Plant Assessment Form

Olea europaea

Common Names: olive

Evaluated on: 12/23/04

List committee review date: 25/10/2017

Re-evaluation date:

Evaluator(s)

Elizabeth Brusati, project manager
California Invasive Plant Council
1442A Walnut St. #462, Berkeley, CA 94709
510-843-3902
edbrusati@cal-ipc.org

List commitee members

Joe DiTomaso
John Randall
Carla Bossard

General Comments

Re-evaluated 1/10/06 by Joe DiTomaso, John Randall, Peter Warner, Jake Sigg
A major invasive species in Australia, but only two escaped populations in California. A concern because of the potential for spread from orchards.

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 3 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U Reviewed Scientific Publication
Impact?
Four-part score UCDD Total Score
C
1.2 ?Impact on plant community C. Minor Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels D. Negligible Observational
1.4 ?Impact on genetic integrity D. None Reviewed Scientific Publication
2.1 ?Role of anthropogenic and natural disturbance in establishment C. Minor Reviewed Scientific Publication
Invasiveness?
Total Points
11 Total Score B
2.2 ?Local rate of spread with no management B. Increases less rapidly Observational
2.3 ?Recent trend in total area infested within state C. Stable Observational
2.4 ?Innate reproductive potential
(see Worksheet A)
C. Low Reviewed Scientific Publication
2.5 ?Potential for human-caused dispersal A. High Other Published Material
2.6 ? Potential for natural long-distance dispersal C. Rare 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 Other Published Material
Distribution?
Total Score B
3.2 ?Distribution/Peak frequency
(see Worksheet C)
D. Very low 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? U Reviewed Scientific Publication
Identify ecosystem processes impacted:

Unknown


Sources of information:

No information available.


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

In other areas, displaces native species, reduces light availability. However, occurs only in small patches or as single trees in California and does not have any perceived impacts.


Sources of information:

Spennemann, D. H. R., and L. R. Allen. 2000. The avian dispersal of olives Olea europaea: implications for Australia. Emu. 100: 264-273


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

In other areas, fruits commonly eaten and dispersed by birds, but this has not been observed in California.
Dispersed by feral hogs on Santa Cruz Island (3).


Sources of information:

Spennemann, D. H. R., and L. R. Allen. 2000. The avian dispersal of olives Olea europaea: implications for Australia. Emu. 100: 264-273
Rey, P. J., and J. M. Alcantara. 2000. Recruitment dynamics of a fleshy-fruited plant (Olea europaea): connecting patterns of seed dispersal to seedling establishment. Journal of Ecology. 88:622-633

3. Roberts, James. 2005. Personal communication, Cal-IPC Symposium. Proceedings of the 2005 Cal-IPC Symposium. Available: www.cal-ipc.org


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

none no closely-related native species


Sources of information:

Hickman, J. C. (ed.) 1993. The Jepson Manual, Higher Plants of California. University of California Press. Berkeley, CA enter text here


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

Invades disturbed and marginal habitats such as roadsides and riparian strips.

From habitats observed, Olea invades disturbed areas, such as upland areas adjacent to riparian corridors (e.g., Big Chico Creek, Butte Co.) or dry coastal grasslands (e.g., Santa Cruz Island), but can also establish away from any apparent disturbance (e.g., Annadel State Park, Sonoma Co.) (2).


Sources of information:

1. Spenneman and Allen 2000

2. Warner, Peter. 1985-2005. Personal observations in Marin, Sonoma, Mendocino, Butte counties.


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

B or C. Probably spreads slowly as it only produces fruit every other year. Does not appear to be spreading in California despite its rapid spread in Australia.


Sources of information:

Observational- DiTomaso.


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

Not spreading, appears to be stable.


Sources of information:

Observational - DiTomaso


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

Reproduces at 7-8 years in garden, but much later in field. Bears hermaphroditic flowers. Pollen has partial self-compatibility. Fruit produced in cycles of 2-3 years. Seeds are dormant for 20 months and are vulnerable to rodent herbivory during that time. Seedling survival is critical link in regeneration. In Spain, water stress was responsible for 70% of seedling losses (2).
Can produce fruit on one-year-old shoots in presence of sunlight (2).


Sources of information:

Rey, P. J. and J. M. Alcantara 2000. Recruitment dynamics of a fleshy-fruited plant (Olea europaea): Connecting patterns of seed dispersal to seedling establishment. Journal of Ecology 88(4): 622-633
Thomas, J. 1995. Olive fact sheet. University of California Fruit and Nut Research and Information Center. http://fruitsandnuts.ucdavis.edu/crops/olive_factsheet.shtml. Accessed 12/23/04


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

Escapes from olive groves (1). Could escape from gardens via avian dispersal, although there are fruitless cultivars (2).
Still widely sold as an ornamental as well as a crop plant. Very common in urban areas.


Sources of information:

Found in Cal-IPC nursery survey 2004
1. Spennemann and Allen 2000
2. University of Arizona Pima County Cooperative Extensions, Master Gardeners. Olea europaea. http://ag.arizona.edu/pima/gardening/aridplants/olea_europaea.html


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

Commonly dispersed by birds, including species such as starlings, crows, and sparrows, that are present in California (1,2). Recruitment under conspecifics is nearly zero, so avian dispersal is important (1). Probably do not often disperse it beyond 1 km.


Sources of information:

1. Rey and Alcantara 2000, 2. Spenneman and Allen 2000


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

Introduced around Mediterranean and to Australia for cultivation of olive oil, also in South Africa and Hawaii. Seems to be in at least one other habitat type in Australia.


Sources of information:

Spennemann and Allen 2000
USDA PLANTS database. http://plants.usda.gov. Accessed online 12/23/04


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

Prefers Mediterranean climate with cool, but not too frosty, winter, and long, hot growing season (1). Present in California grasslands, riparian areas,and oak woodland (2). Brought to CA by missionaries in 1700's, increased plantings 1870-1900 (3).


Sources of information:

1. Spenneman and Allen 2000
2. Meyers-Rice B., Randall J. _—“Weed Report: Olea europaea Russian Olive._— The Nature Conservancy Wildland Weeds Management and Research 1998-99 Weed Survey.
3. Thomas, J. 1995. Olive fact sheet. University of California Fruit and Nut Research and Information Center. http://fruitsandnuts.ucdavis.edu/crops/olive_factsheet.shtml. Accessed 12/23/04


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

Only infrequently to rarely encountered as a wildland weed in California.


Sources of information:

Observational- DiTomaso


Worksheet A - Innate reproductive potential

Reaches reproductive maturity in 2 years or less No
Dense infestations produce >1,000 viable seed per square meter No
Populations of this species produce seeds every year. No
Seed production sustained over 3 or more months within a population annually Unknown
Seeds remain viable in soil for three or more years No
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: 2
Total unknowns: 1
Total score: C?

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 scrub
chenopod scrub
montane dwarf scrub
Upper Sonoran subshrub scrub
chaparral
Grasslands, Vernal Pools, Meadows, and other Herb Communitiescoastal prairie
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 forestD, < 5%
riparian woodland
riparian scrub (incl.desert washes)
Woodlandcismontane woodlandD, < 5%
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): D

Infested Jepson Regions

Click here for a map of Jepson regions

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