Can we use springtails to improve our understanding of Antarctic Ice Sheet history? — A case study from Dronning Maud Land

The presence of unique biological archives (e.g., springtails, Arthropoda: Collembola) in Antarctic ice-free regions provides powerful evidence for testing assumptions about when and how the current ice sheet reached its present-day configuration. Springtails, where present, may suggest long-term (thousands to millions of years) ice-free conditions. Springtails might also provide crucial evidence of ice-free conditions in locations (often inland) where cosmogenic nuclide data are complicated by the influence of cold-based ice. We use published geological dating evidence from Dronning Maud Land (DML), East Antarctica, a region where numerous ice-free mountains (nunataks) currently protrude through the East Antarctic Ice Sheet, to test the utility of Antarctic springtails for understanding the evolution of ice-free terrain. We first categorise and plot all published cosmogenic nuclide data (ages, isotope concentrations) across DML using a series of distinct criteria to determine if they show 1) strong evidence for long-lived ice-free terrain, 2) moderate evidence for long-lived ice-free terrain, or 3) a complex burial-exposure history. Second, we compare the distribution of Antarctic springtails (requiring ice-free habitat to survive in situ) against this geological evidence, guided by their molecular data, where available. Our results imply that springtail populations coincide with areas adjacent to high (+2000 m a.s.l.) nunataks that have remained ice-free over timescales of thousands and in some cases millions of years, a finding that is supported by molecular information in the Sør Rondane Mountains, DML. Given the heterogeneous (and short-range endemic) presence of many springtails, they offer scope to improve knowledge of ice sheet changes more widely in Antarctica.