An ecological study of the central Queensland ultramafic endemic shrub Neoroepera buxifolia (Picrodendraceae), Australia

Abstract

The ultramafic endemic shrub Neoroepera buxifolia Muell.Arg. & F.Muell (Picrodendraceae) has high habitat specificity and is mostly restricted to the perennial and ephemeral creeks and drainage lines of the central Queensland ultramafic landscape. It has an association with high magnesium (Mg) concentrations in the soil and the present study seeks to determine whether there is a correlation between populations of N. buxifolia and the soil extractable Mg and/or Mg : calcium (Ca) quotients in the soil. This was achieved by measuring the standing volume, height and seedling counts of N. buxifolia against the soil elements and other plot characteristics. Whereas correlations were found between increased height of N. buxifolia and the Mg : Ca quotients, soil extractable nickel (Ni) had the greatest influence. The standing volume of N. buxifolia also increased with soil extractable Ni. The standing volume of N. buxifolia was greatest in the upper tributaries of the first-order ephemeral creeks and presence of permanent water of the perennial creeks did not influence the standing volume or height of N. buxfolia.

Global research on ultramafic (serpentine) ecosystems (8th International Conference on Serpentine Ecology in Sabah, Malaysia): a summary and synthesis

“…In addition, low macronutrient concentrations, high concentrations of some heavy metals, and low water availability are also important factors that must be tolerated by ultramafic plants. Several poster and oral presentations at the conference addressed ultramafic tolerance with respect to heavy metals and other nutrient imbalances in plants (Doronila et al 2014;Echevarria et al 2014;Pollard and Smith 2014;Teptina and Paukov 2014;Ghaderian et al 2015;Hendry et al 2015) and lichens (Paukov et al 2014;Favero-Longo et al 2015). Although studies generally focus on the effects of a single stress factor, these stress factors are likely to have combined effects (Von Wettberg et al 2014), as in the case for Ca : Mg ratio and water availability on traits of Mimulus guttatus (Phrymaceae, Murren et al 2006;Selby et al 2014).…”