Thermal homogenization of boreal communities in response to climate warming

authored by

Jussi Mäkinen, Emilie E. Ellis, Laura Henriques Antao, Andréa Davrinche, Anna-Liisa Laine, Marjo Saastamoinen, Irene Conenna, Maria H Hällfors, Andrea Santangeli, Elina Kaarlejärvi, Janne Heliölä, Ida-Maria Huikkonen, Mikko Kuussaari, Reima Leinonen, Aleksi Lehikoinen, Juha Pöyry, Anna Suuronen, Maija Salemaa, Tiina Tonteri, Kristiina Vuorio, Birger Skjelbred, Marko Jarvinen, Stina Drakare, Laurence Carvalho, Erik Welk, Gunnar Seidler, Pieter Vangansbeke, František Máliš, Radim Hédl, Alistair G. Auffret, Jan Plue, Pieter De Frenne, JM Kalwij, Jarno Vanhatalo, Tomas Valter Roslin

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.</jats:p>

External Organisation(s)

University of Helsinki
Finnish Environment Institute (SYKE)
Natural Resources Institute Finland (Luke)
Norwegian Institute for Water Research
Swedish University of Agricultural Sciences
Martin Luther University Halle-Wittenberg
Ghent University
Technical University in Zvolen
Karlsruhe Institute of Technology (KIT)

Type

Article

Journal

Proceedings of the National Academy of Sciences of the United States of America

Volume

122

ISSN

0027-8424

Publication date

29.04.2025

Publication status

Published

Peer reviewed

Yes

Sustainable Development Goals

SDG 13 - Climate Action, SDG 15 - Life on Land

Electronic version(s)

https://doi.org/10.1073/pnas.2415260122 (Access: Unknown)