at reintroduction sites further threaten its survival The future of this species hinges on the effectiveness of both past and upcoming reintroduction efforts.
Conservation and Recovery Efforts to Date
Goal
The primary aim of recovery planning is to enhance a species' status so it no longer needs protection under the Endangered Species Act Currently, we cannot establish delisting criteria for Baker’s larkspur due to insufficient information on its biology and habitat needs, its limited range, significant threats, and the unstable environment it inhabits Consequently, this recovery plan focuses on improving the status of Baker’s larkspur to potentially allow for its downlisting from endangered to threatened status.
Objectives
To achieve this goal, the following objectives have been developed:
1 Secure 12 self-sustaining populations of Baker’s larkspur throughout its full ecological, geographical, and genetic range.
2 Ameliorate or eliminate the threats, to the extent possible, that caused the species to be listed and any future threats.
Recovery Criteria
Recovery Strategies
The recovery strategy for Delphimium bakeri has five basic components They are monitoring, reintroduction, management, research, and outreach Here we discuss each component in detail.
Monitoring the reintroduction and historical sites is essential for assessing population status and trends This data is crucial for making informed management decisions and evaluating progress towards recovery criteria and objectives.
Annual surveys of all populations are essential to evaluate basic population status, including the overall condition, number of mature plants, and presence of seedlings However, implementing a more comprehensive monitoring program is ideal as it provides a clearer picture of the population's health Key aspects to consider for an effective monitoring plan should be tailored based on available resources, such as staff or volunteer time, and the frequency of site access.
To effectively assess the population of Baker’s larkspur, it is essential to conduct repeated site visits, particularly during the flowering period to evaluate reproductive output comprehensively Key parameters to consider include the number of individuals at each life stage (seedling, juvenile, adult), leaf area index, levels of herbivory or disease, the number of flowering adults, flowering timing, flowers per inflorescence, spikes per plant, seeds produced per flower or plant, individuals producing fruit, seed viability (germination rate), and the survival rate of individual plants across years.
Habitat assessment data is crucial for an effective monitoring program and should encompass the composition and health of the plant community at the reintroduction site, including the presence of invasive species and identification of pollinators Key factors to evaluate include soil moisture levels, seasonal variations, and overall site condition By collecting a sufficient sample size, statistical analyses can be employed to examine the relationships between plant responses—such as establishment, survival, and reproduction—and various environmental factors like soil moisture effects on seedling survival, surrounding plant community composition, pollinator presence, land use, precipitation patterns, and management practices.
Information gathered from monitoring efforts and the evaluation of the data should then be used to refine the selection of other micro-sites for future reintroduction efforts
Threat assessment plays a crucial role in managing Baker’s larkspur populations, focusing on various factors such as invasive species encroachment, herbivory, trampling, erosion, changes in site hydrology, and human disturbances Yearly comparisons of these threats are vital for understanding trends and impacts The data gathered from these assessments will guide the development of effective management strategies for the conservation of Baker’s larkspur.
Photomonitoring is an effective method for documenting vegetation patterns, structures, and temporal changes at specific sites It complements quantitative data collection and offers essential site insights when extensive data gathering is impractical Establishing fixed-point, fixed-perspective photomonitoring at each reintroduction site is crucial for accurate monitoring and assessment.
Monitoring reports are essential for evaluating the status of populations and enhancing the success of future reintroductions, ultimately aiding in the recovery of the species These reports should detail current habitat conditions, vegetation, the number of mature plants and seedlings, observed mortality, conducted activities like weed pulling and fence repairs, and recommendations for site improvement They must assess population stability or growth and confirm the occurrence of a complete life cycle, from seed to viable seed release Additionally, reports should include labeled photomonitoring results, a description of monitoring methods, and the qualifications of data collectors Regular submission of these reports to the Service is crucial, along with prompt notification of any urgent site stewardship issues that may impact the restoration of Baker’s larkspur, such as wildfires.
Due to low population numbers and susceptibility to human disturbances, the long-term survival of Baker’s larkspur at its historical site is improbable To enhance the species' status, reintroductions are crucial, as establishing new, self-sustaining populations in less disturbed, remote areas is essential to prevent imminent extinction.
The UCBG Garden and Service should persist in their efforts to establish additional reintroduction sites within the historic range of suitable habitats The exact number of sites required for long-term success remains uncertain and will largely depend on the willingness of landowners to participate, the availability of Baker’s larkspur for planting, and the necessary labor for stewardship activities Additionally, securing funding and resources, including volunteers, will be essential to support these initiatives for sustainable growth.
To ensure the sustainability of Baker’s larkspur populations and maintain genetic diversity, it is essential to reintroduce a sufficient number of individuals at designated sites Currently, there is a lack of data on gene flow and the minimum viable population size needed for self-sustainability, which is critical given the species' historical population decline and the limited genetic pool from which current plants are propagated With all existing plants derived from fewer than 40 individuals at a single site, the risk of inbreeding depression and reduced genetic diversity is heightened Therefore, securing reintroduction sites is vital for allowing natural selection to take place, as greenhouse-raised generations may inadvertently favor genotypes that thrive in cultivation rather than in their natural habitat.
In the absence of genetic information on Baker’s larkspur, using an initial founder population size at each site of around 30 to 40 satisfies the default recommendation of genetic sampling of
10 to 50 individuals per source population (Guerrant 1996) Founder populations of fewer than
An isolated population of just 20 plants may face increased risks of inbreeding depression and a decline in genetic diversity, which is crucial for natural selection Although the immediate goal of reintroduction is not the long-term growth and survival of the founder plants, their survival is vital until a self-sustaining population with spontaneous seedling recruitment is established To accurately measure population growth, it is essential to focus on mature, flowering, and seed-bearing individuals, as seedlings experience significantly higher mortality rates.
Reintroductions should be conducted in accordance with the guidelines that follow:
The Marshall-Petaluma Road site serves as the sole reference for Baker’s larkspur habitat, as the other two locations have been lost Identifying candidate sites requires analyzing existing literature on historical habitat characteristics, conducting direct observations, and examining the Marshall-Petaluma Road site before and after grading and fire events It is essential to engage landowners within the species' historic range who possess sites with similar slope, aspect, vegetation, hydrology, soil characteristics, and moisture conditions Additionally, the extent and composition of vegetation cover will be crucial indicators for assessing the suitability of transplant microsites.
Each candidate site requires an evaluation of its management needs, such as controlling invasive plants, protecting against herbivory, and providing watering during drought conditions Following this assessment, a detailed budget should be developed, outlining the essential materials and labor for the reintroduction process, along with the necessary personnel involved.
To ensure the successful long-term management of candidate reintroduction sites for Baker’s larkspur, several key characteristics must be met: a cooperative landowner willing to support compatible land uses, minimal invasive vegetation nearby, suitable soil types like decomposed shale, and no signs of erosion that could threaten soil stability Additionally, the site should be free from road or trail right-of-ways to minimize human and vehicle traffic, with access granted solely for management and monitoring activities It should also allow for necessary modifications to management practices to enhance the plant's viability, such as vegetation management and erosion control Furthermore, any access methods and potential site expansions must receive landowner approval, and there should be flexibility to adjust reintroduction boundaries if Baker’s larkspur establishes outside the designated area.
When evaluating potential reintroduction sites, it's crucial to thoroughly assess their growing conditions However, some sites may not succeed for reasons that are not yet understood Consequently, the number of sites selected for reintroduction should surpass the minimum needed to meet downlisting criteria.
Stepdown Narrative
1 Monitoring of all known populations
1.1 Conduct demographic monitoring of the historical population of Baker’s larkspur at Marshall-Petaluma Road and three current reintroduced populations throughout the year to evaluate germination, flowering, and seed set (Priority 1).
1.2 Conduct Action 1.1 for any newly reintroduced populations (Priority 1).
1.3 Monitor threats at the historical population at Marshall-Petaluma Road and three extant reintroduced populations (Priority 1).
1.4 Monitor threats at any newly reintroduced populations (Priority 1).
1.5 Search for new populations within historic range (Priority 2).
2.1 Identify potential additional reintroduction sites (Priority 1).
2.2 Install plants to new reintroduction sites (Priority 1).
2.3 Supplement reintroduced populations with additional individuals (Priority 2).
2.4 Evaluate success of each new reintroduction site (Priority 2).
3 Management of habitat at all populations.
3.1 Adaptively manage threats (herbivory, trampling, competition with other vegetation, soil moisture, hybridization, and wildfire).
3.1.1 Control vegetation at historical and reintroduction sites, as necessary (Priority 2).
3.1.2 Implement measures to control herbivory at historical and reintroduction site, as necessary (Priority 1).
3.1.3 Conduct other management measures, as necessary (Priority 2).
3.2 Conduct amplification of wild-collected seed
3.2.1 (space)Collect seeds in the wild during years of sufficient seed production
3.2.2 For use in short-term reintroduction efforts, propagate to transplant size plants grown from no later than the first generation of nursery-selected see d (Priority 1).
3.2.3 Send a portion of wild-collected seed to a certified seed banking facility (Priority 2).
3.3 Conduct amplification of nursery-collected seed
3.3.1 Collect and process seed from nursery-raised plants (Priority 2).
3.3.2 Store a portion of collected seed from nursery-raised plants onsite and send a portion to a certified seed banking facility (Priority 3).
3.4 Assess effectiveness of management and alter management, if necessary (Priority 2).
4.1.1 Conduct research to determine genetic variability of Baker’s larkspur (Priority 2).
4.1.2 Use results of Action 4.3.1 in studies to determine minimum viable population size for Baker’s larkspur and develop at genetics management plan (Priority 1).
4.1.3 Conduct research to determine whether hybridization occurs between Baker’s larkspur and other common co-occurring Delphinium species (Priority 3).
4.2 Conduct experimental plantings to determine if outplanting of Baker’s larkspur with associated woody species increases transplant survival and whether co-planting other compatible native species increases the presence of appropriate pollinators and results in increased seed set (Priority 3).
4.3 Periodically during the implementation of recovery actions above, determine whether sufficient information exists to describe conditions necessary for the delisting of Baker’s larkspur and develop delisting criteria accordingly (Priority 3).
5.1 Conduct annual education of Marin Ccounty road crews and fire crews working near the historical population site, in regards to protection of Baker’s larkspur populations
Implementation Schedule
The implementation schedule for the draft recovery plan details essential actions and their estimated costs, serving as a roadmap to achieve the objectives outlined in Chapter II It prioritizes these actions, provides a timeline for their execution, identifies responsible parties, and estimates the associated costs Successfully completing these actions is crucial for advancing the recovery of Baker’s larkspur.
Priority 1- an action that must be taken to prevent extinction or to prevent a species from declining irreversibly in the foreseeable future.
Priority 2- an action that must be taken to prevent a significant decline in the species population/habitat quality or some other significant negative impact short of extinction.
Priority 3- all other actions necessary to meet recovery objectives.
As circumstances evolve, it is essential to view priority numbers through the lens of historical and potential future actions at various sites Consequently, these assigned priority numbers serve as a guide for the allocation of limited conservation resources rather than a strict limitation.
Continual- An action that will be implemented on a routine basis once begun.
Ongoing- An action that is currently being implemented and will continue until action is no longer necessary.
Not begun- An action that has not yet begun.
CNPS- California Native Plant Society
MMWD- Marin Municipal Water District
OWN- Agency or Organization that administers or owns each site
UCBG- University of California, Botanical Garden, Berkeley
USFWS- U.S Fish and Wildlife Service
IMPLEMENTATION SCHEDULE FOR BAKER’S LARKSPUR
1 1.1 Conduct demographic monitoring of the historical population at Marshall- Petaluma Road and three current reintroduced populations throughout the year to evaluate germination, flowering, and seed set
Based on (3 days/yr x 4 people for Chileno Vly Rd) +
(3 days/yr x 4 people for total remaining sites) + (3 office days/yr) All at
1 1.2 Conduct Action 1.1 for any newly reintroduced populations
Based on 12 new reintro sites (4 more than required for downlisting) 18 days/yr x 4 people +
(9 office days/yr) All at $400/day.
1 1.3 Monitor threats at historical population at Marshall- Petaluma Road and three current reintroduced populations
0 0 This action directly associated with Actions 1.1 and 1.2
1 1.4 Monitor threats at any newly reintroduced populations
0 0 This action directly associated with Actions 1.1 and 1.2
2 1.5 Search for new populations within historic range
1 2.1 Identify potential additional reintroduction sites
1 2.2 Install plants at new reintroduction sites Ongoing UCBG,
N/A 14.4 Based on 12 new reintro sites (4 more than required for downlisting) 3 people x 1 day/site x
2 2.3 Supplement reintroduced populations with additional individuals.
2 2.4 Monitor success of each new reintroduction site
0 0 This action directly associated with Actions 1.1 and 1.2
2 3.1.1 Control vegetation at historical and reintroduction sites, as necessary
0 0 This action directly associated with Actions 1.1 and 1.2
1 3.1.2 Implement measures to control herbivory at historical and reintroduction site, as necessary
2 3.1.3 Conduct other management measures, as necessary
1 3.2.1 Collect seeds in the wild during years of sufficient seed production
(if collected in 10 of 20 yrs)
Only in yrs when enough natural seed set to collect 1 day/yr x 2 people x
1 3.2.2 For use in short-term reintroduction efforts, propagate to transplant size plants grown from no later than the first generation of nursery-selected seed
Based on 40 plants/yr & 15 day/yr x $400/day x
2 3.2.3 Send a portion of wild- collected seed to a certified seed banking facility
(if sent in 10 of 20 yrs)
Only in yrs when enough natural seed set to collect 1 day/yr x $400/day x
2 3.3.1 Collect and process seed from nursery-raised plants
3 3.3.2 Store a portion of collected seed from nursery-raised plants onsite and send a portion to a certified seed banking facility
Ranch Santa Ana Seed Bank, charges flat fee of $3K.
2 3.4 Assess effectiveness of management and alter management, if necessary
TBD TBD This action directly associated with Actions 1.3 and 2.4
No additional costs Altered management would incur costs to be determined.
2 4.1.1 Conduct research to determine genetic variability of Baker’s larkspur.
Ongoing PVT N/A 80 Lump sum estimate for average genetic study= $80,000
Utilize the findings from Action 4.1.1 to conduct studies that establish a minimum one-year estimate for the viable population size of Baker’s larkspur, while noting that PVT is not applicable Additionally, develop a comprehensive genetics management plan based on these results.
3 4.1.3 Conduct research to determine if hybridization occurs between Baker’s larkspur and other common co-occurring
3 mo PVT N/A 80 Approximate lump sum estimate for average genetic study
Conduct experimental plantings to assess whether outplanting Baker’s larkspur alongside compatible woody species enhances transplant survival rates Additionally, investigate if co-planting other native species attracts appropriate pollinators and leads to improved seed set.
5 yrs UCBG 0.4 2 Conducted in association with Action 2.2 No additional cost for field time- only for data analysis 1 day/yr x 5 yrs x
3 4.3 Periodically during the implementation of recovery actions above, determine whether sufficient information exists to describe conditions necessary for the delisting of Baker’s larkspur and develop delisting criteria accordingly.
Marin County work crews and fire crews at historical population site in regards to protection of Baker’s larkspur populations
Priority 1 actions: $722,050 Priority 2 actions: $126,790 Priority 3 actions: $85,000
Literature Cited
Abrams, L 1944 Illustrated flora of the Pacific States, Vol 2: Buckwheats to Kramerias Stanford University Press, Stanford, California.
Baye, P 2006 California sea-blite (Suaeda californica) reintroduction plan, San Francisco Bay, California Report to U.S Fish and Wildlife Service, Sacramento Field Office, August 2006 59 pp
Best, C., J.T Howell, W Knight, I Knight, and M Wells 1996 A Flora of Sonoma County California Native Plant Society Press, Sacramento, California.
California Natural Diversity Data Base (CNDDB) 2008 Occurrences of Delphinium bakeri 3 pp
Cayan, D., M Dettinger, I Stewart, and N Knowles 2005 Recent changes towards earlier springs: early signs of climate warming in western North America? U.S Geological Survey, Scripps Institution of Oceanography, La Jolla, California
The 2009 report by Cayan et al presents climate change scenarios and sea level rise estimates for California, highlighting the potential impacts of climate change on the region This assessment, conducted by the California Climate Change Center, provides crucial insights into future climate conditions and their implications for environmental and societal challenges in California.
Center for Plant Conservation (CPC) 2008 CPC National Plant Collection Plant Profile,
Delphinium bakeri http://www.centerforplantconservation.org/ASP/CPC_ViewProfile.asp?
Ellstrand N.C and D.R Elam 1993 Population genetic consequences of small population size: implications for plant conservation Annual Review of Ecology and Systematics 24: 217-242.
Ewan, J 1942 The genus Delphinium in North America: series Echinatae of subsection
Subscaposa, and miscellaneous noteworthy species Bulletin of the Torrey Botanical Club
In their 1999 report, "Confronting Climate Change in California," the Union of Concerned Scientists and the Ecological Society of America highlight the ecological impacts of climate change on the Golden State The authors, including Field, Daily, Davis, Gaines, Matson, Melack, and Miller, emphasize the urgent need for action to address these environmental challenges facing California.
Flora of North America Editorial Committee (Flora), (eds.) 1993+ Flora of North America North of Mexico Vol 3: Magnoliidae and Hamamelidae New York and Oxford.
Guerrant, Edward O 1996 Designing populations: Demographic, genetic, and horticultural dimensions In: D A Falk, C I Millar and M Olwell (eds.) Restoring diversity: strategies for reintroduction of endangered plants, edited by D A Falk, C I Millar and M Olwell
Harper, J.L 1977 Population Biology of Plants Academic Press, London Elsevier Science &
Hickman, J C (ed.) 1993 The Jepson Manual: Higher Plants of California University of
Howell, J.T 1970 Marin Flora University of California Press, Berkeley, California.
IPCC [Intergovernmental Panel on Climate Change] 2007 Climate change 2007: the physical science basis Summary for policymakers Contribution of Working Group I to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change, IPCC Secretariat, World Meteorological Organization and United Nations Environment Programme, Geneva,
Koontz, J.A and H Forbes 2003 Demography and conservation genetics of the endangered
Baker’s Larkspur (Delphinium bakeri, Ranunculaceae) Prepared for the Species Conservation and Recovery Program, Habitat Conservation Planning Branch, California Department of Fish and Game Research Permit 01-01 20 pp.
Mader, E., M Shepherd, M Vaughan, S.H Black, and G LeBuhn 2011 Attracting Native
Pollinators; Protecting North America’s Bees and Butterflies The Xerces Society, Storey
Publishing, North Adams, MA 339 pp + appendices.
Menges, E.S 1991 The application of minimum viable population theory to plants Pages 45-61 in: D.A Falk and K.E Holsinger (editors.) Genetics and conservation of rare plants Oxford University Press, New York, New York.
Munz, P.A and D.D Keck 1959 A California Flora University of California Press, Berkeley,
NEPCoP (New England Plant Conservation Program) 1992 New England Wild Flower
Pavlik, B l996 Defining and measuring success In: Falk, D., C Miller, and M Olwell, (eds.) Restoring Diversity, Strategies for Reintroduction of Endangered Plants Island Press,
Primack, R 1993 Essentials of Conservation Biology Sinauer and Associates Sunderland, MA Pp 253-276.
Schaffer, M.L 1981 Minimum population sizes for species conservation Bioscience 31.2:: 131-134.
U.S Fish and Wildlife Service 1983 Endangered and threatened species; listing and recovery priority guidelines Federal Register 48:43098-43105.
U S Fish and Wildlife Service 2000 Endangered and threatened wildlife and plants; determination of endangered status for two larkspurs from coastal northern California Federal
U S Fish and Wildlife Service 2003 Endangered and threatened wildlife and plants; final designation of critical habitat for two larkspurs from coastal northern California Federal
California Department of Fish and Game 1993 EPP Telecon report Telephone conversation record 2 pp.
Forbes, Holly 2011a Curator, UC Berkeley Botanical Garden Electronic mail from Holly
Forbes to Valary Bloom in regards to Baker’s larkspur reintroduction success monitoring. May 20, 2011.
Forbes, Holly 2011b Curator, UC Berkeley Botanical Garden Electronic mail from Holly
Forbes to Valary Bloom in regards to slug deterrent measures at Baker’s larkspur reintroduction sites September 7, 2011.
Forbes, Holly 2011c Curator, U.C Berkeley Botanical Garden Electronic mail from Holly
Forbes to Valary Bloom in regards to success of seed set, threats to Baker’s larkspur, and genetic introgression September 23, 2011.