The biogeochemistry of copper metallophytes in the Roseby Corridor (North-West Queensland, Australia)

The ability of Australian native metallophytes to tolerate extreme metal concentrations in the soil and other difficult edaphic conditions is still not well understood. Copper is an essential micronutrient for plants to survive, but at high concentrations (> 20 µg g−1) in plant tissues, it can cause foliar chlorosis, stunted growth, and ultimately plant death. The Roseby Corridor in Central Queensland (near Cloncurry) is host to copper metallophytes (Polycarpaea spirostylis, Bulbostylis barbata, Tephrosia virens, Eriachne mucronata) which are able to tolerate soils with total copper concentrations up to 12,700 µg g−1. Even with these high levels of copper in the rhizosphere, the maximum copper in all species is relatively low when compared to Cu concentrations in the soil (leaf/stem: Bulbostylis barbata: 40.9 µg g−1, Eriachne mucronata: 12.3 µg g−1, Polycarpaea spirostylis: 10.9 µg g−1, Tephrosia virens: 128 µg g−1). Therefore, all of these species can be classified as copper Excluder-type metallophytes. Their affinity to copper makes these metallophytes useful indicators of copper surface mineralisation within the Roseby Corridor