Chuanji Yong, Michelle Ward, James Watson, April E. Reside, Stephen Van leeuwen, Sarah Legge, William L. Geary, Mark Lintermans, Mark Kennard, Stephanie Stuart

1. Budgeting for biodiversity conservation requires realistic estimates of the costs of threat abatement. However, data on the costs of managing threats to biodiversity is often unavailable or unable to be extrapolated across relevant locations and scales due to a lack of transparency and consistency in how it was collated. Conservation expenditure largely occurs without a priori estimates costs across broad scales and is not recorded in ways that can inform future budgets nor the comparison of action cost-effectiveness.
2. We provide transparent, broadly applicable cost models for 18 Threat Abatement Strategies aimed at managing the processes threatening biodiversity across the Australian continent. We define the actions required to implement each strategy and use a consistent structure to classify costs into components of labour, travel, consumables and equipment. We drew upon expert knowledge and literature to parameterise and apply each model, estimating the implementation cost of each strategy across Australia, accounting for spatial variables such as threats, terrain, and travel distance.
3. The baseline cost estimates generated by the models for threat abatement strategies varied considerably between strategies and across Australia, ranging from $24 - $0.88m per km2/year ($0.24 - $8.8k per ha/year). Across all strategies, Labour made up most of the action costs (49%), followed by Consumables (37%), Travel (13%) and Equipment (2%). A Monte Carlo simulation indicated that threat abatement strategy costs had on average an upper and lower bound of +44% and -33% of the baseline cost.
4. Policy Implications - We provide a consistent and transparent approach to budgeting for threat abatement strategies, aiming to improve conservation planning processes, outcomes and reporting requirements across Australia. Understanding the budget required to achieve threat management outcomes can aid revenue-raising and target setting. The models, cost layers and estimates we generate provide the basis for a nationally consistent approach for estimating and recording the cost of biodiversity management strategies, which should be continually improved and updated over time.