Climate change and outbreaks of the geometrids Operophtera brumata and Epirrita autumnata in subarctic birch forest: evidence of a recent outbreak range expansion
Article first published online: 7 DEC 2007
© 2007 The Author. Journal compilation © 2007 British Ecological Society
Journal of Animal Ecology
Volume 77, Issue 2, pages 257–264, March 2008
How to Cite
Jepsen, J. U., Hagen, S. B., Ims, R. A. and Yoccoz, N. G. (2008), Climate change and outbreaks of the geometrids Operophtera brumata and Epirrita autumnata in subarctic birch forest: evidence of a recent outbreak range expansion. Journal of Animal Ecology, 77: 257–264. doi: 10.1111/j.1365-2656.2007.01339.x
- Issue published online: 7 DEC 2007
- Article first published online: 7 DEC 2007
- Received 25 June 2007; accepted 9 October 2007; Handling Editor: Mike Boots
- forest defoliation;
- global warming;
- insect attacks;
- population cycles
- 1Range expansions mediated by recent climate warming have been documented for many insect species, including some important forest pests. However, whether climate change also influences the eruptive dynamics of forest pest insects, and hence the ecological and economical consequences of outbreaks, is largely unresolved.
- 2Using historical outbreak records covering more than a century, we document recent outbreak range expansions of two species of cyclic geometrid moth, Operophtera brumata Bkh. (winter moth) and Epirrita autumnata L. (autumnal moth), in subarctic birch forest of northern Fennoscandia. The two species differ with respect to cold tolerance, and show strikingly different patterns in their recent outbreak range expansion.
- 3We show that, during the past 15–20 years, the less cold-tolerant species O. brumata has experienced a pronounced north-eastern expansion into areas previously dominated by E. autumnata outbreaks. Epirrita autumnata, on the other hand, has expanded the region in which it exhibits regular outbreaks into the coldest, most continental areas. Our findings support the suggestion that recent climate warming in the region is the most parsimonious explanation for the observed patterns.
- 4The presence of O. brumata outbreaks in regions previously affected solely by E. autumnata outbreaks is likely to increase the effective duration of local outbreaks, and hence have profound implications for the subarctic birch forest ecosystem.