An aerial survey was carried out last month to assess the treatment effectiveness of May and August treatment cycles on Parkinsonia populations on Roy Hill Station.
The survey included transect runs of ephemeral waterways and the adjoining landscape to check for unrecorded plants in areas that had previously shown no presence.
The Pilbara Corridors Project has invested in managing Parkinsonia, a weed of national significance, since 2013. The program involves Pilbara Mesquite Management Committee (PMMC) as the delivery organisation, treating known infestations in the lower and upper Fortescue catchment.
Pilbara Corridors Program Manager Ian Cotton said 67, 713 plants were treated this year.
“The treatment success rate was evident on the aerial survey, with 224 live Parkinsonia sighted outside of the treatment area,” he said.
“The new sightings will be treated as part of the next tranche early in 2017.”
The objective of the project is to treat and contain infestations, removing adult plants to prevent them from producing seeds.
The treated populations are then monitored over time to ensure the treatment has been effective and that any emergent seedlings from seed beds are identified and also treated.
Mr Cotton said Parkinsonia poses a threat to biodiversity—it is a dominant weed competing with endemic vegetation.
“In collaboration with stakeholders, we aim to remove Parkinsonia from the Fortescue catchment and keep it out of the adjoining Fortescue Marsh, a nationally significant wetland,” he said.