Prioritisation

2016/17

At the beginning of the project in 2016, a transparent prioritisation framework was devised and approved by the Trust’s Biodiversity and Green Corridors Subcommittee. It is based on a matrix assessment system that involves: 1) initial screening steps to identify eligible weeds, 2) an assessment of the threat each weed poses to natural ecosystems, 3)  the feasibility of undertaking a biocontrol project for each weed using the most promising candidate biocontrol agent, and 4) the likelihood of the selected agent being successful at controlling the weed if released in a new environment. The framework was applied to generate a justified, priority list of biocontrol weed targets.

Schematic of prioritisation framework.

The prioritisation framework was applied to generate a justified, priority list of biocontrol weed targets. Of the 67 eligible weeds identified and assessed, it was deemed unfeasible or unnecessary, for a range of reasons, to undertake a biocontrol project for 49 weeds. The priority list comprised the remaining 18 weeds, each allocated to a cell in a matrix of weed threat versus biocontrol prospects.

Results from the 2016 prioritisation: Weeds classified according to weed threat and biocontrol prospects with the most promising candidate biocontrol agent. Number in parentheses corresponds to the Weed Risk Assessment score for the weed. Weeds in the yellow cells are considered first priority, and those in the orange cells are second priority.

 

Considering the first and second priority weeds identified and resources available in 2017, the Trust’s Biodiversity and Green Corridors Subcommittee selected five weeds for initial investment for the period July 2017 to October 2021: Balloon vine (Cardiospermum grandiflorum), broad-leaved pepper tree (Schinus terebinthifolius), leaf cactus (Pereskia aculeata), sea spurge (Euphorbia paralias) and yellow bells (Tecoma stans).

2018/19

Following consultation with the Trust’s Biodiversity and Green Corridors Sub-Committee, the Trust agreed to become a partner in a national proposal on weed biocontrol, led by AgriFutures Australia, that was submitted in November 2018 to Round 4 of the Australian Government program Rural Research and Development for Profit (RRnD4P; administered by the Department of Agriculture, Water and the Environment [DAWE]). The Trust pledged cash to the proposal, specifically to contribute to biocontrol research on the following weed species: African boxthorn (Lycium ferocissimum) led by CSIRO; African lovegrass (Eragrostis curvula) and Hudson pear (Cylindropuntia pallida (rosea) led by NSW DPI; and giant rat’s tail grass (Sporobolus natalensis) led by Queensland Department of Agriculture and Fisheries). These four weeds are comprised in the list of widespread or emerging environmental weeds in NSW that was used as a first screening step as part of the prioritisation process conducted in 2016.

The RRnD4P proposal was successful and the contract between DAWE and AgriFutures Australia was signed in June 2019. Delays however, have been encountered in finalising subcontracts between AgriFutures Australia and the different research providers. The project’s final report will be submitted in mid-Mach 2022.

2019/20

In 2019 a review and update of the prioritisation of weed targets/promising agents undertaken in 2016 was performed. Options for investment in a second most promising agent for selected weeds, and in recently approved and released agents in Australia that are relevant for NSW were also outlined to assist decision making by the Trust’s Biodiversity and Green Corridors Subcommittee.

Approach taken for the review and update the prioritisation process first undertaken in 2016.

Of the 72 eligible weeds assessed, biocontrol was deemed unfeasible or unnecessary for 50. The remaining 22 weeds were classified according to biocontrol feasibility and likelihood of success to generate a ranking for biocontrol prospects. Each weed was then allocated to a cell in the matrix ‘Biocontrol prospects X Weed threat’.

Results from the 2019 prioritisation: Weeds classified according to weed threat and biocontrol prospects with the most promising candidate biocontrol agent. Number in parentheses corresponds to the Weed Risk Assessment score for the weed. Weeds in the yellow cells are considered first priority, and those in the orange cells are second priority. Weeds with Asterix were either missed during the prioritisation process undertaken in Stage I or recent information has been found on relevant biocontrol research.

 

Following deliberations, the Trust’s Biodiversity and Green Corridors Subcommittee selected the following options for investments for the period from July 2020 to June 2023: (i) large-scale releases and evaluation of the leaf-smut fungus Kordyana brasiliensis for the biocontrol of wandering trad (Tradescantia fluminensis) in NSW, (ii)  testing of the privet lace bug Leptoypha hospita, a potential biocontrol agent for small-leaf privet (Ligustrum sinense), on the sole native Ligustrum species in Australia (~1 year), (iii) host-specificity testing of the root-feeding weevil Cyphocleonus trisulcatus, a potential biocontrol agent for ox-eye daisy (Leucanthemum vulgare).