Pacific Island Ecosystems at Risk (PIER)

Tabebuia aurea

RISK ASSESSMENT RESULTS: Low risk, score: 3 (low risk based on second screen)

Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment
  Tabebuia aurea (silver trumpet tree, yellow trumpet tree, caribbean trumpet tree)  Synonym: Tabebuia argentea Family- Bignoniaceae 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) 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 y 2
3.02 Garden/amenity/disturbance weed                              y = 1*multiplier (see Append 2) y 2
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) y 2
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 n 0
4.07 Causes allergies or is otherwise toxic to humans n 0
4.08 Creates a fire hazard in natural ecosystems    
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) n 0
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    
6.04 Self-compatible or apomictic y 1
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 y 1
7.05 Propagules water dispersed n -1
7.06 Propagules bird dispersed n -1
7.07 Propagules dispersed by other animals (externally) n -1
7.08 Propagules survive passage through the gut n -1
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 y 1
8.05 Effective natural enemies present locally (e.g. introduced biocontrol agents)    
  Total score:   3

Supporting data:

  Notes Reference
1.01 No evidence  
1.02 It is found in disturbed sites in Palm Beach and Broward County, as well as Puerto Rico and the Virgin Islands (Wunderlin, 1998 http://aquat1.ifas.ufl.edu/tabaur.html
1.03 No evidence  
2.01 "Silver trumpet tree is native to Brazil, where it grows in seasonal dry vegetation zones and is widely cultivated." Staples, W George and Derral H Herbst. 2005. A Tropical Garden Flora. Bishop Museum Press. Honolulu. Hawaii.
2.02 (1)"Silver trumpet tree is native to Brazil, where it grows in seasonal dry vegetation zones and is widely cultivated."  (2)It is found in disturbed sites in Palm Beach and Broward County, as well as Puerto Rico and the Virgin Islands (Wunderlin, 1998 (1)Staples, W George and Derral H Herbst. 2005. A Tropical Garden Flora. Bishop Museum Press. Honolulu. Hawaii.  (2)http://aquat1.ifas.ufl.edu/tabaur.html
2.03 Hardiness:
USDA Zone 10a: to -1.1°C (30° F)
USDA Zone 10b: to 1.7° C (35° F)
USDA Zone 11: above 4.5° C (40° F)		 http://davesgarden.com/pf/go/2559/index.html
2.04 "Silver trumpet tree is native to Brazil, where it grows in seasonal dry vegetation zones and is widely cultivated." Staples, W George and Derral H Herbst. 2005. A Tropical Garden Flora. Bishop Museum Press. Honolulu. Hawaii.
2.05 It is found in disturbed sites in Palm Beach and Broward County, as well as Puerto Rico and the Virgin Islands (Wunderlin, 1998 http://aquat1.ifas.ufl.edu/tabaur.html
3.01 It is found in disturbed sites in Palm Beach and Broward County, as well as Puerto Rico and the Virgin Islands (Wunderlin, 1998 http://aquat1.ifas.ufl.edu/tabaur.html
3.02 It is found in disturbed sites in Palm Beach and Broward County, as well as Puerto Rico and the Virgin Islands (Wunderlin, 1998 http://aquat1.ifas.ufl.edu/tabaur.html
3.03 No evidence  
3.04 No evidence  
3.05 (1)Tabebuia heterophylla - "Invasive in Hawai‘i. Reported invasive on Diego Garcia and naturalizing on Kwajalein (Whistler and Steele, 1999). Naturalized in some locations on Nimitz Hill, Guam (Bart Lawrence, personal communication). Reported to be a problem species on Diego Garcia, Indian Ocean."  (2)"General impacts of T. heterophylla:
On the island Mauritius, Parnell et al. (1989) found that, "T. heterophylla was spreading rapidly on the island, with small numbers of mature trees present but abundant young plants and seedlings. It appears to grow faster than any native or exotic tree on the island. Most T. heterophylla bear leaves and branches almost to the base and cast a deep shade under which virtually no other species grow. T. heterophylla is deciduous and its thick litter layer may also prevent the growth of native seedlings.
PIER (2004) states that, "T. heterophylla is invasive in Hawai‘i. It is also reported invasive on Diego Garcia and naturalizing on Kwajalein (Whistler and Steele, 1999). T. heterophylla is also naturalized in some locations on Nimitz Hill, Guam (Bart Lawrence, personal communication)."
Zimmerman et al. (2000) state that, "T. heterophylla readily invades pasture via seed." In their study, Zimmerman et al. (2000) state that, "T. heterophylla appears to facilitate the colonization of many common forest species that are unable to establish in recently abandoned pasture."
Weaver (1990) states that, "T. heterophylla regenerates and forms pure stands on grasslands and degraded soils, in particular on exposed upper slopes and ridges, where competition from faster growing, larger, and more tolerant trees is lacking." In the seedling and sapling stages, T. heterophylla is an aggressive pioneer (Weaver, 1990), and it can maintain viable populations in both dry and moist forest habitats (Cordero and Molano, 1996)."
 		 (1)http://www.hear.org/Pier/species/tabebuia_heterophylla.htm  (2)http://www.invasivespecies.net/database/species
/ecology.asp?si=868&fr=1&sts=
4.01 No evidence of such traits. http://www.scielo.org.ar/pdf/phyton/n1/n1a27.pdf
4.02 No evidence  
4.03 No evidence  
4.04 " ...Herbivory on seedlings was lower in the Pantanal than in the cerrado. Although seedlings of T. aurea from the Pantanal suffered the highest rates of herbivory in the cerrado, they survived equally to seedling genotypes from the cerrado. Tabebuia aurea had a higher mortality in both the cerrado and under controlled environmental conditions....' [Dont know palatability to livestock]. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1365-2745.2006.01133.x