Estimating the impact of invasive pests and diseases on ecosystem services: Modelling carbon sequestration loss due to myrtle rust (Austropuccinia psidii exotic strains) in Australia

Biosecurity systems are routinely valued based on the impacts of invasive pests and diseases on agriculture and industry, but less so on the impacts to biodiversity and ecosystem services. We estimated the potential reduction of carbon sequestration in Australia due to exotic strains of myrtle rust ( Austropuccinia psidii , also known as Puccinia psidii , guava rust, or ōhi’a rust). We modelled the carbon sequestered by woody plants susceptible to myrtle rust and used previously known myrtle rust damage estimates to susceptible plant species and the valuation of carbon sequestration in Australia to estimate the potential monetary impact. We found that myrtle rust could cause up to a 1.6% (95% CI: 1.3–2.0%) annual reduction in national carbon sequestration if it were to spread across all climatically suitable areas in Australia, resulting in an estimated value loss of over $340 million AUD (over $220 million USD) per year. Invasive species can reinforce the negative impacts of climate change. Our work supports the need to integrate invasive species management and biosecurity decision-making with climate change resilience initiatives such as reforestation efforts. Our method can also be extended to systematically compile the potential impacts and costs of other invasive plant pests to the environment and ecosystem services.