A collaboration of more than 87 researchers from 75 institutions
Climate change and species interactions are reshaping the distribution of the brown bear in Europe
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Understanding trophic relationships is key to explaining changes in species distributions and protecting ecosystems.
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The study analyzed over three million location points from around 3,000 bears across 14 European and Turkish subpopulations.
Tirana, June 4, 2025 – An international team, including researchers from the PPNEA, has studied how species interactions influence the distribution of brown bears across Europe and Turkey. The study found that, at a continental scale, brown bear distribution is largely shaped by interactions with other species—specifically, bears tend to occupy areas where species they feed on are also present. Published in Global Change Biology, this research highlights the importance of species interactions in ecosystem conservation, using the brown bear as a case study.
Understanding how global changes—such as climate change or land use transformation—affect species is critical for conserving biodiversity and maintaining the ecosystem services nature provides, such as clean water, soil fertility, and pollination. For example, climate change is causing species to shift their ranges toward higher elevations or closer to the poles, where climate conditions remain within their tolerance limits. Until now, most studies have focused only on the direct effects of environmental changes (e.g., temperature, rainfall, agricultural use) on species distributions. This study, however, focuses on indirect effects, analyzing how species interactions shape these patterns.
“The bears showed a very diverse diet—we detected 276 different species,” explains Pablo M. Lucas, a researcher at the University of Seville. “Bears living in warmer areas, such as the Cantabrian Mountains, Greece, or Turkey, have a more vegetarian diet, while in colder areas like Scandinavia and Finland, they tend to be more carnivorous. This means that the role of the bear in the ecosystem varies, ranging from herbivore to top predator.”
Thanks to this large international effort, the team had access to more than three million bear locations from around 3,000 individuals, covering 14 different subpopulations in varied environmental contexts. “This allowed us to study how local interactions play out on a continental scale. We observed that bears tend to be present in areas with higher energy availability from their dietary species. For instance, in the Cantabrian Mountains, the presence of oaks and beeches—key food sources for this subpopulation—makes bear presence more likely. In other, more carnivorous subpopulations, bear presence is more closely tied to the distribution of wild ungulates like wild boar or deer,” explains PPNEA’s researcher Aleksandër Trajçe.
This information is especially valuable for predicting where species may live in the future and what ecological roles they may fulfill, in the face of climate change and land use shifts. It also reinforces the idea that conserving species requires protecting the ecosystems they depend on. “Changes in the distribution of species that bears feed on could shift their position in the food web and affect their local viability,” adds Lucas.
Other species with different characteristics from the brown bear—such as those with more specialized diets, limited mobility, or narrow environmental requirements—may respond differently to climate change, land use change, and shifts in their ecological interactions. Improving our understanding of these dynamics is essential for designing more effective strategies for biodiversity conservation and sustaining the ecosystem services nature provides.
This research was led by the University of Seville, Sapienza University of Rome, and the Institute of Nature Conservation in Poland, and involved 87 researchers from 75 institutions in 26 countries, including Spain’s National Museum of Natural Sciences (MNCN-CSIC), the Doñana Biological Station (EBD-CSIC), the University Grenoble Alpes and the French National Centre for Scientific Research (CNRS).
P.M. Lucas et al.. (2025) Trophic interactions are key to understanding the effects of global change on the distribution and functional role of the brown bear. Global Change Biology DOI: 10.1111/gcb.70252
Read the full RESEARCH ARTICLE here: https://ppnea.org/wp-content/uploads/2025/06/Global-Change-Biology-2025-Lucas-Trophic-Interactions-Are-Key-to-Understanding-the-Effects-of-Global-Change-on-the.pdf
For media inquiries:
Dr. Aleksandër Trajçe,
Director, PPNEA
Lorena Pyze Xhafaj,
Communications and Public Relations Manager, PPNEA
E-Mail: [email protected],
