An integrated approach to mapping and understanding of vegetation: soil systems

•Gamma radiometric imagery adds a new dimension to traditional mapping exercises.•Mosaicity observed correlates to chemical working of soil by competing ecosystems.•The phytotarium emerges as base map unit of a hierarchy of soil/vegetation types•Use of multiple layers of evidence furthers insight on plant/soil relationships.

This research employs a raft of incisive strategies and technologies to define and interpret spatial relationships between native plant ecosystems and classes of soil across a range of scales. Building on traditional vegetation zonings and soil mappings, information on locations of key taxa, chemical composition of pisoliths and radiometric based technologies are used collectively to identify and delineate contrasting zonings in which principal base units (phytotaria) are distributed in patchy but well demarcated mosaics across soilscapes. At broadest scale biomes are recognised in terms of species endemism, radiometric patternings and element balances of pisolithic ferricretes and in many cases shown to change predictably in stepwise fashion across environmental gradients. At finer scale georeferenced data for key players in selected phytotaria are matched against information from airborne radiometry to identify hallmark signallings derived from workings of potassium, uranium and thorium in parent profiles. By draping radiometric signals over digital elevation models, further insight was obtained on the complex relationships between specific phytotaria, topography and mineralogical status across a selected area. These southwest Australian case studies demonstrate how multiple sources of evidence might be mined and parcelled up to provide a comprehensive picture of heterogeneity and connectivity within and between phytotaria.