Mangroves as successional stages on the Hawkesbury River

Abstract

The mangrove environments of the Hawkesbury River estuary, New South Wales, are described in relation to the geomorphic units of the marine and fluvial segments of the river. A model of seral succession is presented which sees mangrove environments replaced with saltmarsh and Casuarina associations with continued progradation during the Holocene stillstand. Preserved mangrove peats beneath the Juncus kraussii plains of Mangrove Creek, a tributary of the Hawkesbury, are presented as evidence supporting this model. Recent expansion of mangroves into the saltmarsh is therefore contrary to the longer-term successional trend of the Holocene.