Plant Assessment Form

Genista monspessulana

Synonyms: Cytisus monpsessulana, C. racemosus, C. canariensis, Gensita monspessulana, Teline monspessulana

Common Names: French broom; soft broom; canary broom; Montepellier broom

Evaluated on: 6/8/04

List committee review date: 11/03/2005

Re-evaluation date:

Evaluator(s)

John J. Knapp/ Invasive Plant Program Manager
Catatlina Island Conservancy
P.O. Box 2739 Avalon, CA 90704
(310) 510-1299
jknapp@catalinaconservancy.org

List commitee members

Joe DiTomaso
John Randall
Carla Bossard

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? High
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes A Reviewed Scientific Publication
Impact?
Four-part score AAAD Total Score
A
1.2 ?Impact on plant community A. Severe Other Published Material
1.3 ?Impact on higher trophic levels A. Severe Other Published Material
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment A. Severe Other Published Material
Invasiveness?
Total Points
18 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 B. Occasional 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 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 Reviewed Scientific Publication
Identify ecosystem processes impacted:

G. monspessulana alters fire regimes by buning readily, increasing fire frequency and intensity (1,2). Alters nutrient and water cycling in Spain (3) and California (4. 5). Dense even aged stands, carries flame to overstory native plants. Nitrogen fixer, increases probability of invasion by other plants.


Sources of information:

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

Out competes native vegetation even on infertile soils (2,4). Displaces native flora (2). Forms dense monostands (1,2,3) that commonly reach 100% cover and extripate populations of native species (3). G. monspessulana grows rapidly (2) and shades out native species (2,3). G. monspessulana grows in close proximity to several listed and endemic plant species and in riparian habitat of listed wildlife species on Catalalina Island (3). Mutualistic relationship with nitrogen-fixing bacteria found in small nodules on roots (2). Fire dervived increase of the root:above-ground biomass ratio allows resprouters to reach higher foliage concentrations, even if nutrient uptake efficiency or soil fertility remain unchanged (4).


Sources of information:

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

Seeds are highly toxic to humans and wildlife (2). Young foliage can cause digestive disorders in horses, and staggering and paralysis in livestock (bison?) (2). Infestations degrade the quality of habitat for wildlife by displacing native forage species and changing microclimate conditions at soil levels, and reduce arthropod populations by 1/3 (as reported in Golden Gate National Recreation Area) (2). Dense thickets can inhibit the movement of wildlife (3), including quail and deer (1).


Sources of information:

Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

No hybridization is known to occur with native California taxa. No native California taxa are in the genus Genista.


Sources of information:

Hickman, J.C. (ed.). 1993. The Jepson manual of higher plants of California. P. 609. University of California Press, Berkeley.


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

Brooms colonize open disturbed sites, roadsides, and pastures, and riparian areas, and can invade undisturbed (2) grasslands, coastal scrub, oak woodlands, and open forests (1). Road construction, pig rooting, fire, and vegetative disturbance facilitate its establishment (2).


Sources of information:

(1) Anonymous. 2001. A comprehensive broom and gorse biological control effort. CalEPPC News 9(2): 3-6.
(2) Anonymous. 2002. Broom: Montpellier broom (Genista monspessulana L.) and English broom (Cytisus scoparius L.). Department of Primary Industries, Water and Environment. http://www.dpiwe.tas.gov.au/inter.nsf/WebPages/RPIO-4ZZ72G?open.


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

Seeds are dispersed explosively up to 3-4 meters from individual plants by shattering (1,2). On Catalina Island, existing populations were surrounded by hundreds of new seedlings, and several young new satelite populations were detected (3). First recorded on Catalina Island in 1967 as infrequent (4), and by 2003 1,915,700 ft2 were invaded (3). Expanded 1.4m/year at Jackson State Demonstration Forest, CA (5).


Sources of information:

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

At least 23 counties are invaded in California, along the coast from Del Norte to San Diego county, and inland in Butte, Yuba, Nevada, Placer, Sacramento and San Bernadino counties (4). Tamalpais State Park in Marin County targeted for removal (1), Catalina Island targeted for removal (2), Jackson Demonstration State Forest tested control methods (3), Golden Gate National Recreation Area targeted for removal (5), Marin County Open Space District preserve- Alto Bowl targeted for removal (5). Broom species including G. monspessulana have been identified as the second most problem weed by Weed Management Area managers (6). Elkhorn Slough National Estuarine Research Reserve- controlled (7). California State Parks- Inland Empire (8). On Santa Catalina Island, 1,915,700 ft2 are invaded (2). Is not spreading as fast as other broom species because has already invaded most potential habitats.


Sources of information:

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

Perennial shrub with deep tap root that reproduces by seed (3), but has been propagated by cuttings (2). Fire stimulates prolific germination (?). Reproductive stage reached by two years (3). Medium sized plants of can produce 8,000 seeds per year and have long-lived seed banks, and become reproductive by 2-3 years (4). Seeds can remain viable in the soil for over 5 years, and plants live between 10-15 years (4,5). Resprouts readily after being cut and sometimes after fire (5). Self-pollination has been successful under experiments (6).


Sources of information:

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

Soil contaminated with seed (1,3), road grading equipment, maintenance machinery, and mud (2,3). Brooms are widely planted as ornamentals (1,4). Vehicles, footwear, pig rooting and the digestive tracts of horses and other animals, and microsites such as: fallen trees and animal tracts facilitate establishment and dispersal (3). Lumber activities are a major cause of spread, as seeds are spread along lumber roads and fall down slopes from clear cuts (5).


Sources of information:

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

Seeds are transported by birds on the Canary Islands (1,3,4), and California quail are suspected of dispersing broom seeds short distances (2). River water also disperse seeds but this species does not grow near water in California (3,4). Seeds do not survive digestion by California quail (5).


Sources of information:

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

Considered naturalized in Australia (1,2,3), and is the most important broom species targeted for biocontrol (4). Also naturalized in New Zealand.


Sources of information:

(1) Blood, K. Date unknown. Environmental Weeds: a field guide for SE Australia.
(2) Harden, G.J. (ed.). 1990. Flora of New South Wales, Vol. 2. New South Wales University Press: Kensington, Australia.
(3) Panetta, F.D., Groves, R.H. and Shepherd, R.C. 1998. The biology of Australian Weeds, Vol. 2. R.G. and F.J. Richardson: Meredith, Australia.
(4) Syrett, P., Fowler, S.V., Coombs, E.M., Hosking, J.R., Markin, G.P., Paynter, Q.E. and Sheppard, A.W. 1999. The potential for biological control of Scotch broom (Cytisus scoparius) (Fabaceae) and related weedy species. Biocontrol News and Information, 20(1):17-33.


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

G. monspessulana was first introduced to California in 1871 and reported naturalized by the 1940's (1,5). On Santa Catalina Island, 85 populations were recorded and the following is the percentage of habitats invaded: bare-<0.00%, coastal scrub-<0.00%, coastal scrub/grassland-1.6%, grassland-0.16%, chaparral-0.02%, riparian-0.08%, and 13 populations wee recorded in non-native communities (2). G. monspessulana invades coastal plains, mountain slopes, grasslands, and open canopy forests, and disturbed places such as: river banks, road cuts, and forest clear cuts (3). G. monspessulana also invades coast live oak (4), valley grassland (6), foothill oak woodland (6).


Sources of information:

(1) Mastro, L.W. 1987. Effects of Dyers Greenwold, Cytisus linifolius (Fabaceae) on the native vegetation of Santa Catalina Island. Crossosoma, 13(6):2-6.
(2) Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished.
(3) Bossard, C.C. 2000. Genista monspessulana. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, (eds). In, Invasive plants of Californias wildlands. Pp. 203-208. Berkeley, California: University of California Press.
(4) Archbald, G. 1994. A French broom control method. CalEPPC News. 2(1): 4-6.
(5) Alexander, J.M. and C.M. DAntonio. 2003. Control methods for the removal of french and scotch broom tested in coastal California. Ecological Restoration 21(3): 191-198.
(6) Schwartz, M.W., Porter, D.J., Randall, J.M. and Lyons, K.E. 1996. Impact of nonindigenous plants. Sierra Nevada Ecosystem Project: Final report to Congress, vol. II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources. Pp.1203-1226.


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

See 3.1.


Sources of information:

(1) Mastro, L.W. 1987. Effects of Dyers Greenwold, Cytisus linifolius (Fabaceae) on the native vegetation of Santa Catalina Island. Crossosoma, 13(6):2-6.
(2) Knapp, J.J. 2004. Catalina Invasive Plant Ranking Plan for the Catalina Island Conservancy. Unpublished.
(3) Bossard, C.C. 2000. Genista monspessulana. Bossard, C.C., J.M. Randall, and M.C. Hoshovsky, (eds). In, Invasive plants of Californias wildlands. Pp. 203-208. Berkeley, California: University of California Press.
(4) Archbald, G. 1994. A French broom control method. CalEPPC News. 2(1): 4-6.
(5) Alexander, J.M. and C.M. DAntonio. 2003. Control methods for the removal of french and scotch broom tested in coastal California. Ecological Restoration 21(3): 191-198.
(6) Schwartz, M.W., Porter, D.J., Randall, J.M. and Lyons, K.E. 1996. Impact of nonindigenous plants. Sierra Nevada Ecosystem Project: Final report to Congress, vol. II, Assessments and scientific basis for management options. Davis: University of California, Centers for Water and Wildland Resources. Pp.1203-1226.
(7) Thorne, R.F. 1967. A flora of Santa Catalina Island, California. Aliso, 6(3):1-77.


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 Yes
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 Yes
Total points: 9
Total unknowns: 0
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
desert
interior
Scrub and Chaparralcoastal bluff scrub
coastal scrubC, 5% - 20%
Sonoran desert scrub
Mojavean desert scrub (incl. Joshua tree woodland)
Great Basin scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparralD, < 5%
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairieD, < 5%
valley and foothill grasslandD, < 5%
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 woodlandD, < 5%
riparian scrub (incl.desert washes)D, < 5%
Woodlandcismontane woodlandD, < 5%
piñon and juniper woodland
Sonoran thorn woodland
Forestbroadleaved upland forestD, < 5%
North Coast coniferous forestC, 5% - 20%
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): C

Infested Jepson Regions

Click here for a map of Jepson regions

  • Cascade Range
  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest
  • Modoc Plateau
  • Sonoran Desert