Applegate's Milkvetch / Center For Plant Conservation
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Plant Profile

Applegate's Milkvetch (Astragalus applegatei)

Astragalus applegatei in bloom. Photo Credit: Kagan/Yamamoto
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Fabaceae
  • State: OR
  • Nature Serve ID: 156762
  • Lifeform: Forb/herb
  • Date Inducted in National Collection: 02/10/1987
Description:

In the mid-1980s, a significant portion of the largest remaining Applegate's milkvetch population was paved over to make way for an auto dealership and grocery store. Since the site, which was just outside Klamath Falls, Oregon, contained the largest remaining population, this destruction was especially detrimental to the future of this species. Even before this unfortunate event, however, Applegate's milkvetch had reached a critical point. Land development, noxious weed introduction, and the suppression of fires within its limited range had dramatically reduced suitable habitat. Consequently, Applegate's milkvetch is only found at three sites. Of the approximately 12,000 individuals that remain, nearly all are found at the one location outside of Klamath Falls. While conservation efforts are underway, Applegate's milkvetch is still severely threatened. The Nature Conservancy purchased a portion of the land that contains the vital Klamath Falls population, but the remaining area is still at risk of development. Alarmingly, this protected population has decreased to fewer than 8,000 individuals. The other two locations are on public lands and are protected by its listing as Endangered by the Fish and Wildlife Service. Nevertheless, these two sites contain very few individuals, only 500 and 3, respectively. Due to these small population sizes, persistence is uncertain as these sites are especially susceptible to random disturbance and the lack of genetic variation may cause problems associated with inbreeding. Applegate's milkvetch is distinguishable in mid-summer by its small, whitish flowers with purple tips. This plant is also unique because it is only found in flat, seasonally moist meadows and flood plains of the Lower Klamath Basin. The US Fish and Wildlife Service has developed a recovery plan that aims to increase the number of plants to six populations with a minimum of 4,500 plants each. At that point, Applegate's milkvetch will be considered for downlisting to threatened status.

Where is Applegate's Milkvetch (Astragalus applegatei) located in the wild?

Habitat:

Flat, open, seasonally moist remnants of floodplain alkaline grassland of the Klamath Basin (Williams and Parenti 1991, USFWS 1997). Habitat was historically characterized by sparse, native bunch grass and patches of bare soil (USFWS 1997). Elevation 4,100 ft (1250 m).

Distribution:

Oregon, East Cascades geographic province- Presently only found at three locations all within the lower Klamath Basin. A fourth population existed about 10 miles SW of Klamath Falls, indicating this

States & Provinces:

Applegate's Milkvetch can be found in Oregon

Which CPC Partners conserve Applegate's Milkvetch (Astragalus applegatei)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

  • 08/20/2020
  • Propagation Research

1,500 individuals were cultivated for introduction to the Klamath Wildlife Area. Seeds were collected from the Klamath Wildlife Area population being augmented. Despite consistently high (~ 90%) germination rates after scarification, the fungal root pathogen Fusarium oxysporum stunted growth and greatly reduced the number of plants available for outplanting. Fungicide, fertilization, and irrigation treatment failed to decrease infection. In all cases, only 12 and 14% of plants were usable, and even those plants available for outplanting were of questionable vigor. Of these plants, few survived one growing season (Gisler and Meinke 1998).

  • 08/20/2020
  • Reintroduction

1,500 individuals were cultivated for introduction to the Klamath Wildlife Area.

  • 08/20/2020
  • Genetic Research

Low seed sets among irrigated, fertilized, greenhouse-grown, and hand-pollinated plants suggest that low seed set is not a result of water or macronutrient deficiency, but rather may be limited by intrinsic genetic factors, possibly inbreeding depression, or other resource limitations (USFWS 1997).

  • 08/20/2020
  • Reproductive Research

Low seed sets among irrigated, fertilized, greenhouse-grown, and hand-pollinated plants suggest that low seed set is not a result of water or macronutrient deficiency, but rather may be limited by intrinsic genetic factors, possibly inbreeding depression, or other resource limitations (USFWS 1997). Greenhouse experiments revealed that native soil inoculation was successful at facilitating abundant colonization of mycorrhizal fungi. Plants were grown in both non-inoculated and inoculated soil, and only those plants from the inoculation treatment survived (Barroetavena et al. 1998). Growth and survival of individuals grown under greenhouse conditions in six experimental soil treatments were compared: 1) field soil from natural habitat, 2) field soil subjected to heat sterilization (control treatment), 3) field soil treated with fungicide, 4) commercial grade Rhizobium inoculum, 5) commercial grade mycorrhizal (VAM) inoculum, and 6) mixture of commercial grade Rhizobium + VAM inoculate. Plants were not fertilized. Results from the trials clearly indicate that A. applegatei grew best under the field soil treatment. Astragalus applegatei grown under the field soil treated with fungicide treatment performed slightly better than the control and commercial inoculum treatment, but not nearly as well as the untreated field soil treatment (Gisler and Meinke 2001). Growth and survival of individuals grown with sterilized soil inoculated with a small amount of field soil were compared. Only one tablespoon of field soil was needed to promote healthy growth for each individual, posing little threat of depleting natural populations of their soil. Alternatively, a self-sustainable source of inoculum can be developed from a field soil inoculum starter in the greenhouse using other species of host plants (Gisler and Meinke 2001). Germination trials at The Berry Botanic Garden. For scarified seeds, all treatments (Either 8 weeks cold stratification or no cold stratification and either constant 68F (20C) or alternating 50/68F (10/20 C) treatments yielded between 40 and 60 % germination (BBG File).

  • 08/20/2020
  • Propagation Research

Germination trials at The Berry Botanic Garden. For scarified seeds, all treatments (Either 8 weeks cold stratification or no cold stratification and either constant 68F (20C) or alternating 50/68F (10/20 C) treatments yielded between 40 and 60 % germination (BBG File).

  • 08/20/2020
  • Demographic Research

As of 1998: 3 populations: One with 11,500 individuals (seven acres with the greatest number and density of plants is owned and managed by The Nature Conservancy, while the remainder is on private land). Another with fewer than 500 individuals (owned and managed by the Oregon Department of Fish and Wildlife). A third with only 3 plants (discovered in 1997) (USFWS 1998). 1,500 individuals were cultivated for introduction to the Klamath Wildlife Area. Seeds were collected from the Klamath Wildlife Area population being augmented. Monitoring at the site managed by The Nature Conservancy. At this site, recruitment is decreasing and seedlings have become rare within the macroplots that were established in 1988 for long term monitoring. This population initially showed an increase from 1988 to 1991, when it hit a high at nearly 30,000 estimated individuals. Since 1995, the population has been hovering at lowest record levels of abundance (between ~4,500 to ~10,000 individuals). Though poorly documented, distribution of Astragalus applegatei individuals outside the macroplot suggests that the population may be expanding westward. It is important to note that the suitability of habitat is this new area is questionable, and that slow dispersal rate may limit the extent of colonization (Borgias 2001). Seed from one population is stored at The Berry Botanic Garden.

  • 08/20/2020
  • Orthodox Seed Banking

Seed from one population is stored at The Berry Botanic Garden.

  • 08/20/2020
  • Seed Collection

1,500 individuals were cultivated for introduction to the Klamath Wildlife Area. Seeds were collected from the Klamath Wildlife Area population being augmented.

Nature Serve Biotics
  • 05/02/2017

Limited range with a small number of extant populations. Threatened from fragmentation and loss of habitat, potential development and road construction, elimination of the natural seasonal flooding regime along the floodplains supporting the species, suppression of fire, invasive exotic plants, and insect usage. Two sites are threatened by rabbit grazing.

Edward Guerrant, Ph.D.
  • 01/01/2010

Habitat conversion to fields and pasture (Meinke 1982 & USFWS, 1998). Commercial development on habitat of largest (and only genetically viable) population. Negotiations to lease the land from the owner were unsuccessful. The area is now an auto

Edward Guerrant, Ph.D.
  • 01/01/2010

As of 1998: 3 populations: One with 11,500 individuals (seven acres with the greatest number and density of plants is owned and managed by The Nature Conservancy, while the remainder is on private land). Another with fewer than 500 individuals (owned and managed by the Oregon Department of Fish and Wildlife). A third with only 3 plants (discovered in 1997) (USFWS 1998).

Edward Guerrant, Ph.D.
  • 01/01/2010

Low seed sets among irrigated, fertilized, greenhouse-grown, and hand-pollinated plants suggest that low seed set is not a result of water or macronutrient deficiency, but rather may be limited by intrinsic genetic factors, possibly inbreeding depression, or other resource limitations (USFWS 1997). Greenhouse experiments revealed that native soil inoculation was successful at facilitating abundant colonization of mycorrhizal fungi. Plants were grown in both non-inoculated and inoculated soil, and only those plants from the inoculation treatment survived (Barroetavena et al. 1998). Growth and survival of individuals grown under greenhouse conditions in six experimental soil treatments were compared: 1) field soil from natural habitat, 2) field soil subjected to heat sterilization (control treatment), 3) field soil treated with fungicide, 4) commercial grade Rhizobium inoculum, 5) commercial grade mycorrhizal (VAM) inoculum, and 6) mixture of commercial grade Rhizobium + VAM inoculate. Plants were not fertilized. Results from the trials clearly indicate that A. applegatei grew best under the field soil treatment. Astragalus applegatei grown under the field soil treated with fungicide treatment performed slightly better than the control and commercial inoculum treatment, but not nearly as well as the untreated field soil treatment (Gisler and Meinke 2001). Growth and survival of individuals grown with sterilized soil inoculated with a small amount of field soil were compared. Only one tablespoon of field soil was needed to promote healthy growth for each individual, posing little threat of depleting natural populations of their soil. Alternatively, a self-sustainable source of inoculum can be developed from a field soil inoculum starter in the greenhouse using other species of host plants (Gisler and Meinke 2001). Germination trials at The Berry Botanic Garden. For scarified seeds, all treatments (Either 8 weeks cold stratification or no cold stratification and either constant 68F (20C) or alternating 50/68F (10/20 C) treatments yielded between 40 and 60 % germination (BBG File).

Edward Guerrant, Ph.D.
  • 01/01/2010

Protection from grazing, vehicular traffic, development on site managed by Oregon Department of Fish and Wildlife (USFWS 1997). Grazing does occur at the Klamath Wildlife Area (Gisler and Meinke 1998). Experimental prescribed burning, herbicide application, and mowing at site managed by The Nature Conservancy to examine the influence of invasive species on Astragalus applegatei populations (USFWS 1997) Recovery plan finalized in 1998. 1,500 individuals were cultivated for introduction to the Klamath Wildlife Area. Seeds were collected from the Klamath Wildlife Area population being augmented. Despite consistently high (~ 90%) germination rates after scarification, the fungal root pathogen Fusarium oxysporum stunted growth and greatly reduced the number of plants available for outplanting. Fungicide, fertilization, and irrigation treatment failed to decrease infection. In all cases, only 12 and 14% of plants were usable, and even those plants available for outplanting were of questionable vigor. Of these plants, few survived one growing season (Gisler and Meinke 1998). Monitoring at the site managed by The Nature Conservancy. At this site, recruitment is decreasing and seedlings have become rare within the macroplots that were established in 1988 for long term monitoring. This population initially showed an increase from 1988 to 1991, when it hit a high at nearly 30,000 estimated individuals. Since 1995, the population has been hovering at lowest record levels of abundance (between ~4,500 to ~10,000 individuals). Though poorly documented, distribution of Astragalus applegatei individuals outside the macroplot suggests that the population may be expanding westward. It is important to note that the suitability of habitat is this new area is questionable, and that slow dispersal rate may limit the extent of colonization (Borgias 2001). Seed from one population is stored at The Berry Botanic Garden.

Edward Guerrant, Ph.D.
  • 01/01/2010

Study levels of seedling recruitment, natural rates of plant development, plant longevity, and minimum population sizes required for long term survival (USFWS 1997). Study outcrossing rates, and relative fitness between individuals resulting from self- and cross-pollinated seeds (USFWS 1997). Research impacts of competition from weeds and other plants. Explore whether the presence of other plants facilitate pollination by attracting pollinators or reduces pollination due to competition for pollinators (USFWS 1997). Investigate the benefits of controlled burning (USFWS 1997). Determine alkalinity tolerance, and to what degree soil specialization may prevent competitive exclusion by other less alkaline-tolerant native taxa (USFWS 1997). Study salinity and hydrological tolerances (Borgias 2001). Identify the abundance and geographic distribution of soil symbionts. In habitats lacking such symbionts, it may be possible to inoculate sites with field soil from natural populations to increase potential habitat for A. applegatei (Gisler and Meinke 2001). Further research on the extent, impacts, and possible control of herbivory and predation (USFWS 1997). Study age structure and levels of recruitment population dynamics in order to assess the long-term viability of population in terms of age/growth stage structure (USFWS 1997). Monitor the westward expansion of A. applegatei at the site managed by The Nature Conservancy (TNC) population (Borgias 2001). Determine the long term effect of quackgrass colonization on the TNC Astragalus applegatei population (Borgias 2001). Investigate whether appropriate soil microfauna in field soil samples can survive dry frozen storage.

Edward Guerrant, Ph.D.
  • 01/01/2010

Collect and store seed from all known populations. Collect a few seeds over a period of years to reduce the impact of seed removal on the population. If techniques can be developed, collect and store field soil samples containing appropriate soil microflora to aid in population establishment or reintroduction.

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Nomenclature
Taxon Astragalus applegatei
Authority M.E. Peck
Family Fabaceae
CPC Number 368
ITIS 25418
USDA ASAP
Duration Perennial
Common Names Applegate's milkvetch | Applegate's milk-vetch
Associated Scientific Names Astragalus applegatei
Distribution Oregon, East Cascades geographic province- Presently only found at three locations all within the lower Klamath Basin. A fourth population existed about 10 miles SW of Klamath Falls, indicating this
State Rank
State State Rank
Oregon S1
Ecological Relationships

Photos
Pollinators
Common Name Name in Text Association Type Source InteractionID
Butterflies & Moths
Blues Plebejus melissa Confirmed Pollinator Link

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