Predicting the potential global distribution of Ixodes pacificus under climate change

in the western United States [1, 2]. Since 1950, the historical geographic range of I. pacificus has been expanding due to human activities, climate, and land utilization. However, its distribution range has been relatively stable in the past 20 years, and it is possible that the region where I. pacificus is now found has almost reached the level of its basic ecological niche [3]. Since the last century, with the rapid increase of the global population and the increasing frequency of human economic activities, the global climate has undergone significant changes [4]. According to the Sixth Assessment Report of the United Nations Intergovernmental Panel on Climate Change (IPCCAR6), global land and ocean temperatures have increased by 1.09˚ C between 1901 and 2020. Global climate change has a serious impact on the global natural ecosystem, changing the geographical and natural environment, destroying biodiversity, and even threatening human life and health [5, 6]. Among them, the distribution and quantity of vectors are easily affected by temperature, and the propagation and spread of pathogens in their bodies are also affected by climate factors [7]. Global warming and changes in precipita- tion provide environmental advantages for the invasion and colonization of species. It is possi- ble for I. pacificus to spill over and colonize, which will pose a huge threat to local human and animal health and public health. Ecological niche modeling (ENM) is a mathematical model that estimates the actual and

potential distribution of target species by quantifying the relationship between the distribution data of species and the corresponding environmental variables [8]. ENM can be divided into correlative models (MaxEnt, BIOCLIM, HABITAT and DOMAIN) and mechanistic models (BOMAIN and CLIMEX) according to basic principles [9, 10]. MaxEnt is a species distribu- tion prediction model based on the theory of maximum entropy. It can calculate the contribu- tion rate of environmental variables using the knife cutting method and evaluate its own model using the area under ROC curve (AUC). It is a model with more extensive application and better prediction ability among species distribution models [11, 12]. Based on the historical distribution data and climate data of I. pacificus, the maximum entropy model (MaxEnt) was used to estimate its global distribution range under historical cli- mate scenarios and different future climate scenarios, and the influence of environmental cli- mate factors on the change of distribution range was analyzed. Materials and methods Distribution data collection and processing of I. pacificus The occurrence points of I. pacificus were acquired mainly from the Global Biodiversity Infor- mation Facility (GBIF; GBIF.org (29 March 2024) GBIF Occurrence Download https://doi. org/10.15468/dl.3wrhb5) database and related research literature of CNKI, Web of Science, PubMed, MEDLINE, Embase, and other databases. The time range is from 1950 to 2024. Screen the field survey records of I. pacificus and select the latitude and longitude information

of the collection points (S1 File). Via OpenStreeMap (https://osm.openmaptiles.org/, accessed on 31 March 2024), the accuracy of coordinate points were checked and points with apparent errors in geographical coordinates were removed. To avoid overfitting, use ENMtools software to remove redundant data within the same grid. All sample point data were saved in a CSV file, which contained three columns, i.e., species name, longtitude and latitude coordinate values. Software and geographic data Steven J. Phillips, Miroslav Dudı´k, Robert E. Schapire. [Internet] Maxent software for model- ing species niches and distributions (Version 3.4.1). Available from url: http:// biodiversityinformatics.amnh.org/open_source/maxent/. Accessed on 1 March 2024. ArcGIS PLOS ONE Prediction of the distribution of Ixodes pacificus PLOS ONE | https://doi.org/10.1371/journal.pone.0309367 August 27, 2024 2 / 18 Competing interests: The authors have declared that no competing interests exist.