CPC National Collection Plant Profile

Astragalus brauntonii

Photographer:
Bart O'Brien

Heading for profile page
CPC Home Join now
About CPC
CPC National Collection
Conservation Directory Resources
Invasive Plant Species Plant News
Plant Links Participating Institutions
Contribute
Search CPC
Search    Alphabetical List    Reference Finder    CPC Home


CPC National Collection Plant Profile

Astragalus brauntonii


Family: 
Fabaceae  
Common Name: 
Braunton's milkvetch
Author: 
Parish
Growth Habit: 
Forb/herb
CPC Number: 
374

Distribution
Protection
Conservation
References


Profile Links
 ITIS
 Tropicos
 PLANTS
 Fish & WildLife

Astragalus brauntoniienlarge
Photographer: Bart O'Brien
Image Owner: Personal


Astragalus brauntonii is Not Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Valerie Soza contributed to this Plant Profile.

 
Astragalus brauntonii


This is an ephemeral perennial member of the pea family that reaches a height of 15 dm with dull lilac flowers blooming March-July (Munz 1974). It typically appears following a chaparral fire or other form of mechanical disturbance and persists several years before senescing or becoming crowded out by developing vegetation (Skinner 1991). Braunton's milkvetch seeds persist in the soil bank for many years and have a seed coat that is typical of many chaparral plants and adapted to germinate after some form of disturbance which breaks seed dormancy (USFWS 1999).

Distribution & Occurrence

State Range
  California
State Range of  Astragalus brauntonii
Habitat
  Braunton's milkvetch generally occurs below 2100 feet (640 m) in elevation, on south-, west-, and east-facing slopes, in open areas within chaparral. It is often found growing in disturbed areas such as burn areas, along fire roads or fuel breaks, and in areas that have been cleared by some means and where competition is low. This plant was historically found in gravelly clay soils overlaying granite sandstone, but is now found often associated with carbonate soils derived from scattered limestone lenses, or on noncarbonates at down-wash sites (Skinner 1991; USFWS 1999).

Distribution
  Braunton's milkvetch is known to occur only in the hills bordering the Los Angeles basin in southern California, from Ventura, Los Angeles, and Orange counties. Known occurrences of this species are in the Simi Hills of Ventura and Los Angeles counties, the Santa Monica Mountains and San Gabriel Mountains in Los Angeles County, and the Santa Ana Mountains in Orange County.

Number Left
  There are 16 known extant occurrences of Braunton's milkvetch, with 12 historical occurrences that have been extirpated of presumed extirpated (CNDDB 2001). Braunton's milkvetch is currently known from four general areas in Ventura, Los Angeles, and Orange counties: eastern end of Simi Hills, eastern half of the Santa Monica Mountains, southern base of the San Gabriel Mountains, and northwestern side of the Santa Ana Mountains.

Protection

Global Rank:  
G2
 
7/24/2003
Guide to Global Ranks
Federal Status:  
LE
 
1/29/1997
Guide to Federal Status
Recovery Plan:  
Yes
 
9/30/1999

State/Area Protection
  State/Area Rank Status Date  
  California S2.1 5  

Conservation, Ecology & Research

Ecological Relationships
  Pollinators that have been observed on Braunton's milkvetch are mostly native megachild bees, followed by native bumble bees (USFWS 1999).

Threats
  The major threat to this species is immediate loss of native habitat. Most of the habitat is on private lands or in the immediate vicinity of areas of expanding urban development, including construction of housing, golf courses and infrastructure.
In addition, occurrences along fire roads, fuelbreaks, and trails are also susceptible to trampling from hikers, off-road vehicles, and equestrian use.
Other threats include alteration of habitat resulting from a change in the natural fire cycle, stochastic events, overcollecting, habitat fragmentation and degradation competition from invasive weeds.

Current Research Summary
  USFWS section 6 funding was provided for a 1998 study of the ecology and distribution of Braunton's milkvetch, in particular soil seed bank characteristics and pollination requirements (USFWS 1999). In addition, Rancho Santa Ana Botanic Garden has undertaken preliminary germination and growth experiments for possible introduction efforts (Hannon pers. comm.)

Current Management Summary
  Currently, the southern California National Forests are developing suitable habitat models for this species to identify areas on National Forest System Lands that could potentially support additional occurrences of Braunton's milkvetch and to determine whether this taxon is present or absent within these areas and if present, manage populations accordingly.

Research Management Needs
  More surveys are needed in suitable habitat post-fire or after some other disturbance to locate additional populations of Braunton's milkvetch. Seeds remain in the soil bank for many years before germinating and therefore, other areas that have not burned in many years could potentially support additional occurrences of this plant. Fire suppression regimes need to be reevaluated in areas of suitable habitat. In the meantime, suitable habitat should be secured and then burned periodically to stimulate germination of potential seed (Skinner 1991).

Ex Situ Needs
  Because Braunton's milkvetch seed remains dormant in the soil bank for many years, there is more likely to be a higher amount of genetic diversity in the seed bank than in living plant populations. Seed should be collected from newly-discovered populations and stored at established conservation seed programs. Existing populations should be monitored annually and seed should also be collected from newly-established individuals to increase the genetic diversity and gene pool for this species stored at conservation seed programs.

References

Books (Single Authors)

Barneby, R.C. 1964. Atlas of North American Astragalus. Bronx, New York: New York Botanical Garden. 1188p.

Munz, P.A. 1974. A flora of southern California. Berkeley: Univ. California Press. 1086p.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Books (Edited Volumes)

James C. Hickman, Editor. 1993 The Jepson manual: Higher plants of California. Berkeley: University of California Press. 1400p.

Electronic Sources

CNDDB. (2000). Calfornia Natural Diversity Data Base (CNDDB). Version 2.1.2. California Natural Diversity Database. Accessed: California Department of Fish and Game, Sacramento.

USFWS. (2002). Threatened & Endangered Plants Within Ventura Field and Wildlife Office Area of Responsibility. U.S. Fish and Wildlife Service, Ventura Fish and Wildlife Office. http://ventura.fws.gov/plant.html. Accessed: 2002.

Journal Articles

Skinner, M. 1991. Rare plants of California: Braunton's milkvetch. Fremontia. 19, 3: 6-7.

USFWS. 1997. Determination of endangered status for two plants and threatened status for four plants from southern California. Federal Register. 62, 19: 4172-4183.

Personal Communications

Hannon, D. 2001. Rancho Santa Ana Botanic Garden , Plant Propagator, personal communication.

Reports

Stephenson, John R.; Calcarone, Gena M. 1999. Southern California Mountains and Foothills Assessment: Habitat and Species Conservation Issues. Chapter 5 - Potentially Vulnerable Species: Plants. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. p.402. General Technical report PSW-GTR-172.

USFWS. 1999. Recovery Plan for Six Plants from the Mountains Surrounding the Los Angeles Basin. Portland, Oregon: U.S. Fish and Wildlife Service. p.63.


  This profile was updated on 3/4/2010
California
Oregon
Washington
Idaho
Nevada
Arizona
Utah
Montana
Wyoming
Colorado
New Mexico
North Dakota
South Dakota
Nebraska
Kansas
Oklahoma
Texas
Minnesota
Iowa
Missouri
Arkansas
Louisiana
Wisconsin
Illinois
Michigan
Michigan
Indiana
Ohio
Kentucky
Tennessee
Mississippi
Alabama
Florida
Georgia
South Carolina
North Carolina
Virginia
West Virginia
Pennsylvania
Delaware
Maryland
New Jersey
Connecticut
Rhode Island
Massachusetts
Vermont
New Hampshire
Maine
New York
New York
Hawaii
Hawaii
Hawaii
Hawaii