Indicator 3.1a: Scale and impact of agents and processes affecting forest health and vitality (2024) - Supporting information

Vertebrate herbivore pests

For this update, a national approach was taken to assess the occurrence of five vertebrate herbivore pest species—rabbit (Oryctolagus cuniculus), feral pig (Sus scrofa), feral deer (Cervidae sp.), feral goat (Capra hircus) and feral horse (Equus caballus)—in forests. Area-based records for each species were extracted from the national pest animal spatial dataset (West 2011). These spatial records, which identifies the presence of pests within 10 km-sized tiles, were intersected with the Tenure of Australia’s Forests (2018) spatial dataset of national land tenure types and forest categories (ABARES 2018) to derive the area of occurrence of each pest species in commercial plantations, native forest on other Crown land, multiple-use public native forest, and native forest in nature conservation reserves. The Tenure of Australia’s Forests (2023) spatial dataset (ABARES 2023) was not available at the time of analysis.

Commercial plantations comprise hardwood or softwood plantations managed commercially to supply logs to wood-processing industries for the manufacture of wood products.

Data and information on the tenure of Australia’s forest can be found in Indicator 1.1a.ii Forest area by tenure.

Insect pests and pathogens

Data on the scale and impact of insect pests and pathogens in forests were collated from responses provided by each state and territory through their representatives on the Forest Health and Biosecurity Committee of the Australian Forest Products Association.

Ratings that describe the scale and impact are as used previously in Australia’s State of the Forests Report 2018, with slight amendments:

• Restricted scale: occurs in 25% of the area of forest being reported
• Widespread scale: occurs in 25% of the area of forest being reported
• Minimal impact: damage events are of limited duration and/or severity enabling the forest to recover with minimal departures to composition, natural mortality rates and productivity.
• Adverse impact: damage events are protracted or recurrent and/or of sufficient severity to cause a change in composition, sharp or sustained increase in mortality rates above natural rates, and/or a sustained decline in productivity.

Ratings that describe the extent of the control programs used as management response are unchanged from those used previously:

• 0: no control
• 1: ad hoc (unplanned) control
• 2: Limited, targeted control
• 3: Widespread, targeted control
• 4: Widespread, general
• 5: Eradication.

Weeds

For this update, a national approach was taken to assess the occurrence of the 24 weed species most commonly reported by jurisdictions in Australia’s State of the Forests Report 2018. Point-based records for these weeds lodged between 1990 and 2019 were extracted from the Australasian Virtual Herbarium compiled for the national prioritisation of Australian plants affected by the 2019-20 bushfire season (Gallagher 2020). A 10 km buffer was applied to the point locations for each record, which were then intersected with the Tenure of Australia’s Forests (2018) spatial dataset of national land tenure types and forest categories (ABARES 2018) to derive an area of occurrence of each weed species in commercial plantations, multiple-use public native forest, and native forest in nature conservation reserves. The Tenure of Australia’s Forests (2023) spatial dataset (ABARES 2023) was not available at the time of analysis.

Commercial plantations comprise hardwood or softwood plantations managed commercially to supply logs to wood-processing industries for the manufacture of wood products.

Data and information on the tenure of Australia’s forest can be found in Indicator 1.1a.ii Forest area by tenure.

Gallagher RV (2020). National prioritisation of Australian plants affected by the 2019-2020 bushfire season, Report to the Commonwealth Department of Agriculture, Water and Environment. Department of Agriculture, Water and Environment, Canberra.

West P (2011). National mapping of the abundance of established, new and emerging pest animals to improve decision-making and the assessment of government investment programs. Stage 1: Pest Animals, Final Report to ABARES, NSW Department of Primary Industries and Invasive Animals CRC, Canberra. pestsmart.org.au/tags/control/