South East Arafura Catchment Rangers spraying Hyptis suaveolens along the Central Arnhem Road – before (left) and after spraying.

South East Arafura Catchment Rangers spraying Hyptis suaveolens along the Central Arnhem Road – before (left) and after spraying.

South East Arafura Catchment Rangers spraying Hyptis suaveolens along the Central Arnhem Road – before (left) and after spraying.

South East Arafura Catchment Rangers spraying Hyptis suaveolens along the Central Arnhem Road – before (left) and after spraying.

Donydji rangers spraying and hand-pulling Caltrop (Tribulus cistoides/terrestris). Caltrop rapidly invades denuded areas and the seed carrying burrs are spread by animals and vehicles.

Donydji rangers spraying and hand-pulling Caltrop (Tribulus cistoides/terrestris). Caltrop rapidly invades denuded areas and the seed carrying burrs are spread by animals and vehicles.

Donydji rangers spraying and hand-pulling Caltrop (Tribulus cistoides/terrestris). Caltrop rapidly invades denuded areas and the seed carrying burrs are spread by animals and vehicles.

Donydji rangers spraying and hand-pulling Caltrop (Tribulus cistoides/terrestris). Caltrop rapidly invades denuded areas and the seed carrying burrs are spread by animals and vehicles.

Women rangers removing weeds at Djapitjapin waterhole

Women rangers removing weeds at Djapitjapin waterhole

Rangers undertaking weed control with a spray unit at Dhabla on the barge landing road.

Rangers undertaking weed control with a spray unit at Dhabla on the barge landing road.

It’s a constant battle for rangers to control Gamba Grass. These plants were discovered in a contractor’s yard and destroyed.

It’s a constant battle for rangers to control Gamba Grass. These plants were discovered in a contractor’s yard and destroyed.

Rangers filling herbicide tanks for the aerial control of Mimosa and Olive Hymenachne.

Rangers filling herbicide tanks for the aerial control of Mimosa and Olive Hymenachne.

Women rangers engaging in weed identification and undertaking Mission grass management in Ramingining

Women rangers engaging in weed identification and undertaking Mission grass management in Ramingining

Rangers manually removing Candle bush (Senna alata) at Garpal on the edge of the Arafura Swamp. Candle bush can invade native bushland in wetter areas, forming dense thickets.

Rangers manually removing Candle bush (Senna alata) at Garpal on the edge of the Arafura Swamp. Candle bush can invade native bushland in wetter areas, forming dense thickets.

Women rangers engaging in weed identification and undertaking Mission grass management in Ramingining

Women rangers engaging in weed identification and undertaking Mission grass management in Ramingining

May 15, 2019

Mimosa (Mimosa pigra) and Olive Hymenachme (Hymenachne amplexicaulis) are the most serious environmental weeds found in the Arafura Swamp region. Both are wetland invaders with the potential to irrevocably change the swamp’s ecosystem. While Mimosa is currently under control, Olive Hymenachme continues to spread, threatening not only wildlife but traditional economies based on the wetlands.

Upland areas are threatened by Mission grass (Cenchrus polystachios), Grader grass (Themeda quadrivalvis) and Gamba grass (Andropogon gayanus). These introduced grasses out-compete native grasses and increase fuel loads, resulting in more intense fires and the loss of fire-sensitive understory species, the death of mature trees and general loss of biodiversity. By altering fire regimes invasive grasses have the potential to disrupt lucrative and environmentally important savanna carbon projects. Through vigilance and priority eradication of outbreaks along roads ASRAC Rangers have to-date managed to control these grassy weeds.