Formed close to the K–Pg boundary, the Boltysh meteorite crater, Ukraine, preserves >400 m of lacustrine sedimentary rocks that include a record of the early Danian Dan-C2 hyperthermal event. Abundant pollen, spores and algae recovered from these sediments have yielded a cyclic record of plant ecology change paced by c. 21 kyr orbital precession cycles. New, higher resolution sampling across the inception of the Dan-C2 hyperthermal event has identified oscillations in vegetation community ecology at sub-orbital periods of c. 2 kyr, c. 200 years and c. 11 years. These are consistent with possible Hallstatt, DeVreis–Suess and Schwabe solar cycles, respectively. Rapid regime shift from savanna to a mesic forest ecosystem was paced by c. 21 kyr precession, with the shift probably occurring in <200 years. Prior to regime shift, c. 2 kyr (i.e. possible Hallstatt) oscillations between mesic- and winterwet-dominated plant communities increased in intensity, suggestive of ecological flickering.

Supplementary material: Detrended correspondence and changepoint analysis, palynological frequency data for DCA groups and core photographs are available at

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