Plant Assessment Form

Zantedeschia aethiopica

Common Names: calla lily; arum lily

Evaluated on: 7/31/03

List committee review date: 01/08/2003

Re-evaluation date:

Evaluator(s)

Peter J. Warner
California Dept. of Parks and Recreation; CalEPPC
P. O. Box 603, Little River, CA 95456-0603
(707) 937-9172; (707) 937-2278
pwarner@mcn.org

List commitee members

Jake Sigg
Peter Warner
Joe DiTomaso
Doug Johnson
Brianna Richardson

General Comments

No general comments for this species

Table 2. Criteria, Section, and Overall Scores

Overall Score? Limited
Alert Status? No Alert
Documentation? 2.5 out of 5
Score Documentation
1.1 ?Impact on abiotic ecosystem processes U Reviewed Scientific Publication
Impact?
Four-part score UCUD Total Score
C
1.2 ?Impact on plant community C. Minor Observational
1.3 ?Impact on higher trophic levels U. Unknown
1.4 ?Impact on genetic integrity D. None Other Published Material
2.1 ?Role of anthropogenic and natural disturbance in establishment B. Moderate Observational
Invasiveness?
Total Points
16 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 B. Increasing less rapidly Observational
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 B. Invades 1 or 2 ecological types Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
B. Moderate Observational
Distribution?
Total Score C
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:

possibly water availability inference from the species invasiveness in wetlands


Sources of information:

Randall, RP, and SG Lloyd. 2003. Weed warning from downunder. CalEPPC News 11 (1) 4-6.;
Peter Warner (personal observations)


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

displaces native wetland species observations


Sources of information:

Peter Warner


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

probable toxicity to vertebrates inferred from human toxicity from oxalate crystals


Sources of information:

Russell, AB, JW Hardin, L Grand, and A Fraser. 1997. Poisonous Plants of North Carolina. On-line reference at http://www.ces.ncsu.edu/depts/hort/consumer/poison/Zanteae.htm


Question 1.4 Impact on genetic integrity? D Other Published Material

none known; no native species closely related inferred from available phylogenetic information


Sources of information:

Hickman, JC, et al. 1993. The Jepson Manual: Higher Vascular Plants of California


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

little or no apparent human-caused disturbance needed observational _ sites invaded not clearly disturbed; may invade in wetlands with altered nutrient regimes, pH levels, etc.


Sources of information:

Peter Warner (personal observations)


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

appears to be increasing, invading into additional wetland habitats at a moderate rate general observation


Sources of information:

Peter Warner


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

estimated to be slowly increasing in range and sites invaded; many suitable habitats remain uninfested personal observations; CLIMATE computer-modelling program


Sources of information:

Peter Warner (personal observations);
Randall, RP, and SG Lloyd. 2003. Weed warning from downunder. CalEPPC News 11 (1) 4-6


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

Pacific Island Ecosystems at Risk website (http://www.hear.org/pier/zaaet.htm); Peter Warner (personal observations)


Sources of information:

widely sold, propagated, and cultivated commercially; rhizomes dispersed by dumping of garden waste most available information on this taxon is about its horticultural uses; personal observations


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

widely sold, propagated, and cultivated commercially; rhizomes dispersed by dumping of garden waste most available information on this taxon is about its horticultural uses; personal observations


Sources of information:

numerous horticulturally oriented websites (http://www.geocities.com/RainForest/Vines/7025/calla_lily.html; http://www.mobot.org/gardeninghelp/plantfinder/codea/A475.shtml); Peter Warner (personal observations)


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

seeds dispersed by birds written information; also inferred from observations of new populations or those restricted to one or a few plants, these suggesting that plants originated from seed dispersal and not from rhizomes


Sources of information:

Pacific Island Ecosystems at Risk website (http://www.hear.org/pier/zaaet.htm);
Peter Warner (personal observation)


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

southern Australia wetlands and mesic areas written report


Sources of information:

Randall, RP, and SG Lloyd. 2003. Weed warning from downunder. CalEPPC News 11 (1) 4-6


Section 3: Distribution
Question 3.1 Ecological amplitude/Range? B Observational

invasive in freshwater wetlands written information; observations


Sources of information:

Randall, RP, and SG Lloyd. 2003. Weed warning from downunder. CalEPPC News 11 (1) 4-6
Peter Warner (personal observations)


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

common in north coastal wetlands and seeps, but many such sites not invaded observations


Sources of information:

Peter Warner (personal observations)


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 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 Yes
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 6
Total unknowns: 2
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 scrub
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 prairie
valley and foothill grassland
Great Basin grassland
vernal pool
meadow and seep
alkali playa
pebble plainD, < 5%
Bog and Marshbog and fenD, < 5%
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): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Central West
  • Great Valley
  • Northwest
  • Sierra Nevada
  • Southwest