Prescribed fire alters foliar stoichiometry and nutrient resorption in the understorey of a subtropical eucalypt forest

Changes to soil nutrient concentrations following vegetation fire may affect biogeochemical cycling and foliar stoichiometry. Phosphorus (P)-limited plant communities are widespread and may be particularly sensitive to fire, but have received relatively little research attention in this context. We measured soil nutrient concentrations, foliar carbon (C), nitrogen (N) and P stoichiometry of understorey plants in a recently, frequently burned eucalyptus forest area in south-east Queensland, Australia, and compared these properties to an adjacent unburned area. Surface soils in the area subjected to relatively recent, frequent prescribed burning had higher P concentrations than those in the adjacent unburned area, although this did not include the 'available' forms of P. All plant species had high foliar N:P ratios, regardless of fire history, consistent with widespread P-limitation. Some species had lower foliar N:P ratios in the burned area, indicating interspecific variation in nutrient requirements and burning responses. The nutrient resorption proficiencies of a grasstree (Xanthorrhoea johnsonii Lee) were lower in the burned area, suggesting that the nutrient cycling of this species was made less conservative by burning. The stoichiometric patterns observed in the responses of plants to prescribed burning highlight the significance of fire in this P-impoverished plant community, and suggest the potential value of stoichiometric approaches in fire ecology.