A mosaic of vegetation types and numerous lakes/wetlands, which vary from freshwater to saline, exist within the highly biodiverse region of South-west Western Australia (SWWA). In many parts of this region dryland and stream salinity is a major concern to farmers, land management and conservation agencies. Numerous studies have investigated the causes, mechanisms, nature and extent of contemporary dryland and stream salinity in the region, as well as remedies to alleviate it. However, there is currently no palaeo (pre-historical) record of salinization for the SWWA.
This research investigated early to late Holocene (i.e. pre-historical) salinity, vegetation and fire history of a study area (40km NW of Mt Barker, SWWA) to gain insight to the complex processes that have driven palaeoenvironmental variation in the region. Stratigraphic sequences of lake/wetland sedimentary cores from the study area indicate environmental variation in the landscape through time but shed no light on the nature or drivers of this observed variation. Multi-proxy indicators, in particular, fossil diatoms, geochemical markers, fossil pollen and fossil charcoal extracted from the lake/wetland sediments have been used to generate stand-alone palaeoenvironmental records. These records provide information about past variation of the lake/wetland salinity and geochemistry, the vegetation and the fire regimes enabling an inferred palaeoenvironmental reconstruction for the landscape of study area, using analogies to present day conditions and processes.
It is anticipated that these prehistorical records will provide a useful baseline for land management and conservation agencies that will furnish insights into the nature and degree of palaeo salinization of the lakes/wetlands and landscape of the study area. Such insights are useful when determining present day targets for the rehabilitation of areas affected by dryland and stream salinity in SWWA as salinization has been an intermittent feature of many of the lakes/wetlands and landscape of SWWA.