Plant Assessment Form

Sisymbrium irio

Common Names: London rocket

Evaluated on: 3/10/04

List committee review date: 19/03/2004

Re-evaluation date:

Evaluator(s)

Matt Brooks/Reearch Botanist
U.S. Geological Survey
160 N.Stephanie St., Henderson, NV 89074
702-564-4615
matt_brooks@usgs.gov

List commitee members

Cynthia Roye
Carla Bossard
Doug Johnson
Joe DiTomaso
Jake Sigg
Alison Stanton
Matt Brooks
Peter Warner.

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 2 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes C Observational
Impact?
Four-part score CBUD Total Score
B
1.2 ?Impact on plant community B. Moderate Observational
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Observational
Invasiveness?
Total Points
10 Total Score C
2.2 ?Local rate of spread with no management C. Stable Observational
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 Observational
2.5 ?Potential for human-caused dispersal B. Moderate Observational
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)
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? C Observational
Identify ecosystem processes impacted:

C. Possibly fire regimes May increase fuel loads, but only where alien annual grasses have already altered the fire regime, so additional effect of this species may be only to slightly increase fire intensity.


Sources of information:

Matt Brooks personal observation


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

B. May reduce biomass and fecundity of co-existing species. Can produce large amounts of biomass, and matures early in the phenologic year, possibly usurping soil water before other native annual plants reach peak development


Sources of information:

Matt Brooks personal observation


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

U: Unknown There is some indication that chemicals in mustards eaten by the Desert Tortoise (Gopherus agassizii) may have negative physiological effect, but this is only conjecture at this point.


Sources of information:

Kristin Berry, personal communication


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

D. no known hybridiation There are no native Sisymbrium species in California.


Sources of information:

The Jepson Manual, Higher Plant of Calfifornia. U.C. Press. and Matt Brooks personal observation


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

B. Disturbance promotes dominance and spread.


Sources of information:

Matt Brooks personal observation


Question 2.2 Local rate of spread with no management? C Observational
Describe rate of spread:

C. Slow unless there is disturbance.


Sources of information:

Matt Brooks personal observation


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

B. slightly increasing


Sources of information:

Matt Brooks and Joe DiTomaso personal observation


Question 2.4 Innate reproductive potential? B Observational
Describe key reproductive characteristics:

B. Moderate


Sources of information:

Matt Brooks personal observation


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

B. Moderate


Sources of information:

Matt Brooks personal observation


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

C. Low


Sources of information:

Matt Brooks personal observation


Question 2.7 Other regions invaded? U
Identify other regions:

U. unknown


Sources of information:

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

A. Widspread


Sources of information:

Hickman, 1993. The Jepson Manual, Higher Plant of Calfifornia. U.C. Press. and Matt Brooks personal observation, DiTomaso, J.M. and E.A. Healy. Weeds of California and other Western States. University of California, Division of Agriculture and Natural Resources, Oakland, CA (in press, expected publication in 2005).


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

B


Sources of information:

Matt Brooks personal 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 Yes
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 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 No
Total points: 4
Total unknowns: 2
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 scrubC, 5% - 20%
coastal scrubB, 20% - 50%
Sonoran desert scrubD, < 5%
Mojavean desert scrub (incl. Joshua tree woodland)D, < 5%
Great Basin scrubD, < 5%
chenopod scrubD, < 5%
montane dwarf scrub
Upper Sonoran subshrub scrubD, < 5%
chaparralD, < 5%
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieC, 5% - 20%
valley and foothill grassland
Great Basin grassland
vernal poolD, < 5%
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)
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): A
Distribution (highest score): B

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Desert Province
  • Mojave Desert
  • Sonoran Desert
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Sierra Nevada East
  • Southwest