Spatial heterogeneity in Holocene vegetation dynamics across Bass Strait and its regional paleoclimatic implications

Abstract We present a Late Pleistocene paleoecological record from King Island in western Bass Strait, Tasmania, and compare this to existing records from the eastern Bass Strait islands to improve our understanding of the region’s paleoecology and paleoclimatology. Vegetation change across the region followed similar trajectories during the late glacial–Middle Holocene, characterized by homogeneous warming and wetting trends. Spatial divergence occurred during the Middle Holocene when sea level rose, and different drivers began influencing western and eastern Bass Strait islands. In eastern Bass Strait, Middle Holocene sea-level rise caused replacement of woodland by coastal heathland, while in the west, a drier period accompanied by fires transformed forests to forest–scrub. The comparative analysis suggests that Westerly driven climatic anti-phasing was pronounced at higher latitudes of Tasmania during the late glacial–Early Holocene. A combination of weak Leeuwin Current, positive Indian Ocean Dipole (IOD), and El Niño–Southern Oscillation (ENSO) intensification contributed to Middle Holocene aridity across Bass Strait. Strong Westerlies and negative IOD phases led to greater regionalization of rainfall across western Bass Strait during the Late Holocene, while ENSO intensification drove rainfall declines in eastern Bass Strait. These findings provide new insights into the complexity of Late Pleistocene environmental dynamics across southeast Australia.