Plant Assessment Form

Isatis tinctoria

Common Names: dyer's woad

Evaluated on: 1-Aug-03

List committee review date: 01/08/2003

Re-evaluation date:

Evaluator(s)

Joe DiTomaso
UC Davis
Weed Science Program, Robbins Hall, Univ. California, Davis CA 95616
530-754-8715
DiTomaso@vegmail.ucdavis.edu

List commitee members

Jake Sigg
Peter Warner
Doug Johnson
Joe DiTomaso
Brianna Richardson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Moderate
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes B Reviewed Scientific Publication
Impact?
Four-part score BABD Total Score
B
1.2 ?Impact on plant community A. Severe Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels B. Moderate Other Published Material
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Other Published Material
Invasiveness?
Total Points
13 Total Score B
2.2 ?Local rate of spread with no management A. Increases rapidly Other Published Material
2.3 ?Recent trend in total area infested within state B. Increasing less rapidly Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
B. Moderate Other Published Material
2.5 ?Potential for human-caused dispersal B. Moderate Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
2.7 ?Other regions invaded C. Already invaded Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Distribution?
Total Score A
3.2 ?Distribution/Peak frequency
(see Worksheet C)
B. Moderate Observational

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? B Reviewed Scientific Publication
Identify ecosystem processes impacted:

Deep root system can reduce water for natives.


Sources of information:

Evans, J.O. 1991. The importance, distribution, and control of Dyers woad (Isatis tinctoria). Pages 287-393. In, Noxious Range Weeds. Westview Press, Boulder, CO. Eds. L.F. James, J.O. Evans, M.H. Ralphs and R.D. Child.; Varga, W. A. and Evans, J. O. 1975. Dyers woad and alfalfa interaction - a double take of a competition study. Proceedings of the Western Society of Weed Science 28:38-39.; Farah, K. O., Tanaka, A. F., and West, N. E. 1988. Autecology and population biology of dyers woad (Isatis tinctoria). Weed Science 36:186-193.


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

Competes with shrubs and browse species, particularly natives. Can dominate plant communities.


Sources of information:

Evans, J.O. 1991. The importance, distribution, and control of Dyers woad (Isatis tinctoria). Pages 287-393. In, Noxious Range Weeds. Westview Press, Boulder, CO. Eds. L.F. James, J.O. Evans, M.H. Ralphs and R.D. Child.; Farah, K. O., Tanaka, A. F., and West, N. E. 1988. Autecology and population biology of dyers woad (Isatis tinctoria). Weed Science 36:186-193.


Question 1.3 Impact on higher trophic levels? B Other Published Material
Identify type of impact or alteration:

Reduces grazing capacity by 38%, but no data on livestock grazing.


Sources of information:

Question 1.4 Impact on genetic integrity? D Other Published Material

Probably none. No other species of Isatis in California.


Sources of information:

DiTomaso, J.M. and E. A. Healy. 2005. Weeds of California. Div. Nat. Agr. Res. Univ. California (in press)


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

Prefers disturbance but can move into undisturbed rangeland and forested areas.


Sources of information:

Question 2.2 Local rate of spread with no management? A Other Published Material
Describe rate of spread:

A population in Montana spread from 2 to 100 acres in 2 years. Spreading on BLM land at average of 14% per year.


Sources of information:

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

Seems to be spreading in northern California, but not at rapid rate.


Sources of information:

DiTomaso, observation


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

Seeds are large and individual plants generally produce 350-500 each.


Sources of information:

Question 2.5 Potential for human-caused dispersal? B Other Published Material
Identify dispersal mechanisms:

Moves long distance by vehicles, feed, bedding, hay and crop contamination.


Sources of information:

Roche, C. 1992. Dyers woad (Isatis tinctoria L.). Pacific Northwest Cooperative Extension Publication 384:2 pp.; Callihan, R.H. 1990. Dyers woad. Biology, distribution and control. Univ. Idaho College of Agric., Current Information Series No. 857. 4 pp.


Question 2.6 Potential for natural long-distance dispersal? C Other Published Material
Identify dispersal mechanisms:

Most seed (95%) fall within 2 feet of parent plant. Some long distance movement in water, but not common.


Sources of information:

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

found throughout the western US. Also grows on six other continents as a weed.


Sources of information:

Evans, J.O. 1991. The importance, distribution, and control of Dyers woad (Isatis tinctoria). Pages 287-393. In, Noxious Range Weeds. Westview Press, Boulder, CO. Eds. L.F. James, J.O. Evans, M.H. Ralphs and R.D. Child.; Varga, W. A. and Evans, J. O. 1975. Dyers woad and alfalfa interaction - a double take of a competition study. Proceedings of the Western Society of Weed Science 28:38-39.


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

Introduced to Utah in 1910 and to Siskiyou county, CA in the early 1900s. Common on rocky soils of the intermountain west.


Sources of information:

McConnell, E.G., J.O. Evans, and S.A. Dewey. 1999. Dyers woad. Pp. 231-237. In, Biology and Management of Noxious Rangeland Weeds. Eds. R.L. Sheley and J.K. Petroff, Oregon State Univ. Press, Corvallis.; Callihan, R.H. 1990. Dyers woad. Biology, distribution and control. Univ. Idaho College of Agric., Current Information Series No. 857. 4 pp.


Question 3.2 Distribution/Peak frequency? B Observational
Describe distribution:

Most widely distributed in the Great Basin of NE California.


Sources of information:

DiTomaso, observation


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 Yes
Viable seed produced with both self-pollination and cross-pollination Unknown
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 Yes
Total points: 5
Total unknowns: 1
Total score: B?

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
Dunescoastal
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrub
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrubC, 5% - 20%
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
valley and foothill grasslandB, 20% - 50%
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 forestC, 5% - 20%
closed cone coniferous forestC, 5% - 20%
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): B

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Northwest
  • Sierra Nevada
  • Modoc Plateau