Plant Assessment Form

Emex spinosa

Synonyms: Rumex spinosus

Common Names: devil's thorn; spiny threecornerjack

Evaluated on: 4/5/05

List committee review date: 08/07/2005

Re-evaluation date:

Evaluator(s)

Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709
510-843-3902
edbrusati@cal-ipc.org
Joseph M. DiTomaso
University of California, Davis
Dept. Plant Sci., Mail Stop 4, Davis, CA 95616
530-754-8715
jmditomaso@ucdavis.edu

List commitee members

Jake Sigg
Peter Warner
Bob Case
John Knapp
Elizabeth Brusati

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? Alert
Documentation? 2 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U
Impact?
Four-part score UBAU Total Score
B
1.2 ?Impact on plant community B. Moderate Anecdotal
1.3 ?Impact on higher trophic levels A. Severe Anecdotal
1.4 ?Impact on genetic integrity U. Unknown Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Anecdotal
Invasiveness?
Total Points
11 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Anecdotal
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
C. Low Other Published Material
2.5 ?Potential for human-caused dispersal B. Moderate Anecdotal
2.6 ? Potential for natural long-distance dispersal C. Rare Observational
2.7 ?Other regions invaded U. Unknown
3.1 ?Ecological amplitude/Range
(see Worksheet C)
D. Narrow Other Published Material
Distribution?
Total Score D
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Anecdotal

Table 3. Documentation

Scores are explained in the "Criteria for Categorizing Invasive Non-Native Plants that Threaten Wildlands".

Section 1: Impact
Question 1.1 Impact on abiotic ecosystem processes? U
Identify ecosystem processes impacted:

Sources of information:

Question 1.2 Impact on plant community composition,
structure, and interactions?
B Anecdotal
Identify type of impact or alteration:

It reduces populations of Lotus nuttallianus. This plant carpets areas if left unchecked, crowding out all other species. Prevalent at Lichty Mesa, in an area with endangered plants.


Sources of information:

Cindy Burrascano, California Native Plant Society, pers. comm. E-mail 2/15/05 in Cal-IPC files


Question 1.3 Impact on higher trophic levels? A Anecdotal
Identify type of impact or alteration:

Sources of information:

1. Jim Peugh, California Native Plant Society, pers. comm.
2. Cindy Burrascano, California Native Plant Society, pers. comm. E-mail 2/15/05 in Cal-IPC files
3. Gregory Gieselman, personal communication. Submission to Cal-IPC Pest Plant form, 1/27/05


Question 1.4 Impact on genetic integrity? U Other Published Material

None No native Emex species in California, but there are native Rumex with the potential for hybridization.


Sources of information:

Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
A Anecdotal
Describe role of disturbance:

Spreads along trails, then moves into undisturbed areas. Without more documentation, not sure whether it establishes in truly undisturbed natural habitats or if it needs at least an open area in order to colonize.


Sources of information:

Cindy Burrascano, California Native Plant Society, pers. comm. E-mail 2/15/05 in Cal-IPC files


Question 2.2 Local rate of spread with no management? A Anecdotal
Describe rate of spread:

Has spread recently in Lichty Mesa near the Mexican border. None in 2003, now prevalent in endangered plant habitat. May have been spread by border control equipment (1). Spreading rapidly in Mission Bay (2).


Sources of information:

Cindy Burrascano, California Native Plant Society, pers. comm. E-mail2/15/05 in Cal-IPC files
2. Gregory Gieselman, personal communication. Submission to Cal-IPC Pest Plant form, 1/27/05


Question 2.3 Recent trend in total area infested within state? B Observational
Describe trend:

Based on entire state it is spreading by not quickly, except in some regions of southern California. Primarily spreading in southern California.


Sources of information:

DiTomaso, observational.


Question 2.4 Innate reproductive potential? C Other Published Material
Describe key reproductive characteristics:

Monoecious annual (1).


Sources of information:

Putievsky, E., P. W. Weiss, and D. R. Marshall. 1980. Interspecific hybridization between Emex australis and E. spinosa. Australian Journal of Botany. 28:323-328
Hickman. 1993. The Jepson Manual.


Question 2.5 Potential for human-caused dispersal? B Anecdotal
Identify dispersal mechanisms:

May be spread by equipment used by border patrol for smoothing dirt. Spreads along trails then moves into undisturbed areas (1). Spiny seed pod sticks to people and anything else it touches (2).


Sources of information:

1. Cindy Burrascano, California Native Plant Society, pers. comm. E-mail 2/15/05 in Cal-IPC files
2. Gregory Gieselman, personal communication. Submission to Cal-IPC Pest Plant form, 1/27/05


Question 2.6 Potential for natural long-distance dispersal? C Observational
Identify dispersal mechanisms:

Spiny seed pods could stick to fur, feathers, or feet, but most seed fall at base of parent plant.


Sources of information:

DiTomaso, observational.


Question 2.7 Other regions invaded? U
Identify other regions:

Native to the Mediterranean area. Invasive in Australia (1). Also present in Texas, Hawaii, New Jersey, and Massachusetts (2). In Hawaii, inhabits open, dry to mesic disturbed areas (3). Mostly in disturbed habitat in other areas. Not enough information to score.


Sources of information:

1. Fromm, G. 1996. Emex species in Australia. Plant Protection Quarterly. 11(4): 146-150
2. USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
3.Hawaiian Ecosystems at Risk. Emex spinosa. Institute of Pacific Islands Forestry. Pacific Island Ecosystems at Risk. Available: http://www.hear.org/pier/species/emex_spinosa.htm


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? D Other Published Material

Present in Orange and San Diego counties (1). A serious problem in San Diego coastal areas (2). Margins of sandy beaches, other coastal habitats?


Sources of information:

1. USDA, NRCS. 2005. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2. Cindy Burrascano, California Native Plant Society, personal communication.
Hickman. 1993. The Jepson Manual.


Question 3.2 Distribution/Peak frequency? D Anecdotal
Describe distribution:

Seems to be present only in the far southern part of the state so far.


Sources of information:

E-mails cited in questions above.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Yes
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually No
Seeds remain viable in soil for three or more years Unknown
Viable seed produced with both self-pollination and cross-pollination No
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes No
Fragments easily and fragments can become established elsewhere No
Resprouts readily when cut, grazed, or burned No
Total points: 2
Total unknowns: 1
Total score: C?

Related traits:

Worksheet B - Arizona Ecological Types is not included here

Worksheet C - California Ecological Types

(sensu Holland 1986)
Major Ecological Types Minor Ecological Types Code?
Marine Systemsmarine systems
Freshwater and Estuarine lakes, ponds, reservoirs
Aquatic Systemsrivers, streams, canals
estuaries
DunescoastalD, < 5%
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrub
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plain
Bog and Marshbog and fen
marsh and swamp
Riparian and Bottomland habitatriparian forest
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forest
closed cone coniferous forest
lower montane coniferous forest
upper montane coniferous forest
subalpine coniferous forest
Alpine Habitatsalpine boulder and rock field
alpine dwarf scrub
Amplitude (breadth): D
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Sonoran Desert
  • Southwest