Pacific Island Ecosystems at Risk (PIER)


Cortaderia jubata


RISK ASSESSMENT RESULTS: High risk, score: 26


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment
 Cortaderia jubata (Common name: Andean pampas grass, jubata grass, pink pampas grass, purple pampas grass) Family - Poaceae Synonym: Gynerium jubatum Answer Score
1.01 Is the species highly domesticated? n 0
1.02 Has the species become naturalized where grown? y  
1.03 Does the species have weedy races? n  
2.01 Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical” 2  
2.02 Quality of climate match data (0-low; 1-intermediate; 2-high)                 see appendix 2 2  
2.03 Broad climate suitability (environmental versatility) y 1
2.04 Native or naturalized in regions with tropical or subtropical climates y 1
2.05 Does the species have a history of repeated introductions outside its natural range?  y=-2 y  
3.01 Naturalized beyond native range         y = 1*multiplier (see Append 2), n= question 2.05 y 2
3.02 Garden/amenity/disturbance weed                              y = 1*multiplier (see Append 2)    
3.03 Agricultural/forestry/horticultural weed                         y = 2*multiplier (see Append 2) y 4
3.04 Environmental weed                                                     y = 2*multiplier (see Append 2) y 4
3.05 Congeneric weed                                                          y = 1*multiplier (see Append 2) y 2
4.01 Produces spines, thorns or burrs y 1
4.02 Allelopathic n 0
4.03 Parasitic n 0
4.04 Unpalatable to grazing animals n -1
4.05 Toxic to animals n 0
4.06 Host for recognized pests and pathogens n 0
4.07 Causes allergies or is otherwise toxic to humans n 0
4.08 Creates a fire hazard in natural ecosystems y 1
4.09 Is a shade tolerant plant at some stage of its life cycle y 1
4.1 Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island) y 1
4.11 Climbing or smothering growth habit n 0
4.12 Forms dense thickets y 1
5.01 Aquatic n 0
5.02 Grass y 1
5.03 Nitrogen fixing woody plant n 0
5.04 Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers) n 0
6.01 Evidence of substantial reproductive failure in native habitat n 0
6.02 Produces viable seed. y 1
6.03 Hybridizes naturally    
6.04 Self-compatible or apomictic y 1
6.05 Requires specialist pollinators n 0
6.06 Reproduction by vegetative fragmentation    
6.07 Minimum generative time (years)                 1 year = 1, 2 or 3 years = 0, 4+ years = -1 1 1
7.01 Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas) y 1
7.02 Propagules dispersed intentionally by people y 1
7.03 Propagules likely to disperse as a produce contaminant y 1
7.04 Propagules adapted to wind dispersal y 1
7.05 Propagules water dispersed y 1
7.06 Propagules bird dispersed n -1
7.07 Propagules dispersed by other animals (externally) y 1
7.08 Propagules survive passage through the gut n -1
8.01 Prolific seed production (>1000/m2) y 1
8.02 Evidence that a persistent propagule bank is formed (>1 yr) n -1
8.03 Well controlled by herbicides y -1
8.04 Tolerates, or benefits from, mutilation, cultivation, or fire y 1
8.05 Effective natural enemies present locally (e.g. introduced biocontrol agents)    
  Total score:   26

Supporting data:

  Notes Reference
1.01 No evidence  
1.02 (1)"In Hawai‘i naturalized in dry to wet zones, from 2000 ft to 7,000 ft. Forms dense monotypic stands in mesic to humid areas with the potential to replace or compete with native species." "A problem species in New Zealand (declared noxious weed). On Hawai‘i noxious weed list."   (2)"It is an aggressive colonizer that competes with native vegetation. It can displace native coastal dune, shrub, and estuarine vegetation, and it slows early forest re-growth on logged lands. ... Andean Pampas/Jubata grass is a threat to the integrity of coastal dune, shrub and estuarine ecosystems."  (3)"Jubatagrass is one of the most invasive nonnative species along sensitive natural coastal sites of California." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.nps.gov/archive/redw/pampas.htm  (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata) Weed Science 52 (4) : 525-530 July 2004
1.03 No evidence  
2.01 (1)"Native range:  South America."  (2)"Cortaderia is native to the Andes Mountains of northern ArgenČtina, Bolivia, Peru, and Ecuador at elevations of 2800 to 3400 m (Costas Lippmann 1977, 1979), where it can form nearly solid stands of several hundred hectares." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf
2.02    
2.03 (1)"However, it has broad habitat requirements and will grow vigorously in nearly any soil, under low or high moisture regimes, in full sun or dense shade."  (2)"It has broad habitat requirements and grows vigorously … '  (3)Hardiness:
USDA Zone 5a: to -28.8░ C (-20░ F)
USDA Zone 5b: to -26.1░ C (-15░ F)
USDA Zone 6a: to -23.3░ C (-10░ F)
USDA Zone 6b: to -20.5░ C (-5░ F)
USDA Zone 7a: to -17.7░ C (0░ F)
USDA Zone 7b: to -14.9░ C (5░ F)
USDA Zone 8a: to -12.2░ C (10░ F)
USDA Zone 8b: to -9.4░ C (15░ F)
USDA Zone 9a: to -6.6░ C (20░ F)
USDA Zone 9b: to -3.8░ C (25░ F)
(1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=  (3)http://davesgarden.com/pf/go/31957/index.html
2.04 (1)"Native range:  South America."  (2)"Cortaderia is native to the Andes Mountains of northern ArgenČtina, Bolivia, Peru, and Ecuador at elevations of 2800 to 3400 m (Costas Lippmann 1977, 1979), where it can form nearly solid stands of several hundred hectares." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf
2.05 Known introduced range: C. jubata is now found in New Zealand, Australia, the United States, and South Africa (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.nps.gov/archive/redw/pampas.htm  (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata) Weed Science 52 (4) : 525-530 July 2004  (4)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
3.01 (1)"In Hawai‘i naturalized in dry to wet zones, from 2000 ft to 7,000 ft. Forms dense monotypic stands in mesic to humid areas with the potential to replace or compete with native species." "A problem species in New Zealand (declared noxious weed). On Hawai‘i noxious weed list."   (2)"It is an aggressive colonizer that competes with native vegetation. It can displace native coastal dune, shrub, and estuarine vegetation, and it slows early forest re-growth on logged lands. ... Andean Pampas/Jubata grass is a threat to the integrity of coastal dune, shrub and estuarine ecosystems."  (3)"Jubatagrass is one of the most invasive nonnative species along sensitive natural coastal sites of California." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.nps.gov/archive/redw/pampas.htm  (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata) Weed Science 52 (4) : 525-530 July 2004
3.02 (1)Habitat/ecology:  Disturbed areas, clearings, sand dunes, roadsides, grasslands, pastures, alpine shrublands. Invades disturbed areas, smothering other plants and preventing regeneration.   (2)"PPC (1998) cites that on roadsides, C. jubata can seriously hamper visibility, while its sharp leaves can cause serious cuts to humans." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm   (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
3.03 "Habitat/ecology:  Disturbed areas, clearings, sand dunes, roadsides, grasslands, pastures, alpine shrublands. Invades disturbed areas, smothering other plants and preventing regeneration." http://www.hear.org/pier/species/cortaderia_jubata.htm
3.04 (1)"In Hawai‘i naturalized in dry to wet zones, from 2000 ft to 7,000 ft. Forms dense monotypic stands in mesic to humid areas with the potential to replace or compete with native species." "A problem species in New Zealand (declared noxious weed). On Hawai‘i noxious weed list."   (2)"It is an aggressive colonizer that competes with native vegetation. It can displace native coastal dune, shrub, and estuarine vegetation, and it slows early forest re-growth on logged lands. ... Andean Pampas/Jubata grass is a threat to the integrity of coastal dune, shrub and estuarine ecosystems."  (3)"Jubatagrass is one of the most invasive nonnative species along sensitive natural coastal sites of California."  (4)It is on the 'State Noxious weed list' of 46 states in the U.S. (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.nps.gov/archive/redw/pampas.htm  (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata) Weed Science 52 (4) : 525-530 July 2004  (4)http://plants.usda.gov/java/profile?symbol=COJU2
3.05 "General impacts
C. selloana can form dense stands that exclude other plants. Its sharp leaves cut skin and can limit recreational use of areas, and it can form dense colonies that can become or increase fire hazards (May et al., UNDATED). Once seedlings become established, it is a substantial threat to the ecological quality of preserves, particularly in coastal and grassland sites due to competition with native plants. Its rapid growth and accumulation of above ground and below ground biomass allow it to acquire light, moisture, and nutrients that would be used by other plants. It can be damaging even at low densities because of the amount of cover it can occupy (Starr et al. 2003). Studies comparing C. selloana with Cortaderia jubata a similar species found that C. selloana is genetically more diverse and could be one of the reasons of its success (Lambrinos, 2001).These results are consistent with the hypothesis that genetic variability enables better utilization of heterogeneous habitats as well as promoting greater competitive abilities. In California, C. selloana inhabits a greater range of environmental conditions expanding into continental climatic zones.
The rapid spread of pampas into exotic forests in New Zealand is a particular problem due to it's competition with pine, fire hazard, reduced accessibility and cost of control (Gadgil et al., 1984). Also the great quantity of fluffy seed has caused problems for kiwifruit growers since it clings to the fruit and causes it to be rejected for exprot (Knowles and Tombleson, 1987)."
http://www.invasivespecies.net/database/species/ecology.asp?si=373&fr=1&sts=sss
4.01 "Plant has spines or sharp edges; use extreme caution when handling." http://davesgarden.com/pf/go/31957/index.html
4.02 No evidence  
4.03 No evidence  
4.04 "It has also been used as a forage plant for cattle in California and New Zealand. " http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf
4.05 No evidence  
4.06 The following six fungi species were listed ot be associated with C. jubata:
Exserticlava vasiformis: New Zealand - 7073
Nigrospora sacchari: New Zealand - 7073
Sporoschisma nigroseptatum: New Zealand - 8554
Fusarium equiseti: New Zealand - 40040
Gibberella intricans: New Zealand - 6224
Gibberella zeae: New Zealand - 6224        [No evidence that the above are economic pests].
 
4.07 No evidence  
4.08 (1)"Buildup of dry material can significantly increase fire hazard."  (2")It is also a fire hazard because of the large amount of dry matter it produces." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
4.09 (1)"However, it has broad habitat requirements and will grow vigorously in nearly any soil, under low or high moisture regimes, in full sun or dense shade."(2)" It cannot survive in the shade of the redwood forest." (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://www.nps.gov/archive/redw/pampas.htm
4.1 (1)"However, it has broad habitat requirements and will grow vigorously in nearly any soil, under low or high moisture regimes, in full sun or dense shade."  (2)Seedlings can germinate and become established in a variety of different soil types, including those derived from serpentine rock.  (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf
4.11 Not a climber.  
4.12 (1)"Cortaderia is native to the Andes Mountains of northern ArgenČtina, Bolivia, Peru, and Ecuador at elevations of 2800 to 3400 m (Costas Lippmann 1977, 1979), where it can form nearly solid stands of several hundred hectares.  It becomes established most easily in wet sandy soil without existing vegetation."  (2)"In Hawai‘i naturalized in dry to wet zones, from 2000 ft to 7,000 ft. Forms dense monotypic stands in mesic to humid areas with the potential to replace or compete with native species." (3)Photos of C.jubata stands on hillsides in California. (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://www.hear.org/pier/species/cortaderia_jubata.htm  (3)http://tncweeds.ucdavis.edu/esadocs/cortjuba.html
5.01    
5.02 A large clump forming perennial grass. Staples, W George and Derral H Herbst. 2005. A Tropical Garden Flora. Bishop Museum Press. Honolulu. Hawaii. Page 744.
5.03 No evidence  
5.04    
6.01 "Cortaderia is native to the Andes Mountains of northern ArgenČtina, Bolivia, Peru, and Ecuador at elevations of 2800 to 3400 m (Costas Lippmann 1977, 1979), where it can form nearly solid stands of several hundred hectares.  It becomes established most easily in wet sandy soil without existing vegetation." http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf 
6.02 (1)"Seedlings can germinate and become established in a variety of different soil types, including those derived from serpentine rock."  (2)"Seeds are produced apomictically, and germination is directly related to seed size. Of the total seeds produced, only 20 to 30% were of ample size to readily germinate when exposed to light and under a temperature range similar to coastal environments." (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata). Weed Science 52 (4) : 525-530 July 2004.
6.03 (1)"Abstract: Species [8] 6 hybrids and 4 backcrosses of Cortaderia [C. araucana, C. jubata, C. rudiuscula, C. selloana, C. fulvida, C. richardii, C. splendens, C. toetoe C. araucana-X-C. selloana, C. richardii -X-C. fulvida, C. richardii-X-C. toetoe, C. richardii-X-C. splendens, C. splendens X-C. toetoe and C. araucana-X- C. toetoe] were investigated for cyanogenesis. Samples of 2 spp., 4 hybrids and 1 backcross were acyanogenic even if emulsin was added. All other samples contained a single cyanogenic glucoside which was identified with triglochinin. Results are discussed in a taxonomic context."  (2)"Over the past 80 years the inflorescences of C. selloana have become more similar to those of C. jubata. The plumes have darkened, the spikelets and awns have shortened and the number of florets has decreased. Hybridization between the two speceis is unlikely, and tha apparent convergence of floral form probably represents an adjustment to changing selective pressures" (1)TJON SIE FAT L CONTRIBUTION TO THE KNOWLEDGE OF CYANOGENESIS IN ANGIOSPERMS PART 11 CYANOGENESIS IN SOME GRASSES PART 4 THE GENUS CORTADERIA Proceedings of the Koninklijke Nederlandse Akademie van Wetenschappen Series C Biological and Medical Sciences 82 (2) : 165-170 1979   (2)Lambrinos, John G. The expansion history of a sexual and asexual species of Cortaderia in California, USA. Journal of Ecology 89 (1) : 88-98 February, 2001
6.04 "Jubatagrass can produce over 100,000 wind-dispersed seeds from a single inflorescence. Seeds are produced apomictically, and germination is directly related to seed size." Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata). Weed Science 52 (4) : 525-530 July 2004
6.05 Probably not - "Some C. jubata populations consist entirely of pistillate (female) plants that form seed without the necessity of pollination (apomixis)." http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
6.06 No evidence of vegetative spread.  
6.07 (1)"Seedlings can germinate and become established in a variety of different soil types, including those derived from serpentine rock.  Once it is established, Cortaderia is extremely competitive with nearby plants and tree seedlings.  By the second year, a plant can be over 1 m tall and produce seeds of its own."  (2)"If young plants reach a suitable size, they are capable of flowering after one to two years... " (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://www.hear.org/hnis/reports/HNIS-CorJub.pdf
7.01 "Translocation of machinery/equipment (local): Soil containing C. jubata seeds and underground stems can adhere to machinery that transferred to new habitats (SCW, Undated)." http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
7.02 (1)"It is used as an ornamental in landscaping." (1)http://www.nps.gov/archive/redw/pampas.htm
7.03 (1)"It provides green forage during dry summer months and can be used as a substitute for hay." [Because it can be used as a substitue for hay].  (2)"Additionally, C. jubata seeds stick to fruit such as kiwifruit, seriously degrading fruit quality." (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
7.04 (1)"Seed, primarily wind-borne."  (2)Wind: Plants have a large potential impact because the seeds are lightweight and easily dispersed by wind (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
7.05 "Water currents: Seeds are also spread by water (SCW, Undated)."Seed, primarily wind-borne." http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
7.06 No evidence of dispersal by birds.  
7.07 "Additionally, C. jubata seeds stick to fruit such as kiwifruit, seriously degrading fruit quality." [If they can stick to kiwifruit it is likely that they stick to animals too]. http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=
7.08 No evidence.  
8.01 (1)"Plants produces millions of seeds that develop without pollination."  (2)Prolific seed production (3)Jubatagrass can produce over 100,000 wind-dispersed seeds from a single inflorescence. (1)http://www.nps.gov/archive/redw/pampas.htm  (2)http://www.issg.org/database/species/ecology.asp?si=375&fr=1&sts=  (3)Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata). Weed Science 52 (4) : 525-530 July 2004
8.02 "The percentages of germinable and viable seeds were not significantly different, indicating that jubatagrass does not have a primary dormancy. This was supported by field experiments demonstrating that seeds do not persist under natural conditions for more than 6 mo." Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata). Weed Science 52 (4) : 525-530 July 2004
8.03 (1)"Chemical: Treat with herbicide such as Roundup, Galant, or Velpar (Timmins and Mackenzie, 1995). "Sensitive to glyphosate which has been aerially applied on Maui at 2% of product with surfactant, sprayed to wet all plant surfaces.   The same mixture has been used effectively for aerial spot applications using a "spray ball applicator" used to spot spray marijuana (E. Tamura, HDOA.). Davenhill (13) in New Zealand reported glyphosate at 4lb/acre, hexazinone at 4.8 lb/acre and imazapyr at 1.78 lb/acre were effective, as were two herbicides not yet registered for forest use in Hawaii, haloxyfop and clethodim." (Motooka et al., 2002)."   (2)"Adequate control of Cortaderia can be achieved with mechanical or chemical methods or both.  If there are low densities of the weed or if the individual plants are quite small, physical removal is effective and minimizes impact on the native plant community.  In the case of high densities or well established plants, Cortaderia is best controlled with herbicide treatments." (1)http://www.hear.org/pier/species/cortaderia_jubata.htm  (2)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf
8.04 (1)"It can be grazed within 0.3 to 0.5 m of the base of the plant without severe damage."  (2)" … and cultural strategies, such as prescription burning, do not provide long-term control and result in rapid resprouting." (1)http://tncweeds.ucdavis.edu/esadocs/documnts/cortjub.rtf  (2)http://66.102.7.104/search?q=cache:TTnF2VPRmE8J:
www.elkhornslough.org/plants/weeds.PDF+%22Cortaderia+jubata
%22+runner%7Crunners&hl=en&gl=us&ct=clnk&cd=3
8.05  "Unfortunately, no biological control efforts have yet been investigated, and cultural strategies, such as prescription burning, do not provide long-term control and result in rapid resprouting." Drewitz, Jennifer J.; DiTomaso, Joseph M. Seed biology of jubatagrass (Cortaderia jubata). Weed Science 52 (4) : 525-530 July 2004

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This page was created on 26 December 2006 by JS and was last updated on 30 August 2017 by PT.