Plant Assessment Form

Limnobium laevigatum

Common Names: South American spongeplant; West Indian spongeplant

Evaluated on: 5/13/11

List committee review date:

Re-evaluation date:

Evaluator(s)

Elizabeth Brusati, Science Program Manager
Cal-IPC
1442-A Walnut St. #462, Berkeley, CA 94709
510-843-3902
edbrusati@cal-ipc.org
Joseph M. DiTomaso, Specialist in Cooperative Extension
Dept. of Plant Sciences, University of California-Davis
Mail Stop 4, One Shields Ave., Davis CA 95616
530-754-8715
jmditomaso@ucdavis.edu

No list committee members listed

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 Other Published Material
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
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 B. Increasing less 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 A. Frequent Other Published Material
2.7 ?Other regions invaded D. Not known anywhere else Other Published Material
3.1 ?Ecological amplitude/Range
(see Worksheet C)
C. Limited Other Published Material
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? A Other Published Material
Identify ecosystem processes impacted:

Has the capacity to cover large areas of open water. This has occurred in the Kings River near Fresno and also is beginning to occur in the Delta. Can cause significant reduction in dissolved oxygen in water resulting in fish kills.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf

Pat Akers, CDFA, Observational, http://www.cdfa.ca.gov/phpps/ipc/hydrilla/sos/sos_info/sos_info_files/frame.htm


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

Forms solids stands that completely cover water, blocking light to all species in water column.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf

Pat Akers, CDFA, observational, http://www.cdfa.ca.gov/phpps/ipc/hydrilla/sos/sos_info/sos_info_files/frame.htm


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

If covers large areas, could block open water needed by waterfowl and other wildlife as well as cause negative impacts to Delta pumping and irrigation systems. However, has not reached this point yet in California.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


Question 1.4 Impact on genetic integrity? D Reviewed Scientific Publication

No native Limnobium in California.


Sources of information:

Jepson Manual


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 rivers, streams, and the Delta without human disturbance.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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

Expected to spread at a more rapid rate than water hyacinth because it not only reproduces through vegetation propagules, but is also a prolific seed producer.


Sources of information:

. Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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

Spreading rapidly in some river systems in the state, as well as the Delta. Management efforts are keeping it from spreading too quickly, but it still is spreading.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf
Pat Akers, CDFA, observational, http://www.cdfa.ca.gov/phpps/ipc/hydrilla/sos/sos_info/sos_info_files/frame.htm


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

Spreads vegetatively and has abundant seed dispersal. Seeds germinate rapidly to produce extremely small, floating seedlings. A handful can contain 60 seedlings.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf
DiTomaso and Healy. 2003. Aquatic and Riparian Weeds of the West. UC ANR Publ. No. 3421.
Pat Akers, CDFA, observational, http://www.cdfa.ca.gov/phpps/ipc/hydrilla/sos/sos_info/sos_info_files/frame.htm


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

Seedlings can likely be spread as hitchhikers on boats. Sold as an aquarium plant.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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

Small floating seedlings are dispersed by wind, currents, and tidal action. Likely can attach to waterfowl or water hyacinth plants.


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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

Native to central Mexico, South America, and the Caribbean. Not known to escape elsewhere


Sources of information:

USDA-GRIN 2011


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

First found in Redding and Arcata in 2003, San Joaquin River in 2007, and Sacramento-San Joaquin Delta in 2008.
Little is known about growth rates, nutrient requirements or cold tolerance. Small seedlings can withstand frost and mild freezes because protected under the taller aquatic vegetation. Currently under study by USDA.


Sources of information:

Hrusa et al. 2002, Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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

New invader, not yet widespread


Sources of information:

Anderson, L. 2011. Spongeplant: A new aquatic weed threat in the Delta. Cal-IPC News. 19(1):4-5. http://www.cal-ipc.org/resources/news/pdf/Cal-IPC_News_2011Spring.pdf


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 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: 10
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, reservoirsD, < 5%
Aquatic Systemsrivers, streams, canalsD, < 5%
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 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): C
Distribution (highest score): D

Infested Jepson Regions

Click here for a map of Jepson regions

  • Great Valley
  • Northwest