Prosopis pallida (Willd.) Kunth

Title: Prosopis pallida (Willd.) Kunth

Scientific Name: Prosopis pallida (Willd.) Kunth

Common Name: mesquite, algaroba

Source & more images (via ALA)

Habitat: The semi-arid subtropics and tropics, mostly in better watered valley bottoms, gullies and intermittently flowing streams beds, occurring on a range of sands and sandy loams, usually at altitudes below 1500m. Plants spread readily from these water courses to the adjacent higher ground, under the influence of grazing and favourable summer rains, and are often found along roadsides near areas of habituation. In Australia all forms of mesquite tend to grow on heavier soils which support open woodland or grassland. (Parsons and Cuthbertson, 1992).

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1.Germination requirements? “Seeds germinate in summer after periods of very warm temperatures and rain.” Requires natural seasonal disturbance. Parsons & Cuthbertson (2001)

2. Establishment requirements? Requires a period of very warm temperatures. “Temperature appears to be more important than available water.” Optimal germination temperature is 29°C. “Honey mesquite seeds must be covered with a small amount of soil or dung for seedlings to establish. Seeds that germinate on the soil surface usually die.” Requires specific conditions to germinate. Parsons & Cuthbertson (2001); Steinberg (2001)

3. How much disturbance is required? Commonly found in intermittently flowing streambeds from where they spread into adjacent areas depending upon favourable rainfall. “…often found along roadsides near areas of habitation.” Occur mostly in highly disturbed areas (riverbeds, watercourses) in open areas. “In Australia, all forms of mesquite tend to grow on heavier soils which support open woodland or grassland.” Parsons & Cuthbertson (2001)

GROWTH / COMPETITIVE

4. Life form? Shrubs to small trees, nominally deciduous. Part of the Fabaceae family, mesquites are leguminous. Parsons & Cuthbertson (2001)

5. Allelopathic properties? Extracts from the ground litter (mesquite pods and leaves) have an allelopathic effect on germinating seeds of other plant species. Parsons & Cuthbertson (2001)

6. Tolerates herb pressure? Grazing animals eats pods, but spines may discourage animals from browsing on the leaves and stems. “Livestock do not consume the foliage to any great extent. Foliage consumption is high only during drought years.” Grazing does not affect the survival or reproductive ability of the tree. Parsons & Cuthbertson (2001); Steinberg (2001)

7. Normal growth rate? Shoot growth is slow (compared to root growth). Maximum growth rate may be less than other species of similar life form. Parsons & Cuthbertson (2001)

8. Stress tolerance to frost, drought, w/logg, sal. etc? In the U.S., mesquite is found in areas where average minimum temperature is –5°C and the frost-free growing season is longer than 200 days. The deep root system (15 to 20 metres) would ensure most trees survive periods of drought. “Fire mortality is usually low in honey mesquite. Following most range fires, honey mesquite is top-killed and then resprouts.” Survives fire. Information on tolerance to salt or waterlogging is not available. Steinberg (2001);Parsons & Cuthbertson (2001)

REPRODUCTION

9. Reproductive system? “Deciduous shrubs or small trees, reproducing by seed and suckers.” Reproduces sexually and vegetatively. Parsons & Cuthbertson (2001)

10. Number of propagules produced? “…honey mesquite produces pods in… abundance.” Trees produce more than 100 pods per season, and in a Californian study, each pod contained an average of 12 seeds. Produces between 1,000 and 2,000 seeds .Steinberg (2001)

11. Propagule longevity? “Little is known about honey mesquite seed banks [or] seed longevity in the field.” “Mesquite seeds have a relatively short seed longevity when the pods are kept on the soil surface. Within 12 months, less than 20% of the seeds are still viable in good seed production years while <0.1% remain viable in some years.” Seeds survive less than 5 years. Owens et al (nd)

12. Reproductive period? “Maximum ages that plants attain is unclear. Near Amarillo, Texas, the maximum age of plants within a stand of multi-stemmed honey mesquites ranged from 40 to 110 years. On the Rio Grande Plains of Texas, Archer found that 89% to 93% of honey mesquite plants were less than 100 years old, and the maximum age of plants sampled was 172 to 217 years.” Plants are very long-lived (more than 10 years). Steinberg (2001)

13. Time to reproductive maturity? “Young plants do not flower until they are 2 to 3 years old and from 1 to 1.5 metres high.” “Young plants do not flower until they are 2 to 3 years old and from 1 to 1.5 metres high.”

DISPERSAL

14. Number of mechanisms? Prosopis spp. spread is mostly by seed. Both livestock and native animals consume the seed pods, and many of the seeds pass through the digestive system intact. The pods and seeds float, so they may be dispersed long distances in floodwater. Propagules spread by water and animals. Parsons & Cuthbertson (2001)

15. How far do they disperse? Floodwaters are likely to spread seed much greater than one kilometre, animals to a lesser extent. Parsons & Cuthbertson (2001)

Impact Assessment

RECREATION

1. Restrict human access? In Western Australia, “because of their thicket-forming characteristics, they…limit ingress to watering points.” Dense patches would create an impediment to accessing waterways. P & C (2001)

2. Reduce tourism? Dense patches limiting access to waterways may affect some recreational activities. P & C (2001)

3. Injurious to people? No toxic principles, however, the stems are “armed with paired stipular spines just above each leaf axil.” A deciduous shrub, the spines are present all year. P & C (2001)

4. Damage to cultural sites? Root system not documented as being vigorous; not known to cause structural damage. The plant can grow as a many stemmed shrub 1 to 3 metres high, large single-stemmed tree 6 to 15 metres high, or branching almost from the base and forming dense thickets 5 to 8 metres high. Dense patches would be obvious and create a moderate negative visual effect. P & C (2001)

ABIOTIC

5. Impact flow? Terrestrial species. P & C (2001)

6. Impact water quality? Terrestrial species. P & C (2001)

7. Increase soil erosion? The plant was grown in, “Pakistan and India…to combat erosion.” However, due to the plant removing all grass cover under the canopy, “…erosion problems are exacerbated.” Moderate probability of large scale soil movement. P & C (2001)

8. Reduce biomass? “In Australia, all forms of mesquite tend to grow on heavier soils which support open-woodland or grassland. They spread rapidly [which] usually results in the complete loss of grass cover.” Would increase biomass. P & C (2001)

9. Change fire regime? With increased biomass in grassland situations, dense infestations may result in a moderate change to both the frequency and intensity of fire risk.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC=Plains grassy woodland (E); CMA=North Central; Bioreg=Victorian Riverina; VH CLIMATE potential. Mesquites tend to grow in open-woodland or grassland situations where they spread rapidly. The mass of surface roots usually results in the complete loss of grass cover. Major impact on grasses and displacement of mid storey species. P & C (2001)

10(b) Impact on medium value EVC? EVC=Box Ironbark forest (D); CMA=North Central; Bioreg=Goldfields; M CLIMATE potential. Impact similar to above, however, medium CLIMATE potential only, limiting population size.

10(c) Impact on low value EVC? Appears unlikely to occur in any low value EVC in Victoria.

11. Impact on structure? In open-woodland or grassland situations, “competition from the mass of their surface roots usually results in the complete loss of grass cover. The allelopathic effects from ground litter (mesquite pods and leaves) extracts, prevents the seeds of other species germinating.” Major effect on the lower and mid strata. P & C (2001)

12. Effect on threatened flora?

FAUNA

13. Effect on threatened fauna?

14. Effect on non-threatened fauna? “Prosopis spp. are aggressive invaders and competitors. Because of their thicket-forming characteristics, they reduce available grazing area and limit ingress to watering points.” Dense infestations would reduce habitat of native fauna. P & C (2001)

15. Benefits fauna? “Pods are sweet, fairly nutritious, and relished by livestock, but heavy consumption can cause digestive problems.” Possible limited food source for native fauna. (California Department of Food and Agriculture, Camelthorn).

16. Injurious to fauna? Although the stems are armed with spines, there is no evidence to indicate they injure animals. Potential exists. P & C (2001)

PEST ANIMAL

17. Food source to pests? “Pods are eaten and then dispersed by domestic and wild animals.” Potential food source to pest animals such as rabbits. (USDA)

18. Provides harbor? Where plant grows as a thicket, it may provide harbor for pest bird species.

AGRICULTURE

19. Impact yield? “Prosopis spp. are aggressive invaders and competitors. Because of their thicket-forming characteristics, they reduce available grazing area and limit ingress to watering points. In some situations competition from the roots results in the complete loss of grass cover.” Reduces carrying capacity. P & C (2001)

20. Impact quality? Not a weed of cropping. Not known to affect quality of yield.

21. Affect land values? Reproduces sexually and vegetatively. Dense infestations can be difficult to eliminate due to the longevity of the seed. In southwestern United States, “Many species of mesquite respond positively to overgrazing and grasslands are subsequently converted to mesquite brushlands. Conversion back is very difficult and temporary with reduced grazing pressure.” Dense infestation likely to have a major impact on land value. (California Department of Food and Agriculture)

22. Change land use? As above. “American experience convincingly demonstrates that the best means of obtaining control of larger colonies is by integrating available techniques, including mechanical, cultural, chemical and biological.” This may lead to extended non-availability of grazing land. P & C (2001)

23. Increase harvest costs? In Western Australia infestations, “hinder mustering.” Increased time to harvest animals. P & C (2001)

24. Disease host/vector? None evident.

Feedback

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

The entry of this assessment was made possible through the generous support of an anonymous donor.

Attachments:

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referenced by (2)

wra702: Common Name - A (via algaroba)wra7: Prosopis spp.

Article: wra7255 (permalink)
Categories: :wra:p, :wra:inv1, :wra:invmh, :wra:inv2, :wra:invml, :wra:inv3, :wra:inv4, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:inv9, :wra:invh, :wra:inv10, :wra:inv11, :wra:invl, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impml, :wra:imp2, :wra:imp3, :wra:imph, :wra:imp4, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:impmh, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:impm, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 26 June 2012; 3:07:48 PM AEST

Author Name: Zheljana Peric
Author ID: zper12