Pacific Island Ecosystems at Risk (PIER)
Acacia stenophylla
RISK ASSESSMENT RESULTS: Low risk, score: 2 (low risk based on second screen)
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Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i. Information on Risk Assessments Original risk assessment |
| Acacia stenophylla (river cooba, shoestring acacia, native willow) | 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) | 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 | 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) | ||
| 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 | n | -1 |
| 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 | ||
| 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 | y | 1 |
| 5.01 | Aquatic | n | 0 |
| 5.02 | Grass | n | 0 |
| 5.03 | Nitrogen fixing woody plant | y | 1 |
| 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 | ||
| 6.05 | Requires specialist pollinators | n | 0 |
| 6.06 | Reproduction by vegetative fragmentation | y | 1 |
| 6.07 | Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1 | 0 | |
| 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 | 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 | 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: | 2 |
Supporting data:
|
Notes |
Reference |
|
|
1.01 |
No evidence |
|
|
1.02 |
No evidence of naturalization. |
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|
1.03 |
No evidence |
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|
2.01 |
(1)Review of Natural Distribution- This species has an extensive distribution in central and eastern Australia. It is found from the River Murray in South Australia and Victoria to western New South Wales, Queensland and Northern Territory, with a small e |
(1)Reproduced from the Forestry Compendium. |
|
2.02 |
||
|
2.03 |
(1)The latitudinal range of A. stenophylla is from17 to
36°S, but the main occurrence is from 23 to 33°S. The altitudinal range is
from near sea level to about 625 m, but it is mainly found at altitudes from
50 to 325 m. |
(1)Reproduced from the Forestry Compendium. |
|
2.04 |
The Western Australian Herbarium has records of a small disjunct population near Wittenoom in the Pilbara region of Western Australia; it is some considerable distance west of the small extension from the Northern Territory into Western Australia. |
Reproduced from the Forestry Compendium. |
|
2.05 |
(1)A. stenophylla has not been widely introduced into any country. Trials with this species have been reported in Australia (House et al., 1998; Ryan and Bell, 1991; Marcar et al., 2000), India (Bisht and Toky, 1991; Bhatnagar and Chopra, 1988; Hussain et |
Reproduced from the Forestry Compendium. |
|
3.01 |
(1)Planted in several countries but no evidence of naturalization. (2)The trees are moderately drought tolerant but cannot be naturalized to subsist on the annual rainfall in the desert southwest (U.S.). |
(1)Reproduced from the Forestry Compendium. |
|
3.02 |
No evidence |
|
|
3.03 |
No evidence |
|
|
3.04 |
A. stenophylla is considered a woody weed in parts of the Channel country in north-western Queensland. The best method of control has been by use of 2,4,5-T, however the most practical was burning (Pressland et al., 1989). [No other evidence other than th |
Reproduced from the Forestry Compendium. |
|
3.05 |
Five Acacia species are listes as invasice - A. confusa, A. farnesiana, A. mearnsii, A. melanoxyllon and A. julibrissin. |
http://www.issg.org/database/species/search.asp?sts= |
|
4.01 |
Thorns: None |
http://www.aridzonetrees.com/AZT%20Interactive%20 |
|
4.02 |
No evidence |
|
|
4.03 |
No evidence |
|
|
4.04 |
It is rarely browsed by cattle (Cunningham et al., 1981) but it is palatable to sheep (Everist, 1969) and could be a useful fodder reserve in droughts. |
Reproduced from the Forestry Compendium. |
|
4.05 |
No evidence |
|
|
4.06 |
(1)Symptoms of bunchy top (loss of apical dominance and development of a large number of side shoots from the axils of the condensed stem) due to the strawberry thrip (Scirtothrips dorsalis) were found in glasshouse-grown A. stenophylla. |
Reproduced from the Forestry Compendium. |
|
4.07 |
Probably not - Seeds and pods were roasted and used by Australian Aboriginals as a food source (Cribb and Cribb, 1976). |
Reproduced from the Forestry Compendium. |
|
4.08 |
It has evergreen foliage but is also a tree of arid areas and can form dense stands. |
(1)http://aridzonetrees.com/AZT%20Interactive%20 |
|
4.09 |
(1)Sun Exposure: Full sun, tolerates reflected sun (2)Exposure: Full Sun (3)Exposure: Full Sun |
(1)http://www.desert-tropicals.com/Plants/Fabaceae/Acacia_stenophylla.html
(2)http://www.smgrowers.com/products/plants/plantdisplay.asp |
|
4.1 |
(1)A. stenophylla is a nitrogen-fixing, small tree adapted to saline, heavy clay and waterlogged soils in arid and semi-arid areas located in temperate and subtropical climates especially where supplementary ground water is available. (2)The soils are mai |
(1) to (3)Reproduced from the Forestry Compendium. |
|
4.11 |
||
|
4.12 |
No specific data is readily available relating to cover, abundance or biomass. As noted above, A. stenophylla can be a dominant small tree on the edge of watercourses and is often found in monospecific stands. |
http://www.anbg.gov.au/cpbr/WfHC/Acacia-stenophylla/index.html |
|
5.01 |
||
|
5.02 |
A. stenophylla is typically a small tree with spreading, pendulous branches to form a bushy, rounded crown. It is typically 4-14 m tall, but may reach 20 m on very favourable sites. |
Reproduced from the Forestry Compendium. |
|
5.03 |
A. stenophylla is a nitrogen-fixing. |
Reproduced from the Forestry Compendium. |
|
5.04 |
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|
6.01 |
Flowers irregularly throughout the year, or in April to July with pods mature from September to December in Queensland. |
Reproduced from the Forestry Compendium. |
|
6.02 |
(1) Propagation by seed - 'Germination rate averages 73% …' (2)Seeds germinate prolifically (Lithgow, 1997). After major floods seedlings may be abundant along the flood-line but only a very small proportion of these persist (Cunningham et al., 1981). (3) |
(1)Reproduced from the Forestry Compendium. |
|
6.03 |
Don’t know |
|
|
6.04 |
||
|
6.05 |
Pollination in Acacias is usually by insects. |
Reproduced from the Forestry Compendium. |
|
6.06 |
(1)Ability to sucker. Coppicing and root suckering have been noted in natural stands (Searle, 1989; Bonney, 1994) and planted trees coppice well (Marcar et al., 2000). (2)Trees may produce suckers if roots are exposed to the sun or disturbed. |
(1)Reproduced from the Forestry Compendium. |
|
6.07 |
(1)Acacia stenophylla generally lives for more than 50 years (2)Moderate to rapid growth. |
(1)http://www.anbg.gov.au/cpbr/WfHC/Acacia-stenophylla |
|
7.01 |
Probably not - no evidence that the propagules have any means of attachment. |
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|
7.02 |
(1)It has potential for high value furniture timber. (2)The habit of A. stenophylla renders it suitable for use as an ornamental. It is used in California and Arizona as a feature plant and a source of light shade for sensitive underplantings. |
Reproduced from the Forestry Compendium. |
|
7.03 |
Probably not - relatively large seeds. 'Seeds longitudinal in the pod, brown, broadly elliptical to oblong-elliptic in shape, 7-9 mm long, 5-6 mm wide, with a small white aril. The seed is not easily separated from the pod, which breaks up into single-see |
Reproduced from the Forestry Compendium. |
|
7.04 |
Seeds longitudinal in the pod, brown, broadly elliptical to oblong-elliptic in shape, 7-9 mm long, 5-6 mm wide, with a small white aril. The seed is not easily separated from the pod, which breaks up into single-seed units. [Probably not - no evidence of |
Reproduced from the Forestry Compendium. |
|
7.05 |
(1)A. stenophylla occurs on plains and gentle slopes and is common on the margins of watercourses, river flood plains, and depressions. (2)Seeds germinate prolifically (Lithgow, 1997). After major floods seedlings may be abundant along the flood-line but |
(1)Reproduced from the Forestry Compendium. |
|
7.06 |
Seeds longitudinal in the pod, brown, broadly elliptical to oblong-elliptic in shape, 7-9 mm long, 5-6 mm wide, with a small white aril. The seed is not easily separated from the pod, which breaks up into single-seed units. [Probably dispersed by gravity] |
Reproduced from the Forestry Compendium. |
|
7.07 |
Probably not - no evidence that the propagules have any means of attachment. |
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|
7.08 |
No evidence of ingestion by animals. |
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|
8.01 |
Pods are grey, bluish-grey or brown, strongly constricted between the seeds, 10-20 cm long by 1 cm broad, straight or curved, slightly wrinkled over the seeds. Seeds longitudinal in the pod, brown, broadly elliptical to oblong-elliptic in shape, 7-9 mm lo |
Reproduced from the Forestry Compendium. |
|
8.02 |
Probably yes - a legume with relatively large seeds. |
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|
8.03 |
A. stenophylla is considered a woody weed in parts of the Channel country in north-western Queensland. The best method of control has been by use of 2,4,5-T, however the most practical was burning (Pressland et al., 1989). |
Reproduced from the Forestry Compendium. |
|
8.04 |
(1)regenerate rapidly; coppice (2)Acacia stenophylla displays moderate to fast growth. It may sucker on extremely poor sites or if the roots are damaged. It will coppice when young or in favourable conditions (Boxshall and Jenkyn, 2001). |
(1)Reproduced from the Forestry Compendium. |
|
8.05 |
Don’t know. |
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This page created 23 December 2006