How individual behaviour shapes ecosystem functions

We investigate how individual differences and developmental changes in nutcracker behaviour influence both bird fitness and Swiss stone pine dispersal. Specifically, we aim to (1) assess behavioural variation in seed caching and its development over time, (2) quantify its effects on nutcracker survival, reproduction, and dispersal and (3) model how these behaviours shape Swiss stone pine recruitment and upslope range shifts under climate change.

We capture juvenile and adult nutcrackers in the Swiss Alps and equip them with solar-powered GPS tags to record their year-round movements. GPS and accelerometer data help identify seed caching, survival and breeding behavior. Using movement analysis and ecological models, we link behavioral types and their development to survival, reproduction, and dispersal of nutcrackers. Finally, we integrate these data with pine seedling establishment models to predict their effects on forest dynamics under climate change.

This project addresses a critical gap in understanding how individual behavioural variation and its ontogenetic development shape ecosystem functions. By studying the nutcracker–Swiss stone pine mutualism, we aim to uncover how, and under which conditions, specific behaviours benefit or impede fitness components of both partners. These insights will advance our ecological understanding, improve predictions of ecosystem responses to global change, and inform conservation of emblematic Alpine habitats.

Our findings reveal age- and individual-based differences in nutcracker behaviour associated with seed dispersal. Adults followed two distinct seed dispersal strategies: short-distance caching at high elevations vs. long-distance caching at lower elevation sites. Juveniles dispersed seeds over larger ranges and cached at higher elevations than adults and were less efficient and less skilled in cone handling. These individual and ontogenetic differences thus affect the quantity, quality and spatial pattern of dispersed seeds with potential downstream effects on pine recruitment.

• PD Dr. Eike Lena Neuschulz, Senckenberg Biodiversity and Climate Research Centre, Frankfurt
• Prof. Dr. Thomas Müller, Senckenberg Biodiversity and Climate Research Centre, Frankfurt
• Dr. Kurt Bollmann, Swiss Federal Institute for Forest, Snow and Landscape research WSL, Birmensdorf
• PD Dr. Michael Schaub, Swiss Ornithological Institute, Sempach
• Dr. Valentin Graf, Senckenberg Biodiversity and Climate Research Centre, Frankfurt

• Yvonne Jacob Foundation