Evolution of the recent habitat suitability area of Aedes albopictus in the extended Mediterranean area due to land-use and climate change.

The Asian tiger mosquito, Aedes albopictus, is one of the world's most invasive species and is responsible for the transmission of several vector-borne diseases, including chikungunya, dengue, and Zika. Aedes albopictus has been established in southern Europe since the 1990s and has been spreading to other regions in recent years. The present study examines changes in the habitat suitability of Aedes albopictus over the period 2000-2020 using a multi-model ensemble (MME) of maximum entropy (MaxEnt) models. An initial set of 38 climatic and 14 land-use predictors was considered for model setup. The model was built using Aedes albopictus distribution data for 2020. We included 19 bioclimatic variables, absolute humidity, and 18 extreme climate variables which are tailored to species specific thresholds based on expert knowledge. By means of statistical methods, predictor selection was performed. To assign changes to climate or land-use, we ran all habitat suitability models on varying climate with constant and varying land-use. Differences between both approaches indicate causes of change. Land-use changes are an important factor until 2015, contributing at least as much as climate change to changes in the habitat suitability area of Aedes albopictus (HSA). In the following years, changes in the HSA are mainly shaped by climate change. In 2020, the MME shows an average 4.5 % increase in HSA compared to 2000, with decreasing habitat suitability in the south and increasing suitability in the north. Land use change accounts for 16-51 % of HSA change, but only 3.3 % of land use change is spatially consistent across the MME. In contrast, changes in the HSA due to climate change has a spatial consistency of 54.2 % across the MME. The overall increase in HSA between 2000 and 2020 also increases the risk of vector-borne disease infections, but land-use changes can counteract some of the climate-induced changes.