Plant Assessment Form

Ageratina adenophora

Synonyms: Eupatorium adenophorum, E. glandulosum, E. pasadense.

Common Names: eupatory, croftonweed, thoroughwort, sticky snakeroot, catweed, hemp agrimony, sticky agrimony, sticky eupatorium

Evaluated on: 8/26/03

List committee review date: 04/09/2003

Re-evaluation date:

Evaluator(s)

Cynthia L. Roye, Associate State Park Resource Ecologist
California State Parks
P.O. Box 942896, Sacramento, CA 94296-0001
(916) 653-9083
croye@parks.ca.gov

List commitee members

Matt Brooks
Peter Warner
Joe DiTomaso
Doug Johnson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? No Alert
Documentation? 3.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U No Information
Impact?
Four-part score UBBU Total Score
B
1.2 ?Impact on plant community B. Moderate Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels B. Moderate Reviewed Scientific Publication
1.4 ?Impact on genetic integrity U. Unknown Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Reviewed Scientific Publication
Invasiveness?
Total Points
15 Total Score B
2.2 ?Local rate of spread with no management B. Increases less rapidly Reviewed Scientific Publication
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal B. Moderate Reviewed Scientific Publication
2.6 ? Potential for natural long-distance dispersal B. Occasional Reviewed Scientific Publication
2.7 ?Other regions invaded B. Invades 1 or 2 ecological types Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Reviewed Scientific Publication
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low Other Published Material

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 No Information
Identify ecosystem processes impacted:

Sources of information:

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

Often replaces desirable species, either in agriculrural fields or in native vegetation. Grows rapidly and produces many shoots and branches which form dense thickets.
Rationale: Is a serious agricultural weed , especially in rangeland. In Australia following ten years of drought and overgrazing the plant spread so quickly overrunning dairy land and horticultural land that farmers abandoned their holdings. Release of inhibitors, perhaps allelopathic compounds, into the soil Authors did not state specific source for this information.


Sources of information:

Lichti and Hoshovsky IN: Bossard et al. 2000.


Question 1.3 Impact on higher trophic levels? B Reviewed Scientific Publication
Identify type of impact or alteration:

Fatally toxic to horses causing acute edema of lungs and hemorrhaging. Unpalatable to cattle. Effect on native fauna unknown.
Rationale: Although no references to the effects on native fauna were found, the dire effect on horses has led me to infer that the effect on native fauna could be serious if the plant is consumed. It is eaten by sheep and goats without ill effect if other pasture is available.


Sources of information:

Lichti and Hoshovsky IN: Bossard et al. 2000; Parsons and Cuthbertson. 1992. Noxious Weeds of Australia. Inkata Press, Melbourne and Sidney, AU. 692 pp.


Question 1.4 Impact on genetic integrity? U Reviewed Scientific Publication

Unknown, but there are three closely-related California plants: A. herbacea, A. occidentalis, A. shastensis, so it could have an effect.
Rationale: Likelihood of genetic impact unknown, but possible


Sources of information:

Lichti and Hoshovsky IN: Bossard et al. 2000.


Section 2: Invasiveness
Question 2.1 Role of anthropogenic and natural disturbance
in establishment?
B Reviewed Scientific Publication
Describe role of disturbance:

Occurs in creek beds, on forest clearings and on slopes greater of than 20%. Naturalizes near areas where it has been cultivated.
Rationale: Requires light to germinate so unshaded conditions, such as disturbed areas, are nesessary for establishment. Once established, however, seedlings can withstand considerable shading by compensating for reduced light by increasing leaf area. Deep shade will kill seedlings.


Sources of information:

Lichti and Hoshovsky IN: Bossard et al. 2000. Parsons and Cuthbertson. 1992. Noxious Weeds of Australia.


Question 2.2 Local rate of spread with no management? B Reviewed Scientific Publication
Describe rate of spread:

No hard data in California, in Australia spread very rapidly following drought, overgrazing where it had previousdly spread slowly.
Rationale: May spread quickly under cerain environmental conditions.


Sources of information:

Lichti and Hoshovsky IN: Bossard et al. 2000; Peter Warner, observational.


Question 2.3 Recent trend in total area infested within state? B Other Published Material
Describe trend:

Scattered occurrence records from Alameda County south to Los Angeles County and even inland to San Bernardino County. Only reported from 8 California State Park units between Mt. Tamalpais and Topanga SP.
Rationale: This is an enference; many more occurrences would be expected over the 68 years since the first recorded escape if the increase were more rapid.


Sources of information:

Jepson Treatment and SMASCH County records as accessed over the Internet at:http://ucjeps.berkeley.edu/cgi-bin/JM_map.pl?taxon=AGERATINA%20adenophora&hcode
California State Parks 2002. Resource Contition Assessment


Question 2.4 Innate reproductive potential? A Reviewed Scientific Publication
Describe key reproductive characteristics:

Sets seeds apomictically; 7,000-10,000 seeds per plant per year; 15 to 30 % not viable; seeds mature and are shed April to mid-June; pappus allows easy dispersed by wind and water, buried seeds lose viability at rate of 20%/yr. but plant still spreads because of high seed prod


Sources of information:

Parsons & Cuthbertson 1992. Noxious Weeds of Australia. Inkata Press, Melbourne and Sidney, Australia. 692 pp.


Question 2.5 Potential for human-caused dispersal? B Reviewed Scientific Publication
Identify dispersal mechanisms:

Originally planted horticulturally. Agricultural contaminant, sand and gravel for road construction, agricultural equipment and other vehicles, livestock


Sources of information:

Lishti and Hoshovsky IN: Bossard et al. 2000.


Question 2.6 Potential for natural long-distance dispersal? B Reviewed Scientific Publication
Identify dispersal mechanisms:

seed has a pappus and can be dispersed by wind or water. Did not find data on actual dispersal distance.


Sources of information:

Parsons and Cuthbertson. 1992.


Question 2.7 Other regions invaded? B Other Published Material
Identify other regions:

In New Zealand, is also found on coastal dunes. In Australia, widespread on rangeland. Is found primarily below 1,000 ft elevation in California but up to nearly 6,600 feet in northeast India.


Sources of information:

Holland, Wendy. 1997. A study of Environmental Weeds found on the coastal fringe of Bream Head and in private gardens at Ocean Beach and Urquharts Bay as accessed on the Internet at:http//www/igrin.co.nz/trisha/Breamhead.html


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? A Reviewed Scientific Publication

Date of introduction to California unknown, but in 1935 was reported as a "rare escape" in the San Francisco Bay area and along the south coast. Has been reported in 8 units of the California State Park System from the Angeles District, the Santa Cruz District, the Monterey District and the Marin District. Is in three major ecological types and five minor types in California, so Score is A.
Rationale: Has been reported in 8 units of the California State Park System from the Angeles District to the Marin District.


Sources of information:

Lichti and Hoshovsky IN: Bossard etr al. 2000; California State Parks 2002. Natural Resources Condition Assessment; Roye and Boyd, 2001, Personal Observation of "throughwort" at Mt. Tamalpais SP.


Question 3.2 Distribution/Peak frequency? D Other Published Material
Describe distribution:

Is does not constitute more than 5% of any of the types where it is currently known.-
Rationale: I did not find actual data, but my reasoning is that if it were more common it would have also been reported in the Channel Coast and San Luis Obispo Coast Districts at more units of the California State Park System between those endpoints.


Sources of information:

California State Parks 2002. Natural Resources Condition Assessment; Roye and Boyd, 2001, Personal Observation of "throughwort" at Mt. Tamalpais SP.


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less Unknown
Dense infestations produce >1,000 viable seed per square meter Yes
Populations of this species produce seeds every year. Yes
Seed production sustained over 3 or more months within a population annually Yes
Seeds remain viable in soil for three or more years Yes
Viable seed produced with both self-pollination and cross-pollination No
Has quickly spreading vegetative structures (rhizomes, roots, etc.) that may root at nodes Yes
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 10
Total unknowns: 1
Total score: A?

Related traits:

Sets seeds apomictically; 7,000-10,000 seeds per plant per year; 15 to 30 % not viable; seeds mature and are shed April to mid-June; pappus allows easy dispersed by wind and water, buried seeds lose viability at rate of 20%/yr. but plant still spreads because of high seed prod. Parsons & Cuthbertson.

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
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubD, < 5%
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 forestD, < 5%
riparian woodlandD, < 5%
riparian scrub (incl.desert washes)D, < 5%
Woodlandcismontane woodland
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forest
North Coast coniferous forestD, < 5%
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): B
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Southwest