Diversity and Spatiotemporal Atlas of Ticks in the Beijing-Tianjin-Hebei Urban Agglomeration Based on the MaxEnt...

This study aims to delineate the present and projected suitable habitats for four dominant tick species in the Beijing-Tianjin-Hebei (BTH) region, providing a spatial basis for targeted tick-borne disease surveillance.

We systematically reviewed the published literature and the Global Biodiversity Information Facility (GBIF) to compile tick occurrence records in the BTH region. A total of 167 geo-referenced occurrence records with verified coordinates were obtained for four dominant species: Haemaphysalis longicornis, Haemaphysalis concinna, Dermacentor silvarum, and Ixodes persulcatus. The MaxEnt model was applied with bioclimatic variables (WorldClim, 2.5 arc-min), elevation, slope, aspect, and NDVI. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) for within-species comparisons, complemented by the True Skill Statistic (TSS), Cohen's kappa, and omission rate. Future projections (2021-2040, 2041-2060, 2061-2080, 2081-2100) were made under the SSP245 scenario using only climate variables, as the NDVI and topographic variables cannot be reliably forecast.

The four dominant tick species showed distinct distribution patterns: Hae. longicornis was widely distributed across the BTH region, whereas Hae. concinna, D. silvarum, and I. persulcatus were mainly found in the northern and northwestern mountainous areas. The primary environmental drivers were temperature, elevation, and the NDVI. MaxEnt models achieved good predictive performance (test AUC: 0.86-0.91; TSS: 0.72-0.88). Under future climate scenarios, suitable habitat centroids were projected to shift northwestward for Hae. longicornis (~57.6 km), D. silvarum (~71.1 km), and I. persulcatus (~50.0 km), and northeastward for Hae. concinna (~63.0 km) by 2081-2100.

In this study, we identified current and future high-risk areas for four dominant tick species in the BTH region, providing a reproducible foundation for surveillance. Future projections should be interpreted with caution as they only account for climatic changes.