Reconstructing the long-term ecological history of Long Island, Furneaux Group (Bass Strait), Lutruwita/Tasmania

Abstract

The Bass Strait islands are the elevated remnants of a now-submerged continental land bridge that connected the mainland of Australia to Lutruwita/Tasmania during low sea level phases of the Quaternery period. The Furneaux Group is made up of around 100 islands, harbouring a rich diversity of plants derived from glacial refugia and stepping-stone dispersal as millennial-scale climate change altered the land and seascape configuration of the land bridge. Despite the region’s significance, long-term ecological and environmental dynamics of most of these islands remain poorly known. We present the first palaeoecological study of Long Island, a small granite island of the Furneaux group, currently covered by extensive grasslands in the west and patches of forest and woodland in the east and north of the island. We use decadal to centennial-scale resolution palaeoecological evidence for vegetation, animal and fire dynamics, alongside historical accounts of vegetation changes inferred from aerial photo analysis, to develop a comprehensive record of the island’s long-term ecology. Results show that grasslands have been an important feature of the island for at least the last 1000 years, and are reminiscent of Last Glacial Maximum grasslands of the now-submerged Bassian Plain. Both aerial photo analysis and the palaeoecological record show increases in forest cover on the island’s eastern corner over the past four decades. We discuss these ecological dynamics in the context of environmental and climatic shifts. This study emphasises the importance of palaeoecological studies, specifically their value in understanding modern ecosystems in their historic context. This data is critical in understanding the island’s current landscape and how this might change into the future.

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