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Senior Lecturer, Hawkesbury Institute for the Environment, Western Sydney University

Dr Kristine Crous is a Senior Lecturer, coming to Western Sydney University from the Australian National University.

Her research has focussed on physiological mechanisms plants use to respond to global climate change factors, principally elevated CO2 and climate warming, but also the effect of nutrient availability (both nitrogen and phosphorus) on the CO2 response.

In her previous postdoc at WSU, she investigated how nutrient availability affects the responses of photosynthesis and leaf respiration to elevated CO2 at EucFACE. In a unique project linking phosphorus (P) limitations to photosynthesis and growth, she combined extensive field work at EucFACE measuring gas exchange with low O2, a technique often used in labs but rarely in the field. These measurements were combined with challenging labwork critical to elucidate the observed field mechanisms during which she extracted leaf P and other P-containing components from the leaf. This work resulted in new insights in the role of photorespiration, regarded as a wasteful process, in leaf P-recycling.

She also has been pursuing the temperature responses of photosynthesis and respiration on large trees at the Hawkesbury Forest Experiment. Because of unprecedented rates of warming expected in this century, she has investigated the capacity of Eucalyptus species to adjust to warmer conditions, mostly on large trees. She demonstrated that warming reduced leaf respiration at a given temperature in summer, with drought further exacerbating this reduction (Crous et al. 2011). In a warming study on Eucalyptus globulus (Crous et al. 2013) she reported a physiological temperature limit in summer because air temperatures far exceeded the temperature optimum of the species. Building on this work, she and her collaborators found less capacity to cope with warming within two widely-distributed Eucalyptus species ranging from tropical to temperate climates (Drake et al. 2015). Her data have been incorporated in several large-scale models to understand future ecosystem functioning.

Recently, she won a 2016 ARC Discovery Early Career Award (DECRA) to investigate how rainforest species will cope with climate warming. The response of rainforest species to climate warming is one of the largest uncertainties in the future terrestrial carbon cycle. This work aims to give us a predictive capacity for the temperature sensitivity of unique rainforest species. A narrow temperature optimum of photosynthesis is expected in rainforests as these species are thought to be more specialised due to a thermally stable environment. This may mean reduced rates with warming if they have limited capacity to adjust. The multi-faceted nature of her DECRA proposal, combining observational and experimental approaches, will maximise our understanding of how, and how much, rainforest tree species will adjust to warmer temperatures while also relating these responses to climate variability.