Applied Animal Physiology Group
Dr James Van Dyke
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We are broadly interested in how animals “work”. Animals must balance demands of competing physiological functions to maintain homeostasis and survive. They also need to be able to consume enough energy and biomolecules in order to grow and reproduce. We study how environmental changes impact on these processes to determine how individual animals are affected by environmental change.
Freshwater Turtle Conservation
Currently, one of our focal areas of research is to understand the causes of freshwater turtle declines in Australia, and to develop novel ways of stopping those declines.
Many freshwater turtle populations are composed primarily of older adult turtles, indicating that there is a lack of juvenile recruitment. So far, the evidence points to invasive red foxes (Vulpes vulpes) as being a major driver of turtle declines. Foxes destroy over 90% of most turtle nests, and this could mean that very few hatchlings reach the water. We are testing this hypothesis by developing a number of methods to protect turtle nests.
We work closely with local community groups to implement these approaches throughout south-eastern Australia, and citizen science is becoming a major forefront of our research. If these methods work, we should see a corresponding increase in the number of juvenile turtles in the system. Alternatively, if these methods do not work, then they indicate that some other factor is killing juvenile turtles between the time that they hatch, and the time that they would reach sexual maturity.
We are testing this hypothesis using medium-term mark-recapture and telemetry methods. At the same time, we are examining the effects of pollution and climate change on turtle reproduction and development. We are especially interested in how changes in the foodweb may be impacting the food available to turtles, with consequences for their growth, survival, and reproduction.
Evolution and function of vertebrate placentas
Another field of our research is the evolution and physiology of the placenta in live-bearing vertebrates. The placenta connects a mother to embryos that are not genetically identical to her (half of their genes are from their father), and there is a risk that her immune system might kill them. How placentas provide nutrition to embryos, despite this immune challenge, has major implications for understanding how reproduction, development, and immune function are regulated so that both mother and baby survive.
More broadly, all animals deal with similar immune and environmental challenges, and use many of the same molecular and physiological mechanisms to survive. Hence, animals are excellent models for discovering novel therapies for humans. The complex dynamic between placental and immune function may even explain why men and women suffer different rates of autoimmune diseases and cancer.
We use a range of molecular and physiological techniques to study these mechanisms to improve environmental outcomes, with potential to help human health as well.
Reproduction and environmental change
Animals must successfully deal with a number of environmental challenges in order to survive and reproduce the next generation. Our research aims to discover the novel mechanisms animals use to deal with environmental impacts on reproduction, development, and immune function.
We are particularly interested in Applied Animal Physiology Group nutritional and pollution impacts. The nutrients animals eat provide both the energy and chemical building blocks animals need to produce new molecules, cells, and tissues. Pollutants, including heavy metals, interact with molecular processes and cause breakdowns in reproduction, development, and immunity.
Two examples of our research focus on freshwater turtles, which have remarkable immune systems. Adults use a powerful innate immune response to prevent systemic bacterial infections after injuries. Eggs resist fungal infections despite not having an immune system aside from the immune factors provided by their mother during egg production.
We use molecular and physiological approaches to determine how these functions work, and how they are maintained despite food restrictions and pollution