Family: Poaceae
Urochloa ramosa (browntop millet, dixie signalgrass) is a grass native to tropical Asia and Africa but has naturalized in the southern United States since its introduction in the early 20th century. It is often used as a forage crop for livestock and can provide nutritious fodder, although it can accumulate toxic levels of nitrate and should not be fed to livestock if the grass has been stressed by drought or cold conditions. This grass species is known for its ability to adapt to a range of environmental conditions, which has contributed to its widespread cultivation and use in various agricultural and ecological applications. However, it can also be considered a weed in certain agricultural settings when it grows aggressively and competes with desired crops. There is no evidence of naturalization in the Hawaiian islands of Urochloa ramosa to date.
High Risk Traits:
- Broad climate suitability
- Grows and able to spread in tropical regions
- Naturalized in Australia and North America (Mexico and SE USA), but no evidence in the Hawaiian Islands to date
- A weedy grass and minor agricultural weed reported to impact quality and yield of certain crops
- Other Urochloa species are invasive weeds
- Can accumulate toxic levels of nitrate and should not be fed to livestock if the grass has been stressed by drought or cold conditions
- Tolerates many soil types
- Reproduces by seeds
- Annual/perennial life cycle (able to reach maturity in one growing season)
- Seeds dispersed by cultivation, possibly water, and potentially by animals or as a crop contaminant
- Seeds may form a persistent seed bank
Low Risk Traits:
- A domesticated crop with cultivated forms that have greatly reduced dispersibility
- Weedy impacts appear to be restricted to certain crops
- Unarmed (no spines, thorns, or burrs)
- Valued pasture grass and source of feed for birds
- Grows best in high light environments (dense shade may inhibit spread)
- Herbicides, mowing and potentially fire may provide effective control
