title: Specialists in ancient trees are more affected by climate than generalists.
abstract: Ancient trees are considered one of the most important habitats for biodiversity in Europe and North America. They support exceptional numbers of specialized species, including a range of rare and endangered wood-living insects. In this study, we use a dataset of 105 sites spanning a climatic gradient along the oak range of Norway and Sweden to investigate the importance of temperature and precipitation on beetle species richness in ancient, hollow oak trees. We expected that increased summer temperature would positively influence all wood-living beetle species whereas precipitation would be less important with a negligible or negative impact. Surprisingly, only oak-specialist beetles with a northern distribution increased in species richness with temperature. Few specialist beetles and no generalist beetles responded to the rise of 4°C in summer as covered by our climatic gradient. The negative effect of precipitation affected more specialist species than did temperature, whereas the generalists remained unaffected. In summary, we suggest that increased summer temperature is likely to benefit a few specialist beetles within this dead wood community, but a larger number of specialists are likely to decline due to increased precipitation. In addition, generalist species will remain unaffected. To minimize adverse impacts of climate change on this important community, long-term management plans for ancient trees are important.
authors.affiliation: Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 AasNO-1432 Norway; Department of Life Sciences Imperial College London Silwood Park Campus Ascot Berkshire SL5 7PY United Kingdom.
authors.forename: Leonie A
authors.identifier: 0000-0003-4952-6508
authors.initials: LA
authors.lastname: Gough
authors.affiliation: Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Aas NO-1432 Norway.
authors.forename: Anne
authors.initials: A
authors.lastname: Sverdrup-Thygeson
authors.affiliation: IFM Biology Conservation Ecology Group Linköping University Linköping SE-581 83 Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Milberg
authors.affiliation: Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Aas NO-1432 Norway.
authors.forename: Hanne E
authors.initials: HE
authors.lastname: Pilskog
authors.affiliation: IFM Biology Conservation Ecology Group Linköping University Linköping SE-581 83 Sweden.
authors.forename: Nicklas
authors.initials: N
authors.lastname: Jansson
authors.affiliation: Department of Ecology Swedish University of Agricultural Sciences Box 7044 Uppsala SE-750 07 Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Jonsell
authors.affiliation: Department of Ecology and Natural Resource Management Norwegian University of Life Sciences P.O. Box 5003 Aas NO-1432 Norway.
authors.forename: Tone
authors.initials: T
authors.lastname: Birkemoe
keywords: Beetles; climate gradient; coleoptera; precipitation; saproxylic; temperature