Family: Fabaceae

Acacia nilotica (synonym Vachellia nilotica), also known as the gum arabic tree, is a fast-growing, thorny legume native to Africa and the Indian subcontinent. It has feathery leaves, bright yellow flowers, and woody seed pods, and produces a gum historically valued for medicinal and commercial uses. The tree is highly adaptable to different soils and climates, fixes nitrogen to enrich the soil, and is often used for shade, erosion control, and agroforestry projects.

While it has many benefits, Acacia nilotica can also spread quickly in areas outside its native range. Its seeds remain viable in the soil for many years, and dense thickets can outcompete native plants, alter habitats, and limit grazing access. Because of these traits, careful management is recommended when planting this species to balance its usefulness with potential ecological risks.

High Risk Traits:

• Naturalized beyond native range: Known to be invasive in regions like Australia and Java.
  
• Agricultural/forestry/horticultural weed: Considered a Weed of National Significance in Australia, impacting pastures and soil quality.
  
• Environmental weed: Converts grasslands to shrublands, threatening native ecosystems.
  
• Forms dense thickets: Can dominate landscapes, reducing biodiversity.
  
• Allelopathic: Inhibits growth of nearby plants, affecting crops and native species.
  
• Spines/thorns: Poses physical barriers to livestock and human activities.
  
• Host for pests/pathogens: Susceptible to insects and fungi that may spread to other plants.
  
• Prolific seed production: Mature trees produce thousands of seeds annually.
  
• Persistent seed bank: Seeds remain viable for extended periods.
  
• Tolerant of mutilation: Can resprout after cutting or damage.

Low Risk Traits:

• Not shade-tolerant: Requires open, sunny conditions for establishment.
  
• Not toxic to animals or humans: Safe for livestock and humans.
  
• Not adapted for wind dispersal: Seeds lack mechanisms for long-distance wind spread.
  
• Controlled by herbicides: Effective chemical control methods exist.