Impacts of climate change on high priority fruit fly species in Australia

projected to occur in central Queensland, Western Australia, and the Northern Territory, although model extrapolation occurs under several climate scenarios (S1 File). Comparing the distribution of suitable habitat for this fly with that of its major host crops indicates that crops grown in the Top End of the Northern Territory, and in eastern Australia from Cape York to New South Wales, may continue to be at risk until at least 2070. Other major host-plant growing regions in the south and west of the continent will also remain suit- able for this species until 2070 (S1 File). Bactrocera kraussi. For the baseline period, suitable habitat for B. kraussi is projected to have occurred across the northern tip of Australia and northeast Queensland, as far south as Townsville (S1 File). Precipitation of the wettest quarter (75.19%) had the highest contribution to the model of B. kraussi (S1 File). There is consensus across the six scenarios that the geographic extent of climatically suitable habitat may increase slightly (S1 File), although this is still confined to the Wet Tropics and far north of the continent. In addition, little extrapolation to novel conditions occurs (S1 File). Horticultural production regions in northeast Queensland may remain suitable for this species by 2070, although production regions in the south are likely to remain unsuitable (S1 File). Bactrocera musae. For the baseline period, suitable habitat for B. musae extended from the Torres Strait Islands through to the Wet Tropics (S1 File). The most important variable in

the model for B. musae was precipitation of the wettest quarter (78.7%) (S1 File). Suitable habitat for this species is projected to remain restricted to the Wet Tropics and northern–most regions of the country under the climate scenarios. While there is consensus across the six climate scenarios, less confidence can be placed in projections to the north-west (S1 File). B. musae mainly attacks Musa × paradisiaca (banana), the production areas for which are located primarily in tropical and subtropical regions of the continent (S1 File). The major commercial growing region in the Wet Tropics is projected to remain climatically suitable for this species until at least 2070 (S1 File). Bactrocera neohumeralis. Suitable habitat for this species during the baseline is projected to have been mostly confined to the Torres Strait Islands, eastern Queensland, and north east- ern NSW south to Wollongong (S1 File). Precipitation of the wettest month (47.4%) contrib- uted most to the model for B. neohumeralis (S1 File). As the century progresses, considerable differences in suitable habitat are projected across the six scenarios. For example, under the CanESM2 scenario, ~ one quarter of current suitable habitat is projected to be lost by 2030, although by 2070, range expansions are projected to exceed losses (S1 File). Similarly, under the hot, very dry scenario simulated by GFDL-ESM2M, total range size may decline by 2030, mostly due to contractions in the south and east, although limited gains in habitat may occur in northern Australia (S1 File). There is

consensus in projections of suitability across the north tips of the continent, however MESS maps indicate that Maxent has extrapolated suitability in these regions. In contrast, greater confidence can be placed in projections of consensus along the east coast (S1 File). Production regions in eastern Queensland and north-eastern NSW will likely remain suit- able for this species until at least 2070, although there is substantial uncertainty across the cli- mate scenarios. In contrast, regions along the NSW-Victorian border and further south are projected to remain unsuitable for B. neohumeralis (S1 File). Bactrocera tryoni. Highly suitable habitat for B. tryoni is projected to have occurred in south-western Western Australia, south-eastern South Australia, Victoria, and eastern Austra- lia from Cape York to NSW in the baseline period (S1 File). Coastal zones in northern West- ern Australia, the Northern Territory and the eastern half of Tasmania have moderate Impacts of climate change on high priority fruit fly species in Australia PLOS ONE | https://doi.org/10.1371/journal.pone.0213820 February 13, 2020 8 / 19