Preservation biases in the fossil record distort species ecological niche and distribution models

Ecological niche models (ENMs) increasingly leverage the fossil record to
understand species’ environmental associations and predict their
geographic distributions. However, fossils do not occur uniformly through
time and space, which can compromise the robustness of ENMs and thus
affect ecological conclusions. Here, we assessed how preservation biases
in the fossil record impact our ability to reconstruct ecological niches
and distributions of North American small mammals during the late
Quaternary. First, using small mammal fossil occurrences and associated
depositional environment data, we quantified preservation potential (the
likelihood that a given environment supports fossil preservation) and the
preservation niche (environmental correlates of preservation) for three
late Quaternary time periods (the Last Glacial Maximum, the deglacial
period, and the Holocene). Second, we imposed the calculated preservation
potential on simulated distributions of six virtual species to evaluate
its impact on reconstructing species niches and geographic distributions
through time. We found that preservation potential was highest in the
Holocene and lowest during the deglacial, with the differences driven by
variations in climate and the prevalence of Holocene archaeological sites.
In all intervals, warm, wet, and highly seasonal environments exhibited
low preservation potential. These spatial and temporal differences in
preservation potential significantly influenced niche reconstructions and
geographic predictions, particularly impeding model quality when species
niches extended beyond the preservation niche. We warn that such
distortions can lead to erroneous ecological inferences, including
inaccurate predictions of species responses to environmental changes and
mischaracterizations of community assembly processes. We propose that our
approach to modelling preservation potential can be applied across
different regions, time periods, and taxonomic groups to help correct
distortions caused by sampling biases through weighted background point
selection that reflects these processes. Ultimately, this framework
enhances the ability to disentangle true ecological patterns from
preservation artifacts, improving the reliability of fossil-based
ecological and evolutionary inferences.