Abandoned Orange-footed Scrubfowl (Megapodius reinwardt) nests and coastal rainforest boundary dynamics during the late Holocene in monsoonal Australia
The late Holocene history of monsoon rainforest retreat in northern Australia was explored by radiocarbon dating abandoned Orange-footed Scrubfowl (Megapodius reinwardt) nests. Scrubfowl can only build ‘nests’ (large heaps of soil and leaf litter) in coastal rainforests in northern Australia. A detailed study from a site with a known history of rainforest contraction demonstrated that it is impossible to accurately determine the date of rainforest boundary retreat by radiocarbon dating abandoned Scrubfowl nests. Nonetheless radiocarbon dates from abandoned nests at three sites on the coast of the Northern Territory suggested that the rainforests contracted sometime within the late Holocene. It is argued that the cause of such localised rainforest contraction is the combined effect of tropical cyclone damage and subsequent severe fires occurring in the storm debris, and not regional climatic change, a cause shown to be inconsistent with existing ecological and geomorphological data. The observed maintenance of rainforest boundaries under a regime of Aboriginal burning and the geographically patchy occurrence of abandoned Scrubfowl nests does not support the idea that Aborigines have been the primary cause of widespread rainforest retreat in the late Holocene.
