Northward shift in temperature sum isoclines may favour Ips typographus outbreaks in European Russia

• Published in: Agricultural and Forest Entomology
• Main Authors: Romashkin, Ivan, Neuvonen, Seppo, Tikkanen, Olli-Pekka
• Other Authors: School of Forest Sciences, activities
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Wiley 2021
• Subjects: climate change; ips typographus; Norway spruce; outbreaks; voltinism; Norway; taiga
• Online Access: https://erepo.uef.fi/handle/123456789/24369

1. As the development of the eight‐toothed spruce bark beetle Ips typographus is temperature‐dependent, climate change may encourage development of its additional generations per year and facilitate mass outbreaks further north than previously known. 2. The aim of the study was to analyse historical changes in effective temperature sums (ETSs) and early season swarming weather for I. typographus in different forest zones of European Russia between 1960 and 2016. The difference in ETSs was analysed with linear regression using daily temperature data from the 30 meteorological stations. Historical data regarding the location of I. typographus outbreaks were examined and changes in their distribution during the entire study period were analysed. 3. There was a substantial increase in ETSs, especially in the latter half of the study period. Increased ETSs coincided with more favourable conditions for swarming of I. typographus. Areas with favourable ETSs for the complete development of bivoltine populations of I. typographus (>1500 DD) shifted northwards on average 450 km during the entire study period. 4. The northward shift of ETSs may enhance the transition from univoltine to bivoltine life cycles of I. typographus in the south and middle taiga and from bivoltine to trivoltine life cycles in conifer‐broadleaf forests. final draft peerReviewed