Predicting the potential global distribution of Ixodes pacificus under climate change

addition to directly affecting the survival of ticks, climate conditions also affect the growth rate of ticks in immature life stages and seasonal behavior of searching for hosts [18]. Related stud- ies on modeling non biological and biological factors related to the distribution of I. pacificus have shown that temperature and precipitation in the cold season are important factors affect- ing the environmental suitability of I. pacificus, with warm and humid climate conditions in winter being the most suitable [3, 19]. The results are basically consistent with the results of this study. The results of this study show that the main climate variables affecting the distribu- tion of I. pacificus are Prec1, Tmin2, Bio3, Prec7 and Elev, among which Tmin2 and Prec1 contribute the most. When the lowest temperature in the cold season is between -45.1–7.9˚C, it may be more suitable for the survival of I. pacificus. When the winter precipitation is between 70-626mm, it is more suitable for the survival of I. pacificus, and the most suitable precipitation is 300mm. The results of this study showed that the distribution range of I. pacificus showed a decreas- ing trend. Eisen et al. (2016) found that the distribution of I. pacificus has been relatively stable over the past two decades, which may indicate that the actual ecological niche of the current region of the I. pacificus is close to the range of its basic ecological niche (all countries and regions suitable for the survival of I. pacificus based on local environmental and climatic condi-

tions). The basic niche may be wider than it actually is, but biological factors such as host migration or lack of hosts slow the spread of the tick range [19, 20]. Porter et al. (2021) used the future climate prediction (2050, RCP8.5) and found that about 30% of the habitat range of Fig 9. The potential distribution of suitable areas for I. pacificus around the world under the climatic conditions of SSP1-2.6. (a)2021-2040; (b) 2041-2060; (c)2061-2080; (d)2081-2100. Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. https://doi.org/10.1371/journal.pone.0309367.g009 PLOS ONE Prediction of the distribution of Ixodes pacificus PLOS ONE | https://doi.org/10.1371/journal.pone.0309367 August 27, 2024 11 / 18