Thermal homogenization of boreal communities in response to climate warming

Globally, rising temperatures are increasingly favoring warm-affiliated species. Although changes in community composition are typically measured by the mean temperature affinity of species (the community temperature index, CTI), they may be driven by different processes and accompanied by shifts in the diversity of temperature affinities and breadth of species thermal niches. To resolve the pathways to community warming in Finnish flora and fauna, we examined multidecadal changes in the dominance and diversity of temperature affinities among understory forest plant, freshwater phytoplankton, butterfly, moth, and bird communities. CTI increased for all animal communities, with no change observed for plants or phytoplankton. In addition, the diversity of temperature affinities declined for all groups except butterflies, and this loss was more pronounced for the fastest-warming communities. These changes were driven in animals mainly by a decrease in cold-affiliated species and an increase in warm-affiliated species. In plants and phytoplankton the decline of thermal diversity was driven by declines of both cold- and warm-affiliated species. Plant and moth communities were increasingly dominated by thermal specialist species, and birds by thermal generalists. In general, climate warming outpaced changes in both the mean and diversity of temperature affinities of communities. Our results highlight the complex dynamics underpinning the thermal reorganization of communities across a large spatiotemporal gradient, revealing that extinctions of cold-affiliated species and colonization by warm-affiliated species lag behind changes in ambient temperature, while communities become less thermally diverse. Such changes can have important implications for community structure and ecosystem functioning under accelerating rates of climate change.

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Publication Details

Journal
Proceedings of the National Academy of Sciences
Published
2025-04-21
DOI
https://doi.org/10.1073/pnas.2415260122
Citations
5
Primary Topic
Species Distribution and Climate Change
Type
article
Field-Weighted Citation Impact
9.19

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article

Thermal homogenization of boreal communities in response to climate warming

Juha Pöyry, Pieter De Frenne, Irene Conenna, Alistair G. Auffret et al.
5 citations
Proceedings of the National Academy of Sciences
Species Distribution and Climate Change
9.19
article

Thermal homogenization of boreal communities in response to climate warming

Juha Pöyry, Pieter De Frenne, Irene Conenna, Alistair G. Auffret, Andrea Santangeli, Laurence Carvalho, Jesse M. Kalwij, Tomas V. Roslin, Elina Kaarlejärvi, Janne Heliölä, Emilie E. Ellis, Marko Järvinen, Tiina Tonteri, Reima Leinonen, Frantíšek Máliš, Stina Drakare, Marjo Saastamoinen, Kristiina Vuorio, Aleksi S. Lehikoinen, Jan Plue, Jarno P. Vanhatalo, Birger Skjelbred, Anna Suuronen, Maria Helena Hällfors, Maija Salemaa, Laura H. Antão, Erik Welk, Jussi Mäkinen, Radim Hédl, Pieter Vangansbeke, Andréa Davrinche, Mikko Kuussaari, Anna‐Liisa Laine, Gunnar Seidler, Ida-Maria Huikkonen
article en
5 citations

Abstract

Globally, rising temperatures are increasingly favoring warm-affiliated species. Although changes in community composition are typically measured by the mean temperature affinity of species (the community temperature index, CTI), they may be driven by different processes and accompanied by shifts in the diversity of temperature affinities and breadth of species thermal niches. To resolve the pathways to community warming in Finnish flora and fauna, we examined multidecadal changes in the dominance and diversity of temperature affinities among understory forest plant, freshwater phytoplankton, butterfly, moth, and bird communities. CTI increased for all animal communities, with no change observed for plants or phytoplankton. In addition, the diversity of temperature affinities declined for all groups except butterflies, and this loss was more pronounced for the fastest-warming communities. These changes were driven in animals mainly by a decrease in cold-affiliated species and an increase in warm-affiliated species. In plants and phytoplankton the decline of thermal diversity was driven by declines of both cold- and warm-affiliated species. Plant and moth communities were increasingly dominated by thermal specialist species, and birds by thermal generalists. In general, climate warming outpaced changes in both the mean and diversity of temperature affinities of communities. Our results highlight the complex dynamics underpinning the thermal reorganization of communities across a large spatiotemporal gradient, revealing that extinctions of cold-affiliated species and colonization by warm-affiliated species lag behind changes in ambient temperature, while communities become less thermally diverse. Such changes can have important implications for community structure and ecosystem functioning under accelerating rates of climate change.

Proceedings of the National Academy of SciencesVol. 122(17)
Karlsruhe Institute of Technology (DE), University of Helsinki (FI), University of Turku (FI), National Academies of Sciences, Engineering, and Medicine (US), Czech Academy of Sciences (CZ), University of Johannesburg (ZA), Finnish Environment Institute (FI), Luther University (KR), Ghent University Hospital (BE), Norwegian Institute for Water Research (NO), Swedish University of Agricultural Sciences (SE), Natural Resources Institute Finland (FI), Technická univerzita vo Zvolene (SK), Finnish Museum of Natural History (FI), Centres for Economic Development, Transport and the Environment (FI), Institute of Geography of the Slovak Academy of Sciences (SK), Universitat de les Illes Balears (ES), Palacký University Olomouc (CZ)
Helsingin Yliopisto, European Commission, Svenska Forskningsrådet Formas, Academy of Finland, Jane ja Aatos Erkon Säätiö, Akademie Věd České Republiky, Vetenskapsrådet, Sveriges Lantbruksuniversitet, Universiteit Gent, Turun Yliopisto, University of Johannesburg, Univerzita Palackého v Olomouci, Universitat de les Illes Balears, Norsk Institutt for Vannforskning, Suomen Ympäristökeskus, Horizon 2020 Framework Programme, Consejo Superior de Investigaciones Científicas, Institute of Botany of the Czech Academy of Sciences, H2020 Marie Skłodowska-Curie Actions, HORIZON EUROPE European Research Council
Climate action
Openalex Percentile: Top 2%
Species Distribution and Climate Change
9.19
DOIOpen Access PDFOpenAlex
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