Pacific Island Ecosystems at Risk (PIER)

Pritchardia thurstonii

RISK ASSESSMENT RESULTS: Low risk, score: -4

Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment
  Pritchardia thrustonii (Common Names: Thurstons Fan Palm, Lau Fan Palm ) Synonym- Styloma thurstonii, Family - Arecaceae. Answer Score
1.01 Is the species highly domesticated? n 0
1.02 Has the species become naturalized where grown? n  
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) n 0
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 n -2
3.02 Garden/amenity/disturbance weed                              y = 1*multiplier (see Append 2) n 0
3.03 Agricultural/forestry/horticultural weed                         y = 2*multiplier (see Append 2) n 0
3.04 Environmental weed                                                     y = 2*multiplier (see Append 2) n 0
3.05 Congeneric weed                                                          y = 1*multiplier (see Append 2) n 0
4.01 Produces spines, thorns or burrs n 0
4.02 Allelopathic n 0
4.03 Parasitic n 0
4.04 Unpalatable to grazing animals    
4.05 Toxic to animals n 0
4.06 Host for recognized pests and pathogens y 1
4.07 Causes allergies or is otherwise toxic to humans n 0
4.08 Creates a fire hazard in natural ecosystems n 0
4.09 Is a shade tolerant plant at some stage of its life cycle n 0
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 n 0
5.01 Aquatic n 0
5.02 Grass n 0
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 n -1
6.04 Self-compatible or apomictic    
6.05 Requires specialist pollinators n 0
6.06 Reproduction by vegetative fragmentation n -1
6.07 Minimum generative time (years)                 1 year = 1, 2 or 3 years = 0, 4+ years = -1 4 -1
7.01 Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas) n -1
7.02 Propagules dispersed intentionally by people y 1
7.03 Propagules likely to disperse as a produce contaminant n -1
7.04 Propagules adapted to wind dispersal n -1
7.05 Propagules water dispersed y 1
7.06 Propagules bird dispersed    
7.07 Propagules dispersed by other animals (externally) n -1
7.08 Propagules survive passage through the gut    
8.01 Prolific seed production (>1000/m2) n -1
8.02 Evidence that a persistent propagule bank is formed (>1 yr)    
8.03 Well controlled by herbicides    
8.04 Tolerates, or benefits from, mutilation, cultivation, or fire    
8.05 Effective natural enemies present locally (e.g. introduced biocontrol agents)    
  Total score:   -4

Supporting data:

  Notes Reference
1.01 No evidence  
1.02 No evidence of naturalization  
1.03 No evidence  
2.01 (1)Lau group in the Fiji islands, introduced on other pacific islands. (1)http://www.pacsoa.org.au/palms/Pritchardia/thurstonii.html
2.02 Tropical, on coralline limestone sands, subject to salt atmosphere and soils. http://www.pacsoa.org.au/palms/Pritchardia/thurstonii.html
2.03 Hardiness: USDA Zone 10b: to 1.7° C (35° F), USDA Zone 11: above 4.5° C (40° F). http://davesgarden.com/pf/go/68401/index.html
2.04 (1)Lau group in the Fiji islands, introduced on other pacific islands. (1)http://www.pacsoa.org.au/palms/Pritchardia/thurstonii.html
2.05 (1)Introduced to Pompano Beach, Florida.  (2)In Hawaii it is probably a more recent introduction than P. pacifica. (1)http://davesgarden.com/pf/go/68401/index.html  (2)Staples, W George and Derral H Herbst. 2005. A Tropical Garden Flora. Bishop Museum Press. Honolulu. Hawaii. Page 626
3.01 No evidence of naturalization  
3.02 No evidence  
3.03 No evidence  
3.04 No evidence  
3.05 No evidence  
4.01 No evidence of such structures. http://www.pacsoa.org.au/palms/Pritchardia/thurstonii.html
4.02 No evidence  
4.03 No evidence  
4.04    
4.05 No evidence  
4.06 (1)Pritchardii thurstonii is on the 'Lethal Yellowing List' and the State Departments of Louisiana, Texas and Mississipi restrict the entry of this species from the State of Florida, the Commonwealth of Puerto Rico, and the Territory of Guam where lethal yellowing and its host P. thurstonii is  prevalant.  (2)Phytophthora nicotiana was the fungi speceis listed to be associated with Pritchardia thurstonii. [No evidence that this is an economic pest]. (1)http://www.thepalmshop.com/ly.html  AND  http://6