Alaskan archaeological sediment metabarcoding data
Sedimentary ancient DNA (sedaDNA) has huge potential to expand our knowledge of past human resource use and exploitation from open and near-surface archaeological sites. However, sediment from such sites is often not water-logged or frozen, and so the vertical movement of free water through the sediment, coupled with root penetration of overlaying vegetation, has the potential to blur and mix sedaDNA signals from different stratigraphic horizons. Here, we generated plant and animal metabarcoding data from archaeological sites in interior Alaska. We show evidence for a temporally mixed plant sedaDNA signal in the archaeological sediments. On the other hand, sporadic animal sedaDNA occurrences closely mirror expectations from site-specific zooarchaeological records. The results suggest that root penetration may be the dominant driver of cross-stratigraphic sedaDNA mixing in non-frozen sediments and that such taphonomic factors should be accounted for when assembling plant taxonomic inventories from these settings.