Climate warming dampens masting-driven pulsed resources

This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint. You must log in to post a comment. There are no comments or no comments have been made public for this article. This is a Preprint and has not been peer reviewed. This is version 1 of this Preprint. Add a Comment You must log in to post a comment. Comments There are no comments or no comments have been made public for this article. Pulsed resources arise when environmental forcing synchronizes biological responses. This synchrony generates episodic booms and busts that structure food webs. Mast seeding is a major example, yet climate warming is increasingly disrupting the synchrony that underpins these pulses. Importantly, the ecological consequences of masting depend on which tail is synchronized: spatially coherent seed failures (synchrony in the lower tail) create trophic bottlenecks, whereas coherent mast peaks (upper tail) generate resource pulses that fuel consumer outbreaks. Climate-driven changes in synchrony may be tail-specific, reshaping not only the strength but also the character of resource pulses. Here, we test how warming-driven changes in European beech (\textit{Fagus sylvatica}) masting translate into tail-specific shifts in spatial synchrony and whether these shifts arise from altered coupling between weather cues and reproduction. Using 45 years of individual-tree seed production data from the United Kingdom and 33 years of seed harvest records from Poland, we found that, as predicted, synchrony declined strongly in mast peaks (44\% locally; 50\% regionally). However, synchrony also declined in failure years, though to a lesser extent (35\% locally; 25\% regionally) than in mast peaks. This asymmetry was not explained by increasing heterogeneity in responses to the warm-summer cue preceding flowering. Instead, reproductive dynamics shifted toward dominance of the cold-summer cue two years before seedfall, while sensitivity to the warm-summer cue weakened. This flattened previously nonlinear cue–reproduction relationships: reproduction increasingly occurred under conditions that formerly produced synchronized failure, and amplification during favourable years was reduced. Our findings show that warming alters the cue structures that generate masting-driven pulses, weakening and desynchronizing both failures and peaks, and reducing their predictability. https://doi.org/10.32942/X2666T Ecology and Evolutionary Biology Published: 2026-02-17 06:56 Last Updated: 2026-02-17 06:56 CC BY Attribution 4.0 International Language: English