ecosystem functioning; community ecology; phosphorus; climate change; drought; fire; nitrogen; stoichiometry; competition
Mariotte Pierre, Creswell Tom, Johansen Mathew, Harisson Jennifer, Keitel Claudia, Dijkstra Feike A. (2020), Plant uptake of nitrogen and phosphorus among grassland species affected by drought along a soil phosphorus gradient, in Plant and Soil
, 48, 121-132.
Canarini Alberto, Mariotte Pierre, Ingram Lachlan, Merchant Andrew, Dijkstra Feike A. (2018), Mineral-Associated Soil Carbon is Resistant to Drought but Sensitive to Legumes and Microbial Biomass in an Australian Grassland, in Ecosystems
, 21(2), 349-359.
Mariotte Pierre, Canarini Alberto, Dijkstra Feike A. (2017), Stoichiometric N:P flexibility and mycorrhizal symbiosis favour plant resistance against drought, in Journal of Ecology
, 105(4), 958-967.
Canarini Alberto, Carillo Yolima, Mariotte Pierre, Ingram Lachlan, Dijkstra Feike (2016), Soil microbial community resistance to drought and links to C stabilization in an Australian grassland, in Soil Biology & Biochemistry
, (103), 171-180.
Canarini Alberto, Mariotte Pierre, Dijkstra Feike A., Mineral associated soil carbon is resistant to drought but sensitive to legumes and microbial biomass in an Australian grassland, in Ecosystems
Mariotte Pierre, Canarini Alberto, Dijkstra Feike A., Stoichiometric N:P flexibility and mycorrhizal symbiosis favor plant resistance against drought, in Journal of Ecology
The global climate is changing dramatically due to anthropogenic greenhouse gas emissions. In South-Australia, a trend of prolonged periods without rain, alternated with increasing rainfall intensity, has already emerged during the last 50 years and is likely to continue during this century. More extreme rainfall patterns affect plant growth, which can lead to an increase in fire frequency and intensity. Drought and fire impact on the relative supply of nitrogen (N) and phosphorus (P) to plants and microbes with contrasting effects depending on soils types. Because plants and microbes have limited flexibility to take up N and P under conditions of unbalanced supply, drought and fire affecting N:P stoichiometry can have large impacts on primary productivity, plant community structure and carbon sequestration. However, nothing is really known about the impacts of drought and fire on plant and microbes competition for nutrients in grasslands. By using field and glasshouse experiments, this project aim at assessing limitation of soil N and P for plant growth and microbes under climate change (drought and fire), depending on rainfall variability and soil properties in Australian grasslands. Isotopes tracers (15N, 32P) will be used to determine the uptake of nitrogen and phosphorus by plants and microbes under drought and fire. Moreover, several ecosystem functions will be measured, such as litter decomposition, soil respiration and plant productivity, in order to related changes in soil N:P stoichiometry, plant and microbes uptakes and grassland functioning and sustainability. Collected data will be then integrated into a model to determine how independent fluxes of N and P affect the relationships between soil available, plant and microbial N:P ratios under conditions of drought and fire. Because climate change can dramatically alter the relative availability of N and P, incorporating stoichiometric constraints into models is critical in predicting ecosystem responses to climate change, specifically to drought and fire that have perhaps some of the largest impacts on reshaping the Australian landscape. This project will identify important mechanisms and provide tools to improve predictions about drought and fire impacts on plant productivity but also on soil nutrient availability, that will have important implications for grassland management.