Potential global distribution of Aleurocanthus woglumi considering climate change and irrigation

although in specific regions within these states, the insect will probably experience heat stress but continue to be present at low levels. In South America, a slight increase in climate suitability is projected for A. woglumi in the near future (Fig 2B). Major decreases in areas modelled as suitable are observed in the eastern part of Brazil but decreases are also visible in portions of the Amazon basin as well as in states of central and northern Brazil (Figs 2A, S5A and S5B). According to climate projections, by mid-century increases in temperature and associated decreases in soil water are projected to lead to gradual replacement of tropical forest by savanna in eastern Amazonia, as changes in precipitation patterns and the disappearance of glaciers are projected to significantly affect water availability [51,71]. These changes would likely be accompanied by a rise in dry and heat stress levels and the productivity of some important crops is projected to decrease [50]. As it is projected for other tropical regions, water stress, increased temperature and the impact of an increased incidence and abundance of old and new invasive pests, diseases and weeds will lead to agricultural decline [23]. In Africa, a slight decrease in the climatically suitable area is projected, but the range of eco- climatic values remains relatively high. Some areas in northern Tunisia and Morocco with temperate climate are projected to remain climatically suitable for A. woglumi (Figs 2A, S6A and S6B). In areas in central and southern Africa such as Zambia, Zimbabwe, and neighboring

countries there is a range contraction, and the areas where the range expands are restricted to the northern and eastern parts of Africa (Fig 2B). In Europe, the potential distribution of A. woglumi expands northward under the future cli- mate scenarios (Fig 2B). Due to temperature increases, the cold limitations in some areas could be overcome under future climate scenarios. At the same time, drought-affected regions are projected to increase in extent, especially in the Mediterranean Basin [50], and in combina- tion with the temperature increases are projected to limit wide dispersal of the pest (Figs 2A, S7A and S7B). In Oceania, the future climate simulations project that areas with EI>0 for A. woglumi will expand slightly (Fig 2B). In Australia, the model projects a progressive contraction of suitable regions, especially in the south and north-west. In New Zealand, Northland and parts of East Cape and the Bay of Plenty become favourable under the future climate projections, potentially exposing citrus and other horticultural industries to A. woglumi invasion risks (Figs 2A, S8A and S8B). The use of a spatially explicit irrigation scenario provides a highly effective means of esti- mating the potential distribution of agricultural hosts and pests. It avoids the problem of adopting biologically implausible soil moisture parameters to “explain” the presence of a spe- cies in xeric environments, with the subsequent problem of then modeling all locations with a similar xeric climate as being suitable, severely diminishing model specificity.

Environmental suitability simulations for invasive species under current and future scenar- ios provide a strategic tool for risk managers to gain foresight into emerging pest invasion pat- terns, enabling them to develop effective control and surveillance strategies. Hence, the model presented in this study for A. woglumi can be used to estimate current and emerging risk areas to develop better procedures for early detection and improve resource allocation for adaptive management under climate change. The irreducible uncertainties in forecasting the emission patterns of greenhouse gases translate into substantial uncertainties in the extent and rate of change in climates. Model sensitivity analyses such as those we have performed should guide the development of contingency planning on the basis that the models may be right, but equally, they may under- or over-estimate the climatic changes. A prudent contingency plan will include a solid investment in surveillance, identifying and monitoring lead indicator PLOS ONE Potential global distribution of Aleurocanthus woglumi PLOS ONE | https://doi.org/10.1371/journal.pone.0261626 December 20, 2021 11 / 18