Impact Assessment Record
Scientific name: Acacia farnesiana (L.) Willd.
QUESTION
Social
1. Restrict human access?
2. Reduce tourism?
Common name: mimosa bush
COMMENTS
RATING
CONFIDENCE
Shrub to 3 m high with spiny stems (Wrigley, Fagg 1996), grows near water courses (Harden 2002) and can form
almost pure stands (Foroughbakhch 1992) and sometimes “impenetrable thickets… limiting access to water”
(ISSG 2006) – major impediment to access waterways
Spiny appendages (stipules, to 25 mm long) at the base of the leaflets (Richardson et al 2006) – may effect some
recreational uses
H
M
MH
MH
3. Injurious to people?
Spiny appendages (stipules, to 25 mm long) at the base of the leaflets (Richardson et al 2006) – large spines
H
MH
4. Damage to cultural
sites?
Shrub to 3 m high (Wrigley, Fagg 1996) and can form almost pure stands (Foroughbakhch 1992) – moderate
visual effect
ML
M
Abiotic
5. Impact flow?
Although it grows near watercourses (Harden 2002), it does not appear to affect water flow
L
M
ML
M
6. Impact water quality?
Grows near watercourses and in dense thickets (Harden 2002) up to 3 m high Shrub to 3 m high (Wrigley, Fagg
1996) – may have a minor effect on light levels
7. Increase soil erosion?
“considered useful for soil stabilization in degraded drylands” (Parrotta 1992) – is likely to decrease the
probability of soil erosion
L
MH
8. Reduce biomass?
Potential invader of grasslands (Polley et al 2002) – likely to increase biomass
L
H
9. Change fire regime?
“Although the aerial portions may be killed by fire, this plant soon regenerates from basal shoots” (ISSG 2006).
As A. farnesiana invades “pastures, fallow land and disturbed natural vegetation” (Foroughbakhch 1992) it is
likely to greatly change the frequency and intensity of fire risk
H
M
EVC = Semi-arid Woodland (V); CMA = Mallee; Bioregion = Murray Mallee; VH CLIMATE potential.
A. farnesiana is a potential invader of grasslands (Polley et al 2002) and has “aggressive pioneer characteristics in
the invasion of pastures, fallow land and disturbed natural vegetation… Almost pure stands… developed in some
areas” (Foroughbakhch 1992), indeed, it was found that biomass increased with increasing planting density (Goel,
Behl 2004)
Likely to form a monoculture within the shrub layer; displaces all spp. within a strata/layer
H
H
Community Habitat
10. Impact on composition
(a) high value EVC
Impact Assessment Record
Scientific name: Acacia farnesiana (L.) Willd.
QUESTION
(b) medium value EVC
(c) low value EVC
11. Impact on structure?
12. Effect on threatened
flora?
Fauna
13. Effect on threatened
fauna?
14. Effect on nonthreatened fauna?
15. Benefits fauna?
16. Injurious to fauna?
Pest Animal
17. Food source to pests?
Common name: mimosa bush
COMMENTS
RATING
CONFIDENCE
EVC = Grassy Riverine Forest (D); CMA = North Central; Bioregion = Murray Fans; VH CLIMATE potential.
A. farnesiana is a potential invader of grasslands (Polley et al 2002) and has “aggressive pioneer characteristics in
the invasion of pastures, fallow land and disturbed natural vegetation… Almost pure stands… developed in some
areas” (Foroughbakhch 1992), indeed, it was found that biomass increased with increasing planting density (Goel,
Behl 2004)
Likely to form a monoculture within the shrub layer; displaces all spp. within a strata/layer
EVC = Sandstone Ridge Shrubland (LC); CMA = Mallee; Bioregion = Lowan Mallee; VH CLIMATE potential.
A. farnesiana is a potential invader of grasslands (Polley et al 2002) and has “aggressive pioneer characteristics in
the invasion of pastures, fallow land and disturbed natural vegetation… Almost pure stands… developed in some
areas” (Foroughbakhch 1992), indeed, it was found that biomass increased with increasing planting density (Goel,
Behl 2004)
Likely to form a monoculture within the shrub layer; displaces all spp. within a strata/layer
A. farnesiana is a potential invader of grasslands (Polley et al 2002) and has “aggressive pioneer characteristics in
the invasion of pastures, fallow land and disturbed natural vegetation… Almost pure stands… developed in some
areas” (Foroughbakhch 1992), indeed, it was found that biomass increased with increasing planting density (Goel,
Behl 2004) – major effects on all layers. Forms monoculture.
It has “aggressive pioneer characteristics in the invasion of pastures, fallow land and disturbed natural
vegetation… [forms] almost pure stands” (Foroughbakhch 1992) – likely to effect threatened flora but this was
not identified in the literature.
H
H
H
H
H
H
MH
L
It has “aggressive pioneer characteristics in the invasion of pastures, fallow land and disturbed natural
vegetation… [forms] almost pure stands” (Foroughbakhch 1992) – likely to effect habitat of threatened fauna was
not identified in the literature.
As it forms “impenetrable thickets” (ISSG 2006) it is likely to change habitat dramatically which may lead to the
possible extinction of non-threatened fauna
As it is a prickly shrub (Wrigley, Fagg 1996) it is likely to provide harbour for small birds, as well as provide
nectar for nectar-feeders – provides an important alternative food source and harbour to desirable species
The spiny appendages (stipules, to 25 mm long) at the base of the leaflets (Richardson et al 2006) – large spines
likely to be dangerous to fauna
MH
L
H
M
ML
M
H
MH
“The seed pods are nutritious and are readily eaten by ungulates” (ISSG 2006), e.g. wild horses, goats and pigs –
supplies food for one or more minor pests spp.
ML
M
Impact Assessment Record
Scientific name: Acacia farnesiana (L.) Willd.
QUESTION
18. Provides harbor?
Agriculture
19. Impact yield?
20. Impact quality?
21. Affect land value?
22. Change land use?
23. Increase harvest costs?
24. Disease host/vector?
Common name: mimosa bush
RATING
CONFIDENCE
As it forms “impenetrable thickets” (ISSG 2006) it is likely to provide harbour and permanent warrens for foxes
and rabbits throughout the year
COMMENTS
H
M
It is persistent “in heavily grazed, mechanically cut, and herbicide-treated pastures” (Parrotta 1992) and although
in Australia “pastoralists have long tolerated it as drought forage” (Kull, Rangan 2008) it is digested poorly in
sheep (Ramirez, Ledezma-Torres 1997) – may affect pasture quantity and therefore livestock access to feed –
major impact on quantity of produce (5-20%)
A known seed contaminant of hay from the top end in the Northern Territory (CLMA 2004) - this may lead to
produce being rejected for sale or export
“As it often forms thorny thickets along some watercourses in Australia…can also hinder access to water” (ISSG
2006) – may decrease land value > 10%
“As it often forms thorny thickets along some watercourses in Australia, it can be a considerable nuisance during
mustering and can also hinder access to water” (ISSG 2006). “Due to its prolific seed production, palatability to
livestock, and rapid germination on disturbed soils, aroma can rapidly colonize pastures, often forming dense
stands” (Parrotta 1992) – the fact that it is so hard to control and affects access to water may result in
downgrading of the priority land use
“As it often forms thorny thickets along some watercourses in Australia, it can be a considerable nuisance during
mustering and can also hinder access to water” (ISSG 2006) – more time and labour would be required to regain
access to waterways and to muster livestock
None mentioned in the literature
MH
MH
H
M
H
M
MH
M
H
M
M
L