Forecasting the potential distribution of the invasive vegetable leafminer using "top-down" and "bottom-up" models

The vegetable leafminer, Liriomyza sativae, is an internationally significant pest of vegetable and flower crops, that was detected for the first time on the Australian mainland in 2015. Due to the early stage of its invasion in Australia, it is unclear how climatic conditions are likely to support and potentially restrict the distribution of L. sativae as it expands into a novel range and threatens agricultural production regions. Here we predicted the future establishment potential of L. sativae in Australia, using both a novel bottom-up process-based model and a popular top-down correlative species distribution model (SDM), leveraging the unique strengths of each approach. Newly compiled global distribution data spanning 42 countries was used to validate the process-based model of establishment potential based on intrinsic population growth rates, as well as parameterise the correlative SDM. Both modelling approaches successfully captured the international distribution of L. sativae based on environmental variables and predicted the high suitability of non-occupied ranges, including northern regions of Australia. The largely unfilled climatic niche available to L. sativae in Australia demonstrates the early stage of its Australian invasion, and highlights locations where important vegetable and nursery production regions in Australia are highly vulnerable to L. sativae establishment.