Forest Biology Center

Our new study, published in Oikos, shows how flexible pollinator communities sustain reproduction in the mast-seeding tree Sorbus aucuparia. Despite large year-to-year swings in flowering intensity, pollination efficiency remained high, driven by dynamic shifts in pollinator composition. Bumblebees dominated during abundant flowering, while solitary bees became proportionally more important when flowers were scarce. These results reveal that pollinator life histories and network flexibility buffer animal-pollinated trees from pollination failure, helping explain why strong masting can evolve even in insect-pollinated species.
👉 Read the paper in Oikos.

The press release associated with the paper!

Global study reveals how weather drives plant reproduction—and how climate change may disrupt it.

A major new study published in Nature Communications has uncovered the global patterns linking weather and reproduction in perennial plants. The research, led by Valentin Journé and Michał Bogdziewicz from Adam Mickiewicz University in Poznań, analyzed long-term seed production records from 746 populations of 331 species across all vegetated continents.
The team found that temperature is the dominant cue for triggering reproduction, although its influence weakens in the wettest and driest climates.

Plants often reproduce in pulses—years of mass seed production followed by years of scarcity—a phenomenon known as masting. By examining decades of data, the researchers showed that in temperate and boreal zones, plants usually produce more seeds after warm years, while in tropical forests, reproduction peaks after unusually cool periods. This striking contrast means that global warming could amplify reproductive failures in the tropics, while making reproduction more regular—but less synchronized—in temperate forests.
“Our analysis shows that the same climatic force can have opposite effects in different parts of the world,” says Valentin Journé, lead author. “Tropical forests, which rely on rare cool spells to trigger flowering, may face widespread declines in reproduction as these events become even rarer.”

The study also found that plant species that show the most extreme seed production cycles—such as oaks, beeches, or some conifers—are the most sensitive to temperature fluctuations. “These hypersensitive species synchronize reproduction over vast areas,” explains Michał Bogdziewicz. “That makes them particularly vulnerable: even small shifts in temperature patterns can disrupt this synchrony and weaken the benefits of masting, like pollination success and predator satiation.”

The researchers warn that such disruptions could cascade through ecosystems. Many animals—from rodents to birds and large herbivores—depend on masting events for food, and reduced seed years may slow forest regeneration. “Masting shapes how forests feed and renew themselves,” adds Jessie Foest, co-author of the study. “Understanding its climatic drivers helps us foresee where ecosystems are most at risk under ongoing warming.”
By providing the first global test of long-standing ecological theories, the study offers a framework for predicting how plant reproduction will respond to changing climates. As Bogdziewicz summarizes, “We are finally able to see the big picture—how weather links the lives of plants around the world, and how those links are now being tested by climate change.”

Journé V., Kelly D., Hacket-Pain A., Pearse I., Szymkowiak J., Foest J., Kondrat K., Oberklammer I. Pesendorfer M., Satake A., Bogdziewicz M. (2025) Weather drivers of reproductive variability in perennial plants and their implications for climate change risks. Nature Communications, https://doi.org/10.1038/s41467-025-64300-6

Over new study, based on 39-year of ecological monitoring in Maine, USA,  analyzed white-footed mice (Peromyscus leucopus) abundance and associated forest and climatic data. We found that mouse abundance increased by ~67 % and average weight by ~15 % during the study period. These trends were driven primarily by rising acorn production — a result of both forest maturation (larger oak trees producing more seeds) and warmer spring temperatures. Mice that were heavier also showed higher survival probabilities. Our findings underline how long-term shifts in resource availability—mediated by forest growth and climate change—can cascade through ecosystems by altering consumer population dynamics and traits. Read the full paper here: https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2656.70114

Maria will join our team in October, working on the climate change biology of trees reproduction, which will include altitudinal gradients in fecundity, local adaptations, and more. Stay tuned for outcomes!

Our new review explores the phenomenon of mast seeding, where perennial plants produce highly variable and synchronized seed crops. We synthesize current knowledge on the mechanisms plants use to achieve this variability, from hypersensitivity to weather cues to interactions between pollination, fruit maturation, and internal resource dynamics. We highlight that variation in flowering effort, rather than fruit maturation, is often the main driver of masting, and that weather cues synchronize reproduction more strongly than pollen limitation. The review also considers emerging genetic insights, challenges long-held assumptions about the geographic scope of masting, and examines how climate change and management contexts may reshape these patterns.

In the latest publication, co-authored by our colleague Urszula Eichert, you can read about the behaviour of captive-born European hamsters after being released into the wild. The study examined how sex, age, and the origin of the parent (from the wild or from captivity) affect the behaviour of the offspring in the first days after being placed in acclimatisation aviaries. The full paper can be accessed here:
https://doi.org/10.1016/j.gecco.2025.e03784

Our latest paper, Solstice, selection, and synchrony of seed masting, addresses how the summer solstice serves as a fixed, range-wide cue that synchronizes temperature sensing for flowering in European beech. Unlike growth processes, where local adaptation to environmental conditions is beneficial, masting relies on synchrony among individuals to enhance pollination efficiency and predator satiation. We show that this fixed-date cue, unaffected by local conditions, is key to achieving large-scale reproductive synchrony—but may also make masting vulnerable to climate warming. Read the whole story here: https://doi.org/10.1073/pnas.2515264122

We’re thrilled to announce that Dr. Jessie Foest has been awarded a Marie Skłodowska-Curie Actions ERA Fellowship for her project FECUND, which tackles the urgent issue of forest regeneration under changing climate conditions. The project will explore how climate conditions influence early life stages of trees, from seed production to recruitment, combining field data, experimental work, and ecological modelling. Supported by a Europe-wide research network and interdisciplinary collaboration, FECUND aims to generate vital insights into the factors driving forest resilience. Congratulations, Jessie!

I’m honoured to have received a START stipend from the Foundation for Polish Science (FNP). The award is designed to support early-career researchers, offering recognition for work to date and space to grow.

For me, it’s a deeply appreciated vote of confidence as I continue to build my research on forest regeneration and long-term seed production dynamics.

Many thanks to the FNP for supporting me and other early-career scientists across disciplines!

New research led by Dr Jessie Foest has just been published in Ecology, entitled:
“Intraspecific variation in masting across climate gradients is inconsistent with the environmental stress hypothesis.”

This study offers fresh insights into the diversity of reproductive strategies in trees and challenges long-standing assumptions in the field of mast seeding.

Masting – the phenomenon where trees produce large seed crops in some years and little to none in others – is often considered a species-level characteristic. But is that the full story? How much does masting vary between populations within a species?

This question has largely gone unanswered until now.
We analysed 437 long-term time series across 19 tree species and found that intraspecific variation in masting can exceed variation between species.

We also tested a widely held assumption, namely that climatic stress drives this variation. The environmental stress (or productivity gradient) hypothesis suggests that trees in more stressful, marginal climates exhibit more pronounced masting. However, our findings tell a different story:

• Populations growing toward climatic margins did not show greater variability in seed production.
• In fact, they exhibited more stable reproductive patterns – directly contradicting the environmental stress hypothesis.

This suggests that factors other than climatic stress / productivity may play a greater role in shaping masting, and calls for a re-evaluation of some foundational ideas in the field.

Improving our understanding of these mechanisms is crucial for predicting how forest ecosystems will respond to changing environmental conditions and for informing effective conservation and management strategies.

Read the full paper here.