Reserving nitrogen in soils through microbial nitrate reduction to ammonium. This project aims to identify those microbes able to transform nitrate to ammonium and thus increase soil nitrogen conservation. More than 50 per cent of the nitrogen in fertilisers applied to soils is lost into the environment, which is both a financial loss to farmers and a main anthropogenic source of nitrogen pollution. Some microbes can transform nitrate into ammonium through dissimilatory reduction (DNRA) and thus ....Reserving nitrogen in soils through microbial nitrate reduction to ammonium. This project aims to identify those microbes able to transform nitrate to ammonium and thus increase soil nitrogen conservation. More than 50 per cent of the nitrogen in fertilisers applied to soils is lost into the environment, which is both a financial loss to farmers and a main anthropogenic source of nitrogen pollution. Some microbes can transform nitrate into ammonium through dissimilatory reduction (DNRA) and thus increase soil nitrogen retention. However, the DNRA process and the responsible microbial groups remain largely unknown. This project plans to use isotope tracing and biomolecular approaches to identify those DNRA microbial groups and elucidate the DNRA reaction process. The findings may support the use of DNRA to improve soil nitrogen.Read moreRead less
Get tough, get toxic or get a bodyguard: how root herbivores shape grass defences. The weight of root-feeding beetles can exceed that of sheep on Australian pastures and can result in significant losses in productivity. Grasses fight back against aboveground herbivores using toughness (physical defence), toxicity (chemical defence) and bodyguards (recruitment of the herbivore’s enemies). Little is known about belowground defences however, but grasses depend on roots for re-growth so good root de ....Get tough, get toxic or get a bodyguard: how root herbivores shape grass defences. The weight of root-feeding beetles can exceed that of sheep on Australian pastures and can result in significant losses in productivity. Grasses fight back against aboveground herbivores using toughness (physical defence), toxicity (chemical defence) and bodyguards (recruitment of the herbivore’s enemies). Little is known about belowground defences however, but grasses depend on roots for re-growth so good root defences seem essential. This study will apply optimal defence theory to consider these three defences against belowground herbivory across a range of grasses. The project will ask whether domestication has disarmed grass species and if defensive traits differ between photosynthetic pathways, before field-testing these patterns with root herbivore populations. Read moreRead less
The role of plant-soil feedback in biodiversity maintenance along fertility gradients: from patterns to mechanisms. Plants strongly modify soils and their associated biota, which in turn has important consequences for plant growth. This is known as 'plant-soil feedback'. This project will determine whether such feedback plays a role in maintaining the exceptionally high levels of plant biodiversity found in the kwongan shrublands of south-western Australia.