A late-Holocene pollen and charcoal record from King Island, Bass Strait, Australia

Abstract

A >2000 year-old sediment sequence from King Island, Bass Strait, Tasmania was analysed for pollen and charcoal to reconstruct late-Holocene landscape change, as well as identify past stands of Melaleuca ericifolia swamp forest which could have supported the King Island scrubtit. Coastal scrub, woodland and swamp forest dominated >2000 yrs BP, with oscillations between more open scrubland and closed forest occurring throughout the record corresponding with changes in lagoon water levels, sand dune movement, fire and European colonisation. The extreme dominance of the sand dune shrub Myoporum ~1600 yrs BP indicates sand dune impoundment of Bob Lagoon, which later led to permanent inundation of the site and an increase in aquatic herbaceous taxa. Melaleuca/Eucalyptus became dominant around the lagoon ~600 cal. yr BP, which suggests that swamp forest had become fully established for the first time in the sequence. This indicates that Bob Lagoon would have provided suitable habitat for the King Island scrubtit from this time until the lagoon was cleared for agriculture at the beginning of the twentieth century. Peaks in charcoal concentrations ~200 cal. BP show widespread landscape clearance by early European settlers, followed by the introduction of exotic taxa including Pinus. A comparison with other sediment records from King Island and elsewhere in Bass Strait reveals similar patterns of landscape openness, fire regimes and the impact of European colonisation in the region. The Bob Lagoon sequence fills both a chronological and eographical gap in palaeoecological records for King Island, as well as provides insight into past distributions of Melaleuca ericifolia swamp forest and by extension, the King Island scrubtit. Show more