Predicting the distribution of Ixodes ricinus in Europe: Integrating microclimatic factors into ecological niche models

Ixodes ricinus , commonly known as the castor bean tick and sheep tick, is a significant vector of various diseases such as tick-borne encephalitis and Lyme borreliosis. Due to climate change, the distribution and activity of I. ricinus are expected to increase, leading to a rise in diseases transmitted by this species. Most of the distribution models and ecological niche models utilize macroclimate datasets such as Worldclim or CHELSA in order to map the distribution of disease transmitting ticks. However, microclimatic factors are crucial for the activity and survival of small arthropods. In this study, an ecological niche modeling approach was followed in order to assess the climatic suitability of I. ricinus using both microclimatic and macroclimatic parameters. A Microclimate model was built combining parameters from Soiltemp and Wordclim databases while a Macroclimate model was built with the CHELSA dataset. Also future suitabilities were projected using the Macroclimate model under SSP370 and SSP585 scenarios. Both Macroclimate and Microclimate models showed similar distributions, confirming the current distribution of I. ricinus . The most important climatic factors were seasonality, annual temperature range, humidity and precipitation. Future projections suggest a significant expansion in northern and eastern Europe with notable declines in southern regions.