HIGH-RESOLUTION POLLEN RECORDS FROM NEW ENGLAND DURING THE 8.2 KA CLIMATIC REVERSAL

With anthropogenic climate change, investigating past plant communities' response to abrupt climatic reversals is increasingly important for characterizing how modern plant communities might respond to modern warming. Here, we investigate the response of vegetation to the 8.2 ka event, an abrupt climate oscillation in the North Atlantic region. High-resolution intervals of pollen data from radiocarbon-dated sediment cores from Rocky Pond, MA (ca. 8.8-7.2 ka; ~25 yrs/cm) and Davis Pond, MA (ca. 9.0-7.0ka; ~20 yrs/cm) show individualized changes in pollen taxa around the time of the 8.2 event. At ca. 8.0 ka, the pollen record from Rocky Pond shows a peak in pine (Pinus) pollen abundance and a corresponding low in oak (Quercus) pollen abundance, whereas the pollen record from Davis Pond shows high beech (Fagus) and low oak pollen abundances. A comparison of Rocky Pond with the pollen records from nearby Crooked Pond and Blood Pond show consistent changes in oak, pine, hemlock (Tsuga), beech and ragweed (Ambrosia) pollen abundances around 8.2 ka. A decline in the abundance of ragweed pollen at these three ponds is consistent with inferences for an interval of open landscape within the region prior to ca. 8.0 ka. Pollen influx data from Rocky Pond reveal a peak in pollen deposition rates (in both total pollen and some individual taxa) at ca. 8.2 ka, while the pollen influx from Davis Pond shows little to no change. Neither Rocky Pond nor Davis Pond records a singular, prominent change in pollen taxa specifically attributable to the 8.2 ka event. Multiple changes in individual pollen taxa within 100 years of the 8.2 ka event may indicate minimal community turnover associated with the event, while differences between ponds may result from the coastal location of Rocky Pond relative to the interior Davis Pond.