Predicting potential occurrence of Adelges tsugae (Homoptera: Adelgidae) on a global scale under climate change scenarios using maximum entropy model

Abstract

Invasive alien species pose grave threats to natural ecosystems and human society. The hemlock woolly adelgid (HWA; Adelges tsugae Annand) is an invasive alien species in several countries, causing severe damage to forest mainly composed of hemlock and spruce. This study employed a maximum entropy model to predict the global potential occurrence areas of HWA based on worldwide HWA occurrence data and four bioclimatic variables: mean diurnal range (BIO2), mean temperature of the wettest quarter (BIO8), mean temperature of the coldest quarter (BIO11), and annual precipitation (BIO12). Future climate change scenarios were used to assess the effects of climate change on HWA distribution. The developed model showed good predictive performance for HWA occurrence (AUC:0.992, F1 score: 0.876), with BIO11 being the most influential factor for HWA occurrence, followed by BIO12. The model identified high-risk areas in North America and eastern Asia including Korea, the Himalayan regions, central and western Europe, Oceania including southeastern Australia and New Zealand, and western part of South America. Additionally, most distribution areas of hemlock trees were in areas where HWA could potentially occur. According to climate change, the model predicted a northward shift in the average latitude of the predicted potential distribution areas showing that the range of HWA may potentially expand even into subarctic regions, where the occurrence probability is currently lower than that of temperate regions. The findings of this study provide valuable insights into the potential occurrence and invasion risk of HWA in current and future climates and emphasize the importance of proactive measures to monitor and manage its spread.