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Bjørn Økland

Research Professor

NIBIO Publications

Division of Biotechnology and Plant Health

Invertebrate Pests and Weeds in Forestry, Agriculture and Horticulture

(+47) 916 28 225
bjorn.okland@nibio.no

Place
Ås H8

Visiting address
Høgskoleveien 8, 1433 Ås

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Biography

My main research interests are:
  • Population dynamics of bark beetles
  • Determinants of insect diversity in forests
  • Climate change and insects
  • Invasive species

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Authors

Tomáš Hlásny Roman Modlinger Jostein Gohli Rupert Seidl Paal Krokene Iris Bernardinelli Simon Blaser Gediminas Brazaitis Gailenė Brazaitytė Eckehard G. Brockerhoff György Csóka Laura Dobor Maarten de Groot Mihai‐Leonard Duduman Massimo Faccoli Margarita Georgieva Georgi Georgiev Wojciech Grodzki Henrik Hartmann Anikó Hirka Gernot Hoch Tomasz Jabłoński Hervé Jactel Mats Jonsell Marija Kolšek Markus Melin Slobodan Milanović Constantin Nețoiu Mats Nieberg Bjørn Økland Milan Pernek Michaela Perunová Nick Schafstall Martin Schroeder Gottfried Steyrer Jozef Vakula Thomas Wohlgemuth Tiina Ylioja Andrew M. Liebhold

Abstract

ABSTRACT Ongoing shifts in climate and land use have altered interactions between trees and insect herbivores, changing biotic disturbance regimes. However, as these changes are complex and vary across host species, insect taxa, and feeding guilds, they remain poorly understood. We compiled annual records of forest insect disturbance from 15 countries in temperate and boreal Europe, spanning the period from 2000 to 2022. The dataset comprises 1361 time series characterizing the dynamics of 50 herbivorous insects. We used this dataset to test whether insect disturbance has systematically changed during the 23‐year period across host trees and feeding guilds, whether it varies along latitudinal and climatic gradients, and whether synchrony exists among species in the same guild or among species sharing the same host. Since 2000, borer disturbance was predominantly concentrated on gymnosperms, while defoliators impacted gymnosperms and angiosperms more evenly. While 85.8% of gymnosperm disturbance was inflicted by a single species, Ips typographus , the majority of disturbances to angiosperms were caused by six different species. Borer impact on gymnosperms has increased in the 21st century, while defoliator impact has decreased across both clades. In contrast to diverging temporal trends, disturbance was consistently greater in warmer and drier conditions across feeding guilds and host types. We identified significant synchrony in insect disturbance within host types and feeding guilds but not between these groups, suggesting shared drivers within guilds and host types. Increasing insect disturbance to gymnosperms may catalyze adaptive transformations in Europe's forests, promoting a shift from historical conifer‐dominated management to broadleaved trees, which are less affected by insect herbivores. Our findings reveal a diversity of trends in insect herbivory, underscoring the need to strengthen monitoring and research in order to better understand underlying mechanisms and identify emerging threats that may not be apparent in currently available data.

Authors

Bjørn Økland

Abstract

No abstract has been registered

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Authors

Tomáš Hlásny Michaela Perunová Roman Modlinger Max Blake Gediminas Brazaitis György Csóka Maarten de Groot Mihai-Leonard Duduman Massimo Faccoli Margarita Georgieva Georgi Georgiev Wojciech Grodzki Henrik Hartmann Anikó Hirka Gernot Hoch Hervé Jactel Mats Jonsell Marija Kolšek Paal Krokene Markus Melin Slobodan Milanović Bjørn Økland Milan Pernek Gilles San Martin Martin Schroeder Rupert Seidl Jozef Vakula Tiina Ylioja

Abstract

No abstract has been registered

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