Plant Assessment Form

Brassica tournefortii

Common Names: Sahara mustard; Morrocan mustard; Asian mustard

Evaluated on: 2/10/03 and revised 9/15/05

List committee review date: 10/02/2003

Re-evaluation date:

Evaluator(s)

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

List commitee members

Carla Bossard
Joe DiTomaso
John Randall
Peter Warner
Doug Johnson
John Hall
Cindy Roye
Dana Backer

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 2.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes A Observational
Impact?
Four-part score AAUU Total Score
A
1.2 ?Impact on plant community A. Severe Observational
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity U. Unknown
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Other Published Material
Invasiveness?
Total Points
17 Total Score A
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 A. Increasing rapidly Other Published Material
2.4 ?Innate reproductive potential
(see Worksheet A)
A. High Other Published Material
2.5 ?Potential for human-caused dispersal A. High Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare Other Published Material
2.7 ?Other regions invaded B. Invades 1 or 2 ecological types Observational
3.1 ?Ecological amplitude/Range
(see Worksheet C)
A. Widespread Other Published Material
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
C. 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? A Observational
Identify ecosystem processes impacted:

Possible increase in fire frequency and intensity where fire was previously uncommon in desert scrub. Can also increase fuel loads in coastal sage scrub, but mostly replacing other weedy mustards, so not introducing the totally novel fuel as in desert scrub. Increased fuel loads and continuity in interspaces created a new type of fuelbed that may promote fire and change fire regimes


Sources of information:

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

May compete with and reduce biomass, fecundity, and diversity of native annual plants and perennial seedlings. Very high density, cover, and biomass, especially after fire or other major disturbance, indicate that this species uses a lot of soil nutrients (e.g. moisture and minerals). This use very likely reduces nutrient availability for other plants rooted in the upper levels of the soil profile. Native annuals often senesce earlier in the spring where Brassica tournefortii cover is high, compared to where its cover is low.


Sources of information:

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

In coastal sage scrub it may affect T&E species habitat, but mostly replacing other weedy mustards, so not introducing a novel habitat component. In desert scrub may have a greater effect, by competing with and reducing biomass of native annuals that the desert tortoise may depend on to maintain physiological health. Affects on native plant communities may alter habitat quality for higher tropic level species.


Sources of information:

Matt Brooks, personal observations; Jennings, W.B. 1993. Foraging ecology of the desert tortoise (Gopherus agassizii) in the western Mojave Desert. M.S. Thesis. University of Texas at Arlington.; Nagy, K.A., Henen, B.T., Vyas, D.B. 1998. Nutritional quality of native and introduced food plants of wild desert tortoises. Herpetologica 42: 260-267.


Question 1.4 Impact on genetic integrity? U

Unknown, could affect native mustards, possibly making weedy natives more invasive May hybridize with other mutards


Sources of information:

none


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

Can establish in washes or in young sandy soils, may establish in undisturbed coppice mounds beneath desert shrubs where soil nutrients are higher than interspaces, also grows well on road berms, and in areas disturbed by fire and agricultural cropping


Sources of information:

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

Can spread rapidly along roadsides, and out from roadsides along washes in the Mojave and Sonoran deserts Has spread rapidly along roads from the Sonoran Desert into the Mojave Desert during the 1980s and 1990s.


Sources of information:

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

Spreading rapidly in arid and semi-arid shrublands Has spread rapidly along roads from the Sonoran Desert into the Mojave Desert during the 1980s and 1990s.


Sources of information:

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

Sources of information:

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

Contamination of hay, dispersal via vehicle tires Thrives in alfalfa fields, when wet seeds are sticky and can adhere to vehicle tires, particularly significant since it likes to grow in the disturbed soils of roadsides and washes which are frequented by off-road vehicles


Sources of information:

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

Sources of information:

Question 2.7 Other regions invaded? B Observational
Identify other regions:

Currently in dunes and scrub habitats. Could invade grasslands where grass cover is low, has been observed along roadsides at the ecotone between desert scrub and grasslands biomes in southern California


Sources of information:

Matt Brooks, personal observations


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

Desert dunes, coastal bluff scrub, coastal scrub, sonoran desert scrub, mojavean desert scrub, chenopod scrub, upper sonoran scrub all but two scrub minor types


Sources of information:

Matt Brooks, unpublished data and personal observations; Minnich, R. and Sanders A. 2000. Brassica tournefortii. In, Invasive Plants of Californias Widlands. Eds. C. Bossard, J. Randall, and M. Hoshovsky. U.C. Press, Berkeley


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

In desert scrub systems it is typically found along roadsides and in washes, on rare occasions it may spread up hillsides, especially in the sonoran desert where it has been present the longest. In coastal scrub habitats it is commonly found in disturbed areas, especially postfire.


Sources of information:

Matt Brooks, personal observations; Minnich, R. and Sanders A. 2000. Brassica tournefortii. In, Invasive Plants of Californias Widlands. Eds. C. Bossard, J. Randall, and M. Hoshovsky. U.C. Press, Berkeley


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 Yes
Viable seed produced with both self-pollination and cross-pollination Yes
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 Unknown
Total points: 7
Total unknowns: 1
Total score: A?

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
desertC, 5% - 20%
interior
Scrub and Chaparralcoastal bluff scrubC, 5% - 20%
coastal scrubC, 5% - 20%
Sonoran desert scrubC, 5% - 20%
Mojavean desert scrub (incl. Joshua tree woodland)C, 5% - 20%
Great Basin scrub
chenopod scrubC, 5% - 20%
montane dwarf scrub
Upper Sonoran subshrub scrubC, 5% - 20%
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): B
Distribution (highest score): C

Infested Jepson Regions

Click here for a map of Jepson regions

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