Plant Assessment Form

Eichhornia crassipes

Synonyms: Eichhornia speciosa, Heteranthera formosa, Piaropus crassipes, Pontederia crassipes

Common Names: water hyacinth

Evaluated on: 8/20/04

List committee review date: 27/08/2004

Re-evaluation date:

Evaluator(s)

Brianna Richardson, Project Manager
California Invasive Plant Council
1442-A Walnut Street #462, Berkeley, CA 94709
510.843.3902
brichardson@cal-ipc.org

List commitee members

Alison Stanton
Cynthia Roye
Jake Sigg
John Randall
Joe DiTomaso
Peter Warner

General Comments

Water hyacinth has both economically beneficial uses and causes significant economic damage, neither of which is considered in this assessment.

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 Reviewed Scientific Publication
1.3 ?Impact on higher trophic levels A. Severe Reviewed Scientific Publication
1.4 ?Impact on genetic integrity D. None Other Published Material
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 C. Stable 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 C. Already invaded 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 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:

Forms dense mats that block sunlight. Mats clog waterways, and alter water oxygen levels, temperature, and pH. Increases suspended and dissolved organic matter, nitrogen, and phosphorous. Decreases nitrate nitrogen. Increases sulphate content. Increases biological oxygen demand and chemical oxygen demand. Removes pollutants from water. Increases water losses from lakes and rivers due to its high traspiration rate (almost 8x that of evaporation from open water). Increases carbon-dioxide tension and turbidity. Adds suspended particulate matter to water. Lowers water temperature. Increases free carbon-dioxide, and decreases dissolved oxygen. Increases calcium hardness. Increases water conductivity. Decreases water transparency. Changes chemistry, light availability, water temperature, and water evaporation rates of infested waterways.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Aneja, KR, K Singh. 1992. Effect of waterhyacinth (Eichhornia crassipes) on the physico-chemical environment of a shallow pond. Proceeding of the Indian National Science Academy. B58(6): 357-364.
Rommens, W., J Maes, N Dekeza, P Inghelbrecht, T Nhiwatiwa, E Holsters, F Ollevier, B Marshall, L Brendock. 2003. The impact of water hyacinth (Eichhornia crassipes) in a eutrophic subtropical impoundment (Lake Chivero, Zimbabwe). I. Water quality. Archive Fuer Hydrobiologie. 158(3): 373-388.


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

Forms dense mats that produce a large amount of dry matter. Displace native aquatic vegetation. Causes extreme hypoxic and hypercarbic conditions harmful to native plants. In the Brendock et. al. study, hyacinth decreased planktonic and macrophyte diveristy, while blue-green algae abundance increased. Can provide shelter for snakes in some areas. On Lake Okeechobee (in FL) hyacinth was allowed to grow in 1986 and between Aug and Nov had "destroyed native plant communities." On Lake Okeechobee (in FL) hyacinth was allowed to grow in 1986 and between Aug and Nov had "destroyed native plant communities." Forms large, dense monocultures. Occludes water surface. Decreases aquatic plant diversity and abundance. Creates increased structural layer (in canopy).


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Aneja, KR, K Singh. 1992. Effect of waterhyacinth (Eichhornia crassipes) on the physico-chemical environment of a shallow pond. Proceeding of the Indian National Science Academy. B58(6): 357-364.
Brendonck, L, J Maes, W Rommens, N Dekeza, T Nhiwatiwa, M Barson, V Callebaut, C Phiri, K Moreau, B Gratwicke, M Stevens, N Alyn, E Holsters, F Ollevier, B Marshall. 2003. The impact of water hyacinth (Eichhornia crassipes) in a eutrophic subtropical impoundment (Lake Chivero, Zimbabwe). II. Species diversity. Archive Fuer Hydrobiologie. 158(3): 389-405.
Parsons, WT, EG Cuthbertson. 1992. Noxious Weeds of Australia. Inkata Press, Melbourne. P. 139-144.
Joyce, JC. 1992. Impac of Eichhornia and Hydrilla in the United States. ICES Marine Science Symposium: 106-109.
Observational, Joe DiTomaso, John Randall, 2004.


Question 1.3 Impact on higher trophic levels? A Reviewed Scientific Publication
Identify type of impact or alteration:

Provides mosquito habitat. Displace native wildlife. European honey bee main pollinator in CA. Degrades water fowl habitat by reducing open water. When decomposing, makes water unfit for consumption by wildlife. Displaces native plants used as food and shelter by wildlife. Changes to water chemistry and light levels affect the health of fish. Causes extreme hypoxic and hypercarbic conditions harmful to wildlife. In the Brendock et. al. study, hyacinth decreased planktonic and macrophyte diversity, while increasing macro-invertabrate and fish diversity in some areas. Can provide shelter for snakes in some areas. Reduces water, shelter, and food sources for wildlife. Can negatively impact migratory birds. Decreases planktonic diversity. Can increase fish diversity (one study). Can provide shelter for some animals. The negative effects on wildlife appear to outweigh any benefits some species may accrue.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Aneja, KR, K Singh. 1992. Effect of waterhyacinth (Eichhornia crassipes) on the physico-chemical environment of a shallow pond. Proceeding of the Indian National Science Academy. B58(6): 357-364.
Brendonck, L, J Maes, W Rommens, N Dekeza, T Nhiwatiwa, M Barson, V Callebaut, C Phiri, K Moreau, B Gratwicke, M Stevens, N Alyn, E Holsters, F Ollevier, B Marshall. 2003. The impact of water hyacinth (Eichhornia crassipes) in a eutrophic subtropical impoundment (Lake Chivero, Zimbabwe). II. Species diversity. Archive Fuer Hydrobiologie. 158(3): 389-405.


Question 1.4 Impact on genetic integrity? D Other Published Material

There are no closely related CA natives.


Sources of information:

Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.


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

Dams can create still water conducive to establishment. Disturbance is unneccesary for establishment.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Parsons, WT, EG Cuthbertson. 1992. Noxious Weeds of Australia. Inkata Press, Melbourne. P. 139-144.


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

Extremely high rate of growth. Plant numbers can double in ~5 days. One plant can cover 600 square meters in one year. Without management, hyacinth can easily double in less than 10 years.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.


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

Populations have declined in LA and other SE states, but the agents have not become established in CA.


Sources of information:

Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Personal knowledge, Joe DiTomaso. 2004.


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

Flowers June-October. Plants linked by stolons from stem. Insect pollinated. Each seed capsule can contain up to 300 seeds. Stems can survive foliage death (by frost) and grow new foliage. Reproduces vegetatively from stolons and by seed. In temperate regions, seeds may survive up to 20 yrs in dried mud, survive for several years in sediment. Fragments as small as 1.5 cm and rhizomes can establish new plants. Believed to be self-pollinated. Bunches of plants break off and float to establish elsewhere. A single plant can produce new infestations. Reaches reproductive maturity within a few weeks. 11 points.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Forno, IW, AD Wright. 1993. The biology of Australian weeds. 5. Eichhornia crassipes. The Jouranl of the Australian Insitute of Agricultural Science (v/n unknown): 21-28.


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

Vegetative parts and seed dispersed by human activity. Actively transported by people both for ornamental establishment in natural waterways and by dumping. Used as a packing material and as cushions in boats. Sold horticulturally for water gardens. Increasingly used for sewage treatment in the US. Vegetative fragments can be carried by boats from one place to another. Most dispersal is human caused. Sold horticulturally. Many opportunities for both intentional and accidental dispersal by humans.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Parsons, WT, EG Cuthbertson. 1992. Noxious Weeds of Australia. Inkata Press, Melbourne. P. 139-144.


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

Vegetative parts and seed dispersed along waterways. Seeds can cling to the feet and feathers of birds. Migratory birds may be an important mechanism. Frequent long-distance dispersal by the flow of waterways. Occassional long-distance dispersal by birds.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.


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

Occurs almost worldwide in tropical and warm temperate regions. AZ, southern and eastern US. Dominates waterways in 50 countries. Invades many other places, but is restricted to the same habitat already invaded in CA.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Parsons, WT, EG Cuthbertson. 1992. Noxious Weeds of Australia. Inkata Press, Melbourne. P. 139-144.


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

Introduced from Brazil in 1884 as an ornamental. First found in CA in 1904. Ponds, sloughs, channels, streams, lakes, other still or slow-moving water. Invades only one major and two minor ecological types in CA.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.


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

Central Valley, San Francisco Bay region, South Coast, Peninsular Ranges. Sacramento-San Joaquin Delta heavily infested. Exists in less than 5% of freshwater systems in CA.


Sources of information:

DiTomaso, JM, EA Healy. 2003. Aquatic and Riparian Weeds of the West. University of California Agriculture and Natural Resources publication 3421.
Godfrey, K. 2000. Eichhornia crassipes. In: Invasive Plants of California's Wildlands. Bossard, CC., JM Randall, MC Hoshovsky (eds.) University of California Press, Berkeley: 171-175.
Observational, Joe DiTomaso, John Randall, 2004.


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 Yes
Fragments easily and fragments can become established elsewhere Yes
Resprouts readily when cut, grazed, or burned Yes
Total points: 11
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, 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

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