United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Eryngium racemosum is endemic to California, where it is only known from delta and riverine habitats in Stanislaus, San Joaquin, and Merced counties. An occurrence associated with the shores of a reservoir in Calavaras County has been found to be erroneous; the plants were actually E. castrense.

Eryngium racemosum Jeps.:
United States (North America)

Prostrate habit; producing roots and juvenile leaves at the nodes; heads in racemes vs cymes.

There is some professional disagreement regarding the validity of this taxon. Eryngiums are notoriously difficult to distinguish; current taxonomic works recognize Eryngium racemosum as a valid species.

Holotype for Eryngium elongatum J.M. Coult. & Rose
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): G. R. Vasey
Year Collected: 1875
Locality: Near San Francisco., California, United States, North America

Comments: Eryngium racemosum occupies seasonally moist floodplain habitat that is fully drained following the spring runoff. Unlike other species of Eryngium in California, E. racemosum is not a vernal pool species. Populations are generally found on new floodplain on heavy clay soils which are low in pH (below pH=7). It has been speculated that the unique root system of E. racemosum is related to the frequent flooding and silt deposition in its habitat.

This species is known only from low elevation sites along the San Joaquin River and tributaries; elevations range up to about 100 feet with one occurrence found along a reservoir at 240 feet in Stanislaus County. This latter occurrence is somewhat suspect since a similar occurrence in Calaveras County by another reservoir was found to be the result of an erroneous identification.

Eryngium racemosum is nearly universally found with Lippia nodiflora (now Phyla nodiflora var. incisa and var. nodiflora). Another frequent companion at many populations is Hemizonia parryi. Other associates that have been mentioned include Salix goodingii, Plagiobothrys stipitatus, Deschampsia danthonioides, Sida hederacea, Distichlis spicata and Lotus purshianus. Two prominent weedy associates that can out-compete this rare plant are Helianthus annuus and Xanthium sp. (probably strumarium).

Eryngium racemosum is a herbaceous biennial that flowers from June to approximately September. This plant germinates following flood events in its habitat, which is located near streams and rivers in the San Joaquin Valley. It can apparently withstand considerable drought, since it produced heavy vegetative growth and many seedlings following severe drought in 1983-1985.

United States

Rounded National Status Rank: N2 - Imperiled

Rounded Global Status Rank: G2 - Imperiled

Reasons: Eryngium racemosum is known from fewer than 19 extant sites, only 14 of which contain significant numbers of plants. Most sites have multiple threats. This plant is extremely vulnerable to changes in its habitats hydrologic characteristics. It is unlikely that many more sites will be found. A mega-project, CALFED, may impact several populations; CALFED also may work to restore others. The "Q" is appended to the global rank to indicate that some biologists disagree that Eryngium racemosum is distinct from other, more common species.

Comments: Since much of the fieldwork on known sites was done in the 1980's, current information is lacking on today's land use and threats in the habitat of this plant.

The main threat in the past to Eryngium racemosum has been agricultural conversion of land. The seven sites that were extirpated were all lost to agriculture. Some sites are under the protection of public lands today, but threats are still present. Current threats include heavy grazing, weed invasion, land conversion to other uses, such as duck ponds, channel maintenance, and perhaps most importantly, flood protection and "habitat enhancement" work.

Since annual flooding is so important to the existence of this plant, any alteration in the flood regime would probably be detrimental. The riverine habitat of Eryngium racemosum is located within the center of activity and controversy surrounding the "CALFED" project, an effort to balance all of the diverse water needs of the state for the next 50 years. CALFED will result in many proposals to channelize waterways, as well as in proposals to restore habitat. There could be both good and bad results from CALFED for Eryngium; monitoring of existing sites over the life of CALFED will be critical to evaluate the effects.

Channelization of waterways that Eryngium is associated with is a major threat. This alters the flood regime, changes the physical character of the habitat, and severely disturbs adjacent areas. Evidence suggests that Eryngium will disappear from sites following channelization of streams and rivers.

Restoration of habitat may or may not aid Eryngium racemosum. Restoration would presumably include the de-channelization of rivers and streams and restoration of the natural flood regime. Since this kind of activity is likely to occur as part of CALFED, monitoring of the results will be important.

The invasion of exotic weeds into the habitat of Eryngium racemosum is also a concern. Often, water conditions in communities supporting E. racemosum are such that heavy stands of Helianthus annuus and Xanthium sp. (probably strumarium) are promoted. In these areas, Eryngium is shaded out. This has happened on both the San Luis NWR and the Merced NWR, both protected sites. These weeds may be controlled by a more natural flood regime, which does not favor their growth.

Heavy cattle grazing may also be detrimental to this plant, though reports are unclear as to whether cattle eat and trample the plant to death, or simply promote competing weeds.

Restoration Potential: The restoration potential for Eryngium racemosum is not known, but is suspected to be good, given that its habitat requirements are met. Robert Edminster, one of the experts on this plant, feels that levee setbacks (one of the restoration methods likely during the CALFED program) could impact some populations, but that habitat could also be created this way. Since flooding and leaching of the soil seem to be important to this plant, the levees should not be set too far back or the leaching capability of the river may be diminished. This latter situation could also favor undesirable weeds, such as Helianthus and Xanthium.

Another biologist, Les Howard (CDFG), notes that there are no levees in the plant's "stronghold". This may indicate that levees are changing the hydrological cycle to the detriment of the Eryngium. Howard also believes that grazing benefits the plant since cows control baltic rush, which may be a threat. This author believes that conditions that are good for the rush may not be good for Eryngium, so that what Howard observes may have more to do with the plant's responses to different moisture regimes than to grazing. The use of or control of grazing within Eryngium habitat needs to be researched and monitored.

Preserve Selection and Design Considerations:

GOALS: Preserve design goals should focus on the Eryngium racemosum populations, the associated natural community, and should be clear and concise and have measurable results. For this endangered plant, the first goal should be to bring as many of the highest quality sites as possible under permanent protection through the use of conservation easements or acquisition. The second goal should be to restore damaged sites to a more natural condition.

ECOLOGICAL INFORMATION: The best available ecological and biological information should be used in making decisions. Some key questions remain regarding the ecology of this plant which would be helpful in designing a preserve including: 1. What constitutes a viable population?, 2. What kind of seed bank, if any, does this plant maintain?, 3. What is the role of flooding in the natural ecology of this plant?, and 4. What is the feasibility of creating new habitat for Eryngium?

The answers to the above questions plus information on current threats are essential to designing a comprehensive preserve design strategy. For the immediate future, we should bring more high quality sites under permanent protection. The full set of protected sites should include representation of all of the variation present in the species using parameters such as geographic distribution of the populations, information on morphological and/or genetic variation, and information on habitat differences among the known populations.

CONSERVATION ZONES: Conservation zones should include all processes needed to protect a population over the long-term.

THREATS: Threats must be assessed and updated for each occurrence (see GTHREATCOM section of this ESA). One goal of any site conservation plan is to eliminate as many threats as possible. Management should depend upon the results of research as described under ECOLOGICAL INFORMATION, above. Site design considerations should consider population size and distribution, hydrology, natural and unnatural disturbances, and adjacent land use.

MEASURES OF SUCCESS: A method for the determination of the level of success should be developed in order to evaluate the methods used, to determine if goals and objectives were met, and to determine future directions for conservation actions.

Management Requirements: Management will play a significant role in preventing extinction of Eryngium since we know that populations decline or disappear under certain types of land use such as intensive agriculture, altered flood regime, and possibly under heavy grazing and subsequent weed invasion. Following the successful protection of a population, steps should be taken to evaluate the flood cycle at that site and the most natural regime possible reinstated. Grazing should be ceased or severely curtailed. The local weed populations should be assessed and steps taken to control them, particularly Xanthium and Helianthus. It is possible that simply by establishing a more natural flood cycle the weeds will disappear over time. Competing land uses such as managing for duck clubs, should be evaluated with the long-term viability of the Eryngium in the forefront. Monitoring will be essential in evaluating the success of the management techniques chosen.

Management Programs: Presently, there is no management for Eryngium racemosum. However, it is possible, that under CALFED, that some new sites will be protected and various management strategies applied.

Monitoring Programs: Presently, there is no monitoring program for Eryngium racemosum. The long-term viability of this species will depend on the quality of future monitoring programs and subsequent changes in land management.

Management Research Programs: No current research or management programs exist for this species.

Management Research Needs: Following protection of sites, management strategies should be developed and tested, followed by annual monitoring to evaluate success or failure.

Biological Research Needs: Basic biological and ecological information are needed to design a conservation plan for this species. Research should focus on population dynamics and management strategies to promote long-term viability of populations.

Comments: Individuals knowledgable with this species include: Robert Edminster 1073 Madison Ave. Los Banos, CA 93635

Virginia Goodrow c/o Great Valley Museum Modesto Junior College Modesto, CA 95350

Joe Medeiros c/o Great Valley Museum Modesto Junior College Modesto, CA 95350

Dr. Lincoln Constance Department of Botany University of California Berkeley, CA 94720

Stewardship Overview: Eryngium racemosum grows in seasonally moist habitats such as floodplains on heavy clay soils that are of low pH. The plant requires periodic flooding; this may help to deposit silt and to lower the pH of the soil. It has been speculated that the plant's unique (in the genus) ability to root at the nodes may be associated with the annual silt deposition in its habitat.

There are a total of 27 element occurrences known today. Of these, seven in Stanislaus and San Joaquin counties have been extirpated and one, in Calaveras County, is erroneous. Of the remainder, only 14 sites contain populations with more than 100 plants. Although the plant was historically known from Stanislaus, San Joaquin and Merced counties, the current distribution is primarily located in Merced County. The main threat in the past to Eryngium racemosum has been agricultural conversion of land. The sites that were extirpated were all lost to agriculture. Some sites are under the protection of public lands today, but threats are still present. Current threats include grazing, weed invasion, land conversion to other uses, such as duck ponds, channel maintenance, and perhaps most importantly, flood protection and "habitat enhancement" work.

Since annual flooding is so important to the existence of this plant, any alteration in the flood regime would probably be detrimental. The riverine habitat of Eryngium racemosum is located within the center of activity and controversy surrounding the "CALFED" project, an effort to balance all of the diverse water needs of the state for the next 50 years. CALFED will result in many proposals to channelize waterways, as well as in proposals to restore habitat. There could be both good and bad results from CALFED for Eryngium; monitoring of existing sites over the life of CALFED will be critical to evaluate the effects.

Channelization of waterways that Eryngium is associated with is a major threat. This alters the flood regime, changes the physical character of the habitat, and severely disturbs adjacent areas. Evidence suggests that Eryngium will disappear from sites following channelization of streams and rivers.

Restoration of habitat may or may not aid Eryngium racemosum. Restoration would presumably include the de-channelization of rivers and streams and restoration of the natural flood regime. Since this kind of activity is likely to occur as part of CALFED, monitoring of results will be important.

The invasion of exotic weeds into the habitat of Eryngium racemosum is also a concern. Often, water conditions in communities supporting E. racemosum are such that heavy stands of Helianthus annuus and Xanthium sp. (probably strumarium) are promoted. In these areas, Eryngium is shaded out. This has happened on both the San Luis NWR and the Merced NWR, both protected sites.

Heavy cattle grazing may also be detrimental to this plant, though reports are unclear as to whether cattle eat and trample the plant to death, or simply promote competing weeds.