CPC National Collection Plant Profile

Erigeron decumbens var. decumbens

Photographer:
Jimmy Kagan

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CPC National Collection Plant Profile

Erigeron decumbens var. decumbens


Family: 
Asteraceae  
Common Names: 
Willamette daisy, Willamette Valley daisy, Williamette fleabane
Author: 
Nutt.
Growth Habit: 
Forb/herb
CPC Number: 
1634

Distribution
Protection
Conservation
References


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Erigeron decumbens var. decumbensenlarge
Photographer: Jimmy Kagan
jimmy.kagan[at]oregonstate.edu


Erigeron decumbens var. decumbens is Fully Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Edward Guerrant, Ph.D. contributed to this Plant Profile.

 
Erigeron decumbens var. decumbens


Today, less than one present of Prairie land in the Willamette Valley remains in western Oregon and southwestern Washington. Consequently, the once common Willamette daisy (Erigeron decumbens ssp. decumbens) has nearly become extinct.

Not seen since 1934, Erigeron decumbens ssp. decumbens was thought extinct until 1980, when two populations were discovered. Although more populations have subsequently been found, this species continues to be at risk. In 1986 the largest population ever known (>6000 plants) was destroyed by plowing. The current 18 populations contain a mere 7500 plants, and only 4 of these remaining populations are on federal or city land and therefore legally protected from development.

Post-colonization land use practices are responsible for the destruction and fragmentation of the oak-savanna ecosystem. Both flooding and occasional fires helped to preserve the prairie habitat. The Native Americans that initially made the Willamette Valley their home managed prairies by setting fires in order to increase the abundance of food plants and for ease of hunting. This kept ash, rose, blackberry, conifers and other woody species from invading.

Since European settlement, vast tracts of Willamette Valley Prairie have been converted to agricultural production or human habitation. Due to fire suppression efforts, much of the remaining areas have been converted to dense thickets of brush or trees. The Willamette daisy has not been found in any areas currently grazed or farmed, but is sometimes found in places that were formerly grazed or farmed, providing encouragement that restoration efforts could be successful.


Distribution & Occurrence

State Range
  Oregon
State Range of  Erigeron decumbens var. decumbens
Habitat
  • Heavy soils in seasonally wet native or dry upland prairie grasslands (Meinke 1982; Kagan and Yamamoto 1987).
• Associated species include Aster hallii, Festuca sp., Danthonia sp., Rhus diversiloba, Hypericum perforatum, and Aira caryophyllea (Meinke 1982).

Distribution
  OR: Willamette Valley

Number Left
  As of 1993: 18 populations were known, with two on federal land and two on city owned land. These four populations are the only legally protected from development. Since it is difficult to distinguish genetically distinct plants, "clumps" of plants were counted. There were approximately 7500 clumps observed in 1993. Populations ranged in size from 1 individual to 2080 "clumps" (Clark et al. 1993).

Protection

Global Rank:  
G4T1
 
7/9/2007
Guide to Global Ranks
Federal Status:  
LE
 
1/25/2000
Guide to Federal Status
Recovery Plan:  
No
 

State/Area Protection
  State/Area Rank Status Date  
  Oregon S1 LE 7/12/1995  

Conservation, Ecology & Research

Ecological Relationships
  Erigeron decumbens is an early successional species that is dependent on flooding and fire to maintain open prairie habitats (Kagan and Yamamoto 1987). Fire prevents native shrubs and trees from encroaching and out-competing shade intolerant plants, such as the Willamette Daisy.

This rare species spreads vegetatively via rhizomes over very short distances about 4 inches (<10cm) (Kaye 2000). Since plants often grow in clumps, it is often difficult to distinguish individuals. Sexual reproduction is facilitated by pollination by insects, including the field crescent butterfly, sweat bees, and a syrphid fly. Seeds are dispersed by wind, but the small size and number of pappus bristles leads to more localized dispersal (Kagan and Yamamoto 1987).

Laboratory testing reveals that scarification stimulates germination. The mechanism for seed coat scarification in the wild is unknown, but researchers hypothesize that soil microbes may break down the coat during the winter (Clark et al, 1997). Most germination of E. decumbens seeds occur in April and May (Clark et al. 1997). Flowering in concentrated in June and early July, and seeds are dispersed in mid to late July (Ingersoll et al. 1995).

Threats
  • Agricultural and urban expansion (Meinke 1982).
• Unmonitored burning (infrequent, hot fires) (Meinke 1982).
• Secondary succession (Kagan and Yamamoto 1987).
• Road construction and maintenance (Clark et al. 1993).
• Invasive non-native plants, especially Brachypodium sylvaticum (Clark et al. 1993).

Current Research Summary
  Seed germination and viability tests:
• Germination trials. Results indicated that scarification is required for germination (Clark et al. 1995). Other studies show that cold stratification can be used instead of scarification.

Propagation studies:
• Erigeron decumbens ssp. decumbens can be propagated using above stem cuttings, but success rates for establishment are much higher when vegetative cuttings include a small amount of rhizome tissue. Rhizome cuttings had survival rates if 67% at eight weeks and 33% at 26 weeks (Clark et al. 1997).
• Propagation and transplantation studies. Erigeron decumbens ssp. decumbens produced few seedlings when directly seeded, even at high density seeding (60 seeds/m2). Encouragingly, transplants had fairly high survival rates, ranging from 33% to 70%, depending on source population and fertilization treatment (Kaye et al. 2000). These transplantation rates were much higher than a previous study had found (Clark et al., 1997). Researchers from the first study noted that roots developed slowly and their high mortality rates were caused by desiccation.

Monitoring and Management studies:
• A five-year demographic study at three different sites did not help researchers identify optimal environmental conditions, due to a lack of gradient in environmental conditions. In most years, populations from both upland and lowland sites had similar reproductive output (Finley 1998). The five-year monitoring study did reveal a possible trend towards fewer reproductive plants and greater mortality at one site during the final year of monitoring (Finley 1998).
• Experimental burning over a four-year period at a Research Natural Area found that plants were negatively affected by burning in the first year. However, results were positive in subsequent years, as crown area and flowering increased relative to unburned plants (Connelly and Kauffman 1991, Finley and Kauffman 1992 in Clark et al. 1993).

• Germination trials at The Berry Botanic Garden resulted in 78% germination of apparently good seeds when subjected to eight weeks of cold stratification followed by alternating 50°F/68°F (10°C/20°C) and 60% when apparently good seeds were subjected to eight weeks of cold stratification followed by constant 68°F (20°C). Seeds not cold stratified did not germinate (BBG File).
• Germination trials conducted. Germination was essentially zero with no cold treatment, and increased steadily with the duration of cold stratification. Twelve weeks of cold stratification yielded germination from 13% to 44% depending on seed source. Since this species' small seed size makes manual scarification difficult, cold stratification may be a more effective method when germinating large numbers of seed (Kaye and Kuykendall 2000).
• Germination and viability studies. Addition of Gibberellic acid (GA) (a plant hormone that plays a role in the regulation of seed germination and dormancy) increased germination rates in scarified seeds from 1993. Scarified seeds from 1994 did not have the same response. One hypothesis is that the 1993 seeds underwent after-ripening and were more receptive to GA. There was not an increase in germination rate with GA addition for either seeds that were not scarified or those that had received cold treatment (Clark et al. 1997).
• Seed viability studies. The viability of E. decumbens seeds that appeared to have a developed embryo ranged from 60-70%. However, overall production of seeds with embryos was only between 2-19% of total seed production. Seed viability did not decline after one year of storage (Clark et al. 1997).

Current Management Summary
  • Prescribed burning at federally owned sites. However, this conflicts with air quality standards. The surrounding area is burned for the grass seed producers and it is difficult for conservation groups to obtain permits for prescribed burns as it is feared it will add to the air pollution problem (Kagan and Yamamoto 1987).
• Manual and mechanical removal of encroaching trees (Kagan and Yamamoto 1987).
• Base-line data is being collected to determine effects of future management treatments such as mowing and burning on BLM land (Kaye 2000).
• Seed from at least 5 of the 18 locations are stored at The Berry Botanic Garden.

Research Management Needs
  • Long term demographic monitoring to determine information on vegetative growth, reproduction, recruitment, and mortality (Finley et al. 1995). Close monitoring of Baskett Butte population, to determine the effect of diminished reproductive output observed (Finely 1998).
• Determine if low rate of filled seed production is a consistent pattern and investigate what factors influence production of viable seed (Clark et al. 1997).
• Determine seed scarification mechanism in the wild to develop a practical method for laboratory scarification and assist in restoration efforts (Clark et al. 1997).
• Determine appropriate frequency of prescribed burning (Clark et al. 1993).
• Determine extent of clonality via genetic analysis.

Ex Situ Needs
  • Collect and store seeds from across the range.
• Seed viability testing, germination temperature and condition optimization, and methods of transplantation (Finley et al. 1995).

References

Books (Single Authors)

Eastman, D.C. 1990. Rare and Endangered Plants of Oregon. Beautiful America Publishing Company. 194p.

Meinke, R.J. 1982. Threatened and Endangered Vascular Plants of Oregon: An Illustrated Guide. Portland, Oregon: U.S. Fish & Wildlife Service, Region 1. 326p.

ONHP. 2001. Rare, Threatened and Endangered Plants and Animals of Oregon.

Books (Sections)

Clark, D.L.; Ingersoll, C.A.; Finley, K.K. 1997. Regeneration of Erigeron decumbens var. decumbens (Asteraceae), the Willamette daisy. In: Kaye, T.N.; Liston, A.; Love, R.N.; Luoma, D.L.; Meinke, R.J.; Wilson, M.V., editors. Conservation and management of native plants and fungi. Native Plant Society of Oregon. Corvallis, Oregon. p 41-47.

Books (Edited Volumes)

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

Electronic Sources

ONHDB. (2000). Oregon Natural Heritage Program Database. Portland, Oregon.

Journal Articles

1840. (Original Publication). Trans. Am. Phil. Soc. II. 7: 309.

McMahan, L.R. 2000. The Endangered Plants of Portland & Surrounding Areas. The Berry Botanic Garden Newsletter. 13, 1: 4-5.

USFWS. 2000. Endangered Status for Erigeron decumbens var. decumbens (Willamette Daisy) and Fender’s Blue Butterfly (Icaricia icarioides fenderi) and Threatened Status for Lupinus sulphureus ssp. kincaidii (Kincaid’s Lupine). Federal Register. 65, 16: 3875-3890.

USFWS. 2000. Proposed Endangered Status for Erigeron decumbens var. decumbens (Willamette Daisy) and Fender’s Blue Butterfly (Icaricia icarioides fenderi) and Threatened Status for Lupinus sulphureus ssp. kincaidii (Kincaid’s Lupine). Federal Register. 63, 17: 3863-3877.

USFWS. 2000. Regional News, Recovery Updates, & Listing Actions. Endangered Species Technical Bulletin. 25, 1-2: 1-7.

Newspaper Articles

2001 June 14, 2001. Holding on for Life: Local endangered species survive in isolated patches. Eugene Weekly-Online Edition; Volume XX No. 24.

Reports

Clark, D.L. 2000. Demographic analysis of Erigeron decumbens var. decumbens, an endangered plant species of the Willamette Valley, Oregon: 1999 Field Studies. U.S. Fish and Wildlife Service, Western Oregon NWR Refuge Complex. Order No. 1448-13590-9-M047A.

Clark, D.L.; Finley, K.K.; Ingersoll, C.A. 1993. Status report for Erigeron decumbens var. decumbens. Unpublished report prepared for the Conservation Biology Program, Oregon Department of Agriculture. p.55+.

Clark, D.L.; Finley, K.K.; Ingersoll, C.A. 1995. Regeneration biology of Erigeron decumbens var. decumbens, an endangered plant of the Willamette Valley. Salem, OR: Prepared for the Oregon Department of Agriculture, Plant Conservation Biology Program. p.24+.

Finely, K.K. 1998. Field Monitoring of Erigeron decumbens decumbens (the Willamette Daisy). Final Report prepared for the U.S. Fish and Wildlife Service. p.10.

Finley, K.K.; Clark, D.L.; Ingersoll, C.A. 1995. Research Plan: Recommendations for future research and monitoring of Erigeron decumbens var. decumbens (the Willamette daisy). Report prepared for the Oregon Department of Agriculture, Plant Conservation Biology Program. p.5.

Finley, K.K.; Kauffman, J.B. 1992. Soils and hydrology of Willamette Valley wetland prairies and ecological response of Lomatium bradshawii and Erigeron decumbens var. decumbens to prescribed fire. Eugene, Oregon: A progress report to the U.S. Army Corps of Engineers and the Bureau of Land Management.

Ingersoll, C.A.; Finley, K.K.; Clark, D.L. 1993. A monitoring program for Erigeron decumbens var. decumbens, a Willamette Valley Endemic. Salem, Oregon: Report to the Conservation Biology Program, Oregon Department of Agriculture.

Ingersoll, C.A.; Finley, K.K.; Clark, D.L. 1995. Demography and Reproduction of Erigeron decumbens var. decumbens, 1993-1994 Field Studies. Prepared for the Oregon Department of Agriculture, Plant Conservation Biology Program. p.28.

Kagan, J.S.; Yamamoto, S. 1987. Status Report for Erigeron decumbens subsp. decumbens (Draft). Oregon Natural Heritage Data Base. p.30+.

Kaye, T.N. 2000. Population Monitoring for Proposed Experimental Habitat Manipulation of Willamette Daisy, Oxbow West Site, West Eugene. Challenge Cost Share Project funded jointly by the Bureau of Land Management, Eugene District and the Institute for Applied Ecology. p.15.

Kaye, T.N. 2001. Population Monitoring for Proposed Experimental Habitat Manipulation: Willamette daisy, Oxbow West Site, West Eugene. Corvallis, Oregon: Institute for Applied Ecology. p.14 + appendices. Progress Report.

Kaye, T.N.; Kuykendall, K. 2000. Germination and propagation of rare Willamette Valley prairie plants. Challenge Cost Share Project funded jointly by the Bureau of Land Management, Eugene District and Plant Conservation Biology Program, Oregon Department of Agriculture. p.16.

Kaye, T.N.; Kuykendall, K.; Nelson, C. 2000. Seedling and transplanting rare Willamette Valley prairie plants for population restoration. Challenge Cost Share Project funded jointly by the Bureau of Land Management, Eugene District and the Institute for Applied Ecology. p.42.

Wilson, M.V.; Connelly, K.P.; Lantz, Lisa E. 1993. Plant Species, Habitat, and Site Information for Fern Ridge Reservoir. A Component of the Project to Develop Management Guidelines for Native Wetland Communities. Submitted to Waterways Experiment Station, Army Corps of Engineers, Vicksburg, Mississippi AND Soil Conservation Service, Portland, Oregon by Restoration Ecology and Plant Conservation Biology Cooperative Project, Department of Botany and Plant Pathology, and Department of Rangeland Resources, Oregon State University.

Wilson, M.V.; Hammond, Paul C.; Christy, John A.; Clark, Deborah L.; Merrifield, Kathy; Wagner, David H. 1998. Upland Prairie. Contributed Chapter: Part I the U.S. Fish and Wildlife Service Willamette Basin Recovery Plan. U. S. Fish and Wildlife Service, Oregon State Office. Order no. 13420-6-0287 (2).

Wilson, M.V.; Hammond, Paul C.; Christy, John A.; Clark, Deborah L.; Merrifield, Kathy; Wagner, David H. 1998. Wetland Prairie. Contributed Chapter: Part I the U.S. Fish and Wildlife Service Willamette Basin Recovery Plan. U. S. Fish and Wildlife Service, Oregon State Office. Order no. 13420-6-0287 (2).

Theses

Leininger, S. 2001. Promoting and restoring Kincaid's lupine (Lupinus sulphureus ssp. kincaidii) and Willamette daisy (Erigeron decumbens var. decumbens) at Baskett Slough NWR. [Senior honors Thesis]:


  This profile was updated on 7/8/2010
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