Mimosa pigra L.

Title: Mimosa pigra L.

Scientific Name:

Mimosa pigra L.

Common Names:

mimosa, giant sensitive plant

Source & more images (ALA)

Habitat: Favours wet-dry tropical climate with annual rainfall between 750 and 2250 mm. Found most commonly in floodplains and riverbanks within soils ranging from black cracking clays to sandy clays to coarse siliceous sand although does not appear to grow preferentially in any soil type. Occurs in agricultural areas, coastland, disturbed areas, natural forest, planted forests, range/grasslands, riparian zones, scrub/shrublands, urban areas, water courses, wetlands. (ISSG 2005). Wet places in the humid and subhumid tropics, occurring as a weed of roadsides, watercourses, drainage ditches, reservoirs, seasonally flooded wetlands, lowland fields and occasionally tropical mountain valleys (Parsons & Cuthbertson 2001). soil or landuse is not presently suitable.

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Seeds generally germinate when first wetted and have a high germination rate (ARMCANZ 2000). Opportunistic germinator.

2. Establishment requirements? Adapted to seasonally flooded habitats and can regenerate under some degree of canopy cover (Binggeli 1997).

3. How much disturbance is required? Establishes in ‘agricultural areas, coastland, disturbed areas, natural forest, planted forests, range/grasslands, riparian zones, scrub/shrublands, urban areas, water courses, wetlands’ (ISSG 2005). ‘Can also regenerate under a canopy of Melaleuca fringing the floodplain’ (Binggeli 1997).

GROWTH / COMPETITIVE

4. Life form? Leguminous, thorny shrub (ARMCANZ 2000).

5. Allelopathic properties? None described.

6. Tolerates herb pressure? Impalatable to mammalian herbivores but biological control agents (insect and fungal) are being used (ARMCANZ 2000). Neurostrota gunniella, particularly, has been found to stunt plants but insufficient to control the plant (Paynter 2002).

7. Normal growth rate? Smothers pastures and has densely covered river floodplain and swamp forest with monospecific thickets (ISSG 2005). Although seedlings are susceptible to competition from native grasses, once established will generally out-compete most flood plain species (Marko 1999).

8. Stress tolerance to frost, drought, w/logg, sal. etc? Can survive up to seven months drought. Can withstand flooding. Fire resistant and fire alone may stimulate re-growth and enhance seed germination. Tolerant to saline conditions. (Marko 1999)

REPRODUCTION

9. Reproductive system? Assumed that most of the seeds are produced by autogamy in Australia but is also bee-pollinated and possibly wind pollinated (ISSG 2005). Does not naturally reproduce vegetatively but can do from cut stems (Parsons & Cuthbertson 2001).

10. Number of propagules produced? Average production is 9000 seeds per square metre (ARMCANZ 2000). Per plant, production has been measured at up to 220,000 (ISSG 2005).

11. Propagule longevity? On sandy soils, seeds can survive at least 23 years, but viability will decrease more rapidly on clay soils (ARMCANZ 2000).

12. Reproductive period? Flowering will continue for as long as water is available. Species can form dense monocultures (ISSG 2005).

13. Time to reproductive maturity? Plants can begin flowering from 6 to 8 months after germination under ideal conditions (ARMCANZ 2000).

DISPERSAL

14. Number of mechanisms? Bristles covering the seed pods assist in water dispersal. Within catchments, spread by floodwaters. Also spread by vehicle movement and by animals (buffalo, cattle, horses, wallabies). Seeds can stick on magpie geese and other waders (ISSG 2005).

15. How far do they disperse? Due to the mechanisms of dispersal, it is assumed that seeds can spread over 1km.

Impact Assessment

RECREATION

1. Restrict human access? “This aggressive prickly shrub forms impenetrable thickets 4 to 5 metres high, making infested areas inaccessible to man” (Parsons & Cuthbertson 2001). “Traditional hunting areas have been choked by mimosa, so that people can no longer hunt [in some Aboriginal communities in NT]’ (CRC for Weed Management 2005). Dense infestations would create a major impediment to humans.

2. Reduce tourism? Infestations of M. pigra create, “…perceptions of degraded natural landscapes; reduced wildlife attractions; reduced area and access for tourism activities; reduced access to fishing, hunting and scenic areas” (ARMCANZ 2001). Dense infestations would have serious implications for recreational activities.

3. Injurious to people? “Stems are armed with broad-base prickles to 7 mm long” (Groves et al 1995). Prickles exist throughout the year. Potential for minor injury.

4. Damage to cultural sites? “…perceptions of degraded natural landscapes; reduced wildlife attractions; reduced area and access for tourism activities; reduced access to fishing, hunting and scenic areas” (ARMCANZ 2001). Infestations would create a moderate visual effect.

ABIOTIC

5. Impact flow? Terrestrial species invading, “…sedgeland and grassland communities on open floodplains” (Groves et al 1995).

6. Impact water quality? Terrestrial species.

7. Increase soil erosion? “A large central taproot penetrate 1 – 2 m into the soil, together with a lateral root system that extends up to 3.5 m from the stem” (Groves et al 1995). Unlikely to contribute to soil erosion.

8. Reduce biomass? The plant invades,“…sedgeland and grassland communities on open floodplains,” and can grow to a height of 6 m (Groves et al 1995). Biomass would increase.

9. Change fire regime? Mimosa is fire resistant (Marko 1999). In dense infestations, it would decrease horizontal continuity, thereby decreasing fire frequency and extent (Brooks et al 2004). Minor change to frequency of fire.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? Climate modelling predicts that this species is not likely to establish as a weedy species in Victoria. No impact on EVCs in Victoria.

10(b) Impact on medium value EVC? Climate modelling predicts that this species is not likely to establish as a weedy species in Victoria. No impact on EVCs in Victoria.

10(c) Impact on low value EVC? Climate modelling predicts that this species is not likely to establish as a weedy species in Victoria. No impact on EVCs in Victoria.

11. Impact on structure? “In Australia, a largely intact natural landscape has been completely altered. Some 450 km2 of floodplain and swamp forest have been covered by dense monospecific stands of M. pigra which have little understorey except for seedlings and suckers of M. pigra” (Groves et al 1995).

12. Effect on threatened flora? The potential for M. pigra to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations. No impact on threatened flora in Victoria.

FAUNA

13. Effect on threatened fauna? The potential for M. pigra to establish and naturalise in Victoria is highly unlikely due to ecoclimatic limitations. No impact on threatened fauna in Victoria.

14. Effect on non-threatened fauna? “Braithwaite et al. (1989) found that M. pigra thickets had fewer birds and lizards” (Groves et al 1995). Reduces habitat for fauna species.

15. Benefits fauna? “…the rare marsupial mouse Sminthopsis virginiae (Tarragon) has become more abundant as a result of M. pigra. It probably shelters from predators in the dense thickets” (Groves et al 1995). Provides some assistance to desirable species.

16. Injurious to fauna? Not documented as causing injury. Not toxic.

PEST ANIMAL

17. Food source to pests? Not known as a food source to pest animals.

18. Provides harbor? Not known to provide harbor to pest animals.

AGRICULTURE

19. Impact yield? “Occurring, as it does, in damp situations along riverbanks and billabongs, mimosa interferes with stock watering, [and] irrigation projects. It also moves out onto the drier floodplains away from rivers, where it smothers pastures, [and] reduces the available grazing area” (Parsons & Cuthbertson 2001). “The rate of population increase in river systems is rapid, with infestations able to double in area every 1.2 years” (Groves et al 1995). Major impact on carrying capacity.

20. Impact quality? Not known to affect quality of produce.

21. Affect land values? Primarily a weed of natural ecosystems, in the Northern Territory, it does occur on grazing land (ARMCANZ 2001). As an aggressive shrub that can spread rapidly reducing grazing and water resources, land prices may be somewhat affected.

22. Change land use? “If mimosa continues to spread, large stands could develop very quickly in pastoral and agricultural areas of eastern Queensland and in the Ord River region of Western Australia. The cost of mimosa control under these circumstances would be exorbitant” (ARMCANZ 2001). Land use may be seriously affected.

23. Increase harvest costs? Infestations make stock management and mustering difficult. Increase in time and labour to harvest animals (ARMCANZ 2001).

24. Disease host/vector? None evident

Feedback

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of The Weed's Network.

Attachments:

Present Distribution Mimosa pigra.doc
Potential Distribution Mimosa pigra.doc
483290.jpg
distribution_map (33).png

referenced by (2)

wra1009: Common Name - M (via mimosa)wra1001: Common Name - G (via giant sensitive plant)

Article: wra5354 (permalink)
Categories: :wra:m, :wra:inv1, :wra:inv2, :wra:invmh, :wra:inv3, :wra:inv4, :wra:inv5, :wra:invl, :wra:inv6, :wra:inv7, :wra:invh, :wra:inv8, :wra:inv9, :wra:invml, :wra:inv10, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:imp2, :wra:imp3, :wra:imp4, :wra:impml, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imph, :wra:imp12, :wra:imp13, :wra:imp14, :wra:impmh, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:impm, :wra:imp23, :wra:imp24
Date: 23 November 2009; 4:46:14 PM AEDT

Author Name: Jessica Mackay
Author ID: mackayj