Temporal uncertainty in fossil records can distort distributions and ecological niches during periods of climatic instability

Abstract

Reliable models of species niches and distributions depend on accurately matching occurrences to environments via spatial and temporal coordinates. For fossil occurrences, time-averaging and age uncertainty can create mismatches between fossils and their associated environments, distorting inferred niches and distributions. Using a virtual ecology approach, we assessed how temporal uncertainty ({+/-}200 years to the full late Quaternary) influences niche and distribution estimates for four virtual species centered on three periods: Holocene (6,000 y.b.p), deglacial (13,500 y.b.p.), and Last Glacial Maximum (18,000 k.y.b.p.). We compared uncertain estimates, derived by matching occurrences with environmental layers drawn from different times within each uncertainty window, against true niches and distributions. We found that during environmentally stable intervals, niches and distributions were robust to temporal uncertainty until it reached {+/-}2500 years. Higher environmental variability reduced accuracy, with the greatest mismatch occurring during the deglacial. These results demonstrate both the promise and limitations of paleodistribution reconstruction.