INVASIVE PLANTS

The Cook Shire local government area is host to a wide variety of invasive plants, too numerous in number to list or target individually. To ensure that management strategies and resources are allocated to control species with the highest potential to disrupt natural and agricultural systems a local group, open to all stakeholders and known as the Invasive Plants and Animals Advisory Committee, has developed a list of priority invasive plants. This list is defined within the Cook Shire Local Government Area Biosecurity Plan 2022-2026 and listed below. For further information about these species see below:

Sicklepod (Senna obtusifolia)

Grader grass (Themeda quadrivalvis)

Gamba grass (Andropogon gayanus)

Rat’s tail grasses (Sporobolus spp.)

Rubber vine (Cryptostegia grandiflora)

Thatch grass (Hyparrhenia rufa) 

Salvinia (Salvinia molesta)

Pond apple (Annona glabra)

Hymenachne (Hymenachne amplexicaulis)

Mission grass (Cenchrus polystachios) 

Lantana (Lantana camara)

Calotrope (Calotropis procera)

Bellyache bush (Jatropha gossypiifolia)

Navua sedge (Cyperus aromaticus)

Identification of invasive plants is a component of surveillance, one of Council’s most important responsibilities. If you have found a plant that you believe may be invasive Council encourages you to contact our Biosecurity team on 4082 0500. Our staff are always available to assist with identification. In circumstances where we are unable to identify specimens a sample will be sent to the Queensland Herbarium for assessment by professional botanists. Alternately, you can send a sample to the Queensland Herbarium yourself. This is a free service and instructions on how to collect, preserve and send a specimen can be found at the Queensland Herbarium’s website. Should your sample prove to be an invasive species please ensure you advise Biosecurity Services so this can be recorded in our GIS database.

To assist landholders with the management of invasive plants Biosecurity Services have in place a Spray Unit Loan Program. Currently, Biosecurity Services have two 600L Quick Spray units and smaller 12 volt units available for loan. The capacity and efficiency of these units enables landholders to treat large areas while saving time and making a positive contribution to invasive plant management, enhancing broader environmental outcomes and in many cases helping adjoining properties.

To register interest landholders are required to first complete a Spray unit loan agreement form and submit in person at the Cook Shire Council administration building. Once submitted the landholder’s details will be placed on a waiting list and contact will be made as soon as a unit is available for loan. At pick-up the landholder will be required to undergo a short induction in which use of the unit will be demonstrated.

A brief summary of the spray unit loan conditions is as follows:

• The landholder is responsible for transport of the unit to and from the Council depot
• Loans are ordinarily for a maximum of 7 days only
• A $250 bond is payable prior to use*
• Each unit must be returned in the condition it is loaned, including with a full tank of unleaded fuel
• Basic details of the unit’s use must be recorded on the treatment record sheet as supplied
• Breach of the loan conditions (listed in full on the loan agreement form) may result in part or all of the bond being retained by Council

For a full list of the terms and conditions please consult the Spray unit loan agreement form. For further information regarding the Quick Spray loan program please contact Biosecurity Services on 4082 0500 or via email.

* Please note: The bond of $250.00 is to be paid in cash or card with documentary evidence confirming your Account Name, BSB and Account Number. The cash provided will be held in a trust account until the spray unit has been returned in an acceptable condition.

Invasive plants are spread through the landscape in a variety of ways including stock/animal movements, wind and water. Local observations and experience, however, indicate that the primary mechanism of spread for most species, particularly high biomass grasses, across Cape York Peninsula is along roadsides. This is suspected to be a result of seed drift from travelling vehicles and seed movement caused by roadworks and associated heavy machinery. Once a species has been translocated from an existing infestation it can quickly establish in a new area. If left untreated the infestation may expand to a point where it is beyond eradication in few seasons.

To prevent the establishment of new infestations and reduce the footprint of existing infestations Council’s Biosecurity field team works extensively across the road network on both state controlled and local roads. The focus of these works are those species designated as priority invasive plants with a specific focus on high biomass grasses. A map showing the extent of these works in 2023.

To effectively manage invasive plants across the local road network that exceeds 3,500 km in length it is necessary to have comprehensive data that details the presence and distribution of individual species. This data is gathered annually during treatment works and through specialised surveillance programs, one such example being the High Biomass Grasses Surveillance Program.

High biomass grasses (HBGs) are exotic grasses that produce vegetative matter (or biomass) several times the volume of native grasses. The increased biomass restricts the movement of native animals, reduces biodiversity and radically alters fuel loads and fire regimes. Much of our local government area is characterised by open woodlands and savannah that is particularly susceptible to the establishment of these grasses. The three HBGs of particular concern are gamba grass, thatch grass and grader grass.

To limit the spread of HBGs along roadsides the Biosecurity Services team conducts a surveillance program targeted at these species every two to three years. This program divides the road network into 1 km sections and details the presence of these species along each segment according to four values: absent (species not present), isolated (species covers < 900 m2), common (species covers 900 m2 to 4900 m2), and abundant (species covers >4900 m2).

Gamba grass is the high biomass grass of greatest concern to local agencies. Growing up to 4 metres tall it fuels intense fires that pose a threat to life and property. The species is found through peri-urban areas within the Annan-Endeavour catchment and in 2021 a group of stakeholders developed a plan to pool the resources of FNQROC councils, various local groups and state agencies in an annual 3 day treatment program. The Gamba Grass Taskforce was held in 2022 and 2023 with a further taskforce planned for 2024. Over the past two years taskforce participants have mapped gamba grass distribution within the Annan-Endeavour catchment to a high degree of accuracy, treated the species across this area resulting in a noticeable reduction in density and spread, raised local awareness of the species’ various impacts and encouraged some local landholders to actively manage gamba grass on their properties. A summary of the taskforce, drafted last year, can be found by following this link.

In addition to treatment and surveillance Council’s Biosecurity team participates in a range of research projects under the direction of scientists working for Biosecurity Queensland and CSIRO. Past projects have included assessments of alternatives for glyphosate in the treatment of gamba grass and an examination of various herbicides for pre-emergent properties that are effective against sicklepod.

More recent and ongoing projects are looking at the response of natural areas to glyphosate and the relative merits of varying revegetation strategies in addition to examining the viability of sulfometuron-methyl in the control of gamba grass, particularly as a pre-emergent.