Our postgraduate students
Insect herbivory of an invasive woody weed: identifying biological control agents
Coastal Tea-tree (Leptospermum laevigatum) is a native Australian species that has been widely used for dune stabilization in both Australia and South Africa. It has become an invasive weed in South Africa, South Australia and Western Australia. It rapidly spreads across coastal areas due to wind dispersed seeds and has become a major weed by forming dense stands which outcompete other native plant species and increases fire risk because of being highly flammable. Previous attempts to control Coastal Tea-tree have been confounded by the cost of chemical control, and regrowth following mechanical removal. Biological control could be effective, but has not been extensively employed because of the lack of information on biogeography and population biology of L. laevigatum and its associated insect herbivores that could be used as the biological control agents.
Our lab is collaborating with colleagues in South Africa to acquire essential ecological, genetic & chemical information about the plant in its endemic and introduced ranges with the ultimate view of assessing the potential for biological control using native Australian insect herbivores.
Behavioural partitioning of mainland and island lava lizard assemblages in Ecuador
Habitat physical structure has an extreme influence on the selective pressures in animal populations and can lead to several changes. The lava lizards (Microlophus sp.) are excellent model organisms for behavioural, ecological, and evolutionary studies, because of their distribution across mainland South America and the Galapagos Islands. In Ecuador, 11 species occupy the western dry forest near the mainland coast and the Galapagos Islands. This offers them different ecological characteristics within which species might exhibit different morphology and behaviour.
My PhD will combine the study of the habitat, behaviour, morphology, and community structure of the Ecuadorian lava lizards to understand the differences between island and mainland communities. Behavioural ecology is a growing field in my country, so many challenges lie ahead. However, they are of great importance for the conservation of the fauna, as well as to preserve well into the future the very diversity for which my country is so well known.
How C4 grasses shaped the ecology of eastern Australia
In the Northern Hemisphere, the evolution and rise of C4 grasses led to the creation of savannas and grasslands over 10 million years ago. These grasses sustained large grazing animals — ancient horses, buffalo, deer and others — and brought fire more frequently into landscapes. A mere 3 million years ago, savanna grasses arrived in Australia from Southeast Asia and the experience here was fundamentally different because of our long isolation and the lack of grazing herds.
My research is investigating how these sun-loving grasses could invade a land of trees and shrubs, and what happened when C4 grasses dispersed into ecosystems dominated by flora of Gondwanan origin.
The functional significance of ant colouration
Ants are of immense ecological importance and can be strikingly colourful, ranging from diaphanous yellows to intense reds. I am exploring the colour diversification of ants from a functional perspective in order to identify associations between colour traits and the environment. This will be achieved through a broad variety of approaches including field comparisons, behavioural trials, manipulative experiments, ultrastructural investigations, and visual modelling. This novel approach will potentially enable the development and application of colour-related traits in trait-based ecological studies, as well as contributing to our understanding of animal colouration more generally.
Farm-scale Natural Capital Accounting - Plant Biodiversity
With over half of Australia's land used for farming practices, farmers can make an important contribution to the conservation of our natural environment on private land. But all too often, agricultural production has come at the expense of the environment due to market pressures for high yields and quick profits. However, what the market often fails to appreciate, is that a sustainable and productive agricultural system requires a healthy, resilient and biodiverse environment. Natural capital (which includes all natural resources such as soils, water, plants and animals) can benefit farming systems by providing, for example, shelter for crops and livestock, nutrient cycling and water filtration, and habitat for wildlife that contribute to pollination and pest control.
My role in this project is to measure plant biodiversity on fifty farms across south-eastern Australia to determine how plant biodiversity varies with changes in natural capital. These measures will then be integrated into Natural Capital Accounts which will put a value on nature on farms and, in turn, encourage farm management that optimises both natural capital and production, and promote markets for sustainable agriculture.
Legacy effects of historical gold mining on floodplains of Victorian rivers
Many river catchments in Victoria were intensively mined during the period 1850 – 1890 leading to wide-scale deposition of mine tailings and changes in river and floodplain geomorphology. My project is directed towards understanding the geochemical changes that have occurred in these tailings deposits on river floodplains, with a particular focus on the upper and lower reaches of the Loddon River.
Elemental composition (using both in-field X-ray Fluorescence and laboratory techniques) and throughout stratigraphy (grain size distribution) of river bank deposits will be employed to differentiate the original (i.e. pre-mining) floodplain surface from more recently deposited tailings. Further investigation of the geochemical changes which have occurred to the mobilised parent minerals through river transport and exposure to the atmosphere will be achieved though semi-quantitative and quantitative XRD of river bank materials and microprobe (EPMA) analysis of arsenic (As)-containing particles. X-ray absorption spectroscopy will also be used to investigate changes to As speciation between source materials and river bank deposits. My work will assist in the future management of these mine tailings, and in understanding the possible toxicological risks to aquatic ecosystems.
Rewilding invertebrates and microbes for biodiversity and ecosystem function
Restoration ecology has historically focused on reconstructing highly visible groups (e.g., plants, vertebrates) whilst ignoring less visible ones, such as invertebrates and microbes. This is problematic as invertebrates and microbes make up the vast bulk of biodiversity and drive many key ecosystem functions. Yet, they are rarely actively reintroduced when they struggle to recolonise restoration sites, limiting ecosystem function and biodiversity in these areas.
My project responds to this shortfall by investigating how we can rewild dispersal-constrained invertebrates and microbes during ecological restoration. My research looks at the efficacy of inoculating restoration sites with litter transplants from biologically rich remnant sites, and its effect on biodiversity and the efficiency of leaf litter breakdown.
The dark side of night-lights: does energy-efficient lighting cause unexpected ecological damage?
It seems ironic that in a bid to combat climate change, and ultimately ‘save the planet’, we are making drastic changes to technology without a full understanding of the hidden ecological damage they might be causing. The introduction of energy-saving lighting, such as energy-efficient LEDs, may be having a great impact on the health of Australian wildlife. Exposure to artificial light can result in a wide range of biological effects on animals including, modified behaviour, disrupted foraging and altered timing of reproduction.
My research aims to identify both the ecological and health impacts of artificial night lighting on targeted groups of Australian mammals. I will then experimentally assess our ability to mitigate these impacts by changing the spectral composition of lights to produce “wildlife-friendly” lighting. Findings from my work will be directly used to generate Australian guidelines regarding lighting design and spectral wavelengths for wildlife-friendly night lighting in sensitive areas.
Sex and the city: Investigating the reproductive ecology of a successful urban species, the Gould’s Wattled Bat (Chalinolobus gouldii) in greater Melbourne.
Urban expansion is occurring rapidly worldwide, but our understanding of the effects of urbanisation on wildlife is poor. The success of some species in urban habitats provides valuable insight into evolutionary and selective processes that make them successful. Understanding the life-history strategies around reproduction is key to recognising the drivers associated with a species’ success in changing environments. The Gould’s Wattled Bat (Chalinolobus gouldii) has adapted to become one of the most common microbat species in greater Melbourne, Victoria.
Long-term monitoring of bat-boxes at multiple sites in greater Melbourne has shown that large numbers of Gould’s Wattled Bats occupy boxes year round, providing a unique opportunity to recapture both male and female bats at crucial times throughout the year to document drivers of reproductive success. With reproduction being a period of high energy demand, Gould’s Wattled Bats must overcome the pressures involved in finding adequate resources for themselves and their offspring to ensure the best chance of survival. I aim to build on knowledge gained through the monitoring program by investigating the mating system and reproductive biology of Gould’s Wattled Bats that occupy bat-boxes at multiple sites in greater Melbourne.
Multiple evidence of Aboriginal burning in lowland, mesic grassy ecosystems of south-eastern Australia
Just how Aborigines shaped Australia with fire has been fiercely contested by historians and ecologists. There is a need to review and test our understanding of the role of Aboriginal burning in particular environments such as these grasslands. It is argued that the non-alignment of historic grass/tree boundaries with soil patterns, in climatic regions where trees are expected, is evidence of an historic influence of ‘top-down’ processes like fire. And that the clustering of grasslands close to where Aborigines preferred to live, combined with archival accounts of the targeted, purposeful and frequent use of fire by Aborigines, suggests ‘fire–stick farming’ for the production of staple roots was likely instrumental in grassland formation and maintenance. Furthermore, confidence around the role of Aboriginal burning in influencing such vegetation patterns will only result from the acceptance of multiple inferential tests covering a range of multidisciplinary evidence lines, namely: (1) archival benchmarking and palaeoecology; (2) phytoecology, and; (3) ethnology and archaeology.
Managed Aquifer Recharge - Risks of injection clogging using recycled water in a confined alluvial aquifer
My research focuses on Managed Aquifer Recharge (MAR), which involves a range of methods to recharge water underground such as infiltration basins and injection wells, with important applications in sustainable use and management of natural resources. Although the techniques are well established, the technology is not without its operational problems, one of the most common being the decline of recharge capacity over time due to clogging. The study uses drilling samples, groundwater and recycled water from a MAR scheme in the Melbourne area, as well as other reference samples to provide insights into how clogging may affect MAR schemes.
How different geographic areas trigger contrasting thermal clines on lizard populations
Environmental conditions have a direct effect on the biology of animals, especially vertebrate ectotherms, which are intimately dependent on climate to perform their daily activities. During the last few years, many researchers have focused on studying the influence of environmental temperature shifts on various lizard life history traits, as well on evaluating thermophysiological parameters. Nevertheless, an understanding on how different climatic conditions imposed by geography alter the thermal ecology, physiology and behaviour of lizards is still not completely elucidated for most species. The aim of my project is to analyse the differences on the thermal biology of closely related lizard species, and thus provide new insights into the diverse strategies lizards are implementing to endure the climatic conditions in the area they inhabit. Additionally, it will contribute with valuable thermal ecological data that can be employed to assess the state of lizard populations in the face of climate change.
Supervisor: Dr. Richard Peters
Hydrological and vegetation controls upon the Ovens River, southeast Victoria.
My project focuses on terrestrially aged Eucalyptus camaldulensis (River red gum) leaves as a source of bioavailable dissolved organic nitrogen (DON), which I believe has the capacity to act as a valuable nutrient source to in-stream processes, but has received limited attention in the past. After investigating proteins and amino acids from Eucalyptus leaves as a DON source, I have now begun to examine fungi as both a source of and catalyst for the release of DON. I hope that this work will contribute to a greater understanding of freshwater nutrient cycles and food-web dynamics within both floodplain and riverine environments.
Multimodal signalling by the Australian dancing frog, Litoria fallax
Frogs are well known throughout the world for their acoustic communication. But recent studies have drawn our attention to visual signalling behaviour of some frog species. Litoria fallax, or the Eastern dwarf tree frog, is an Australian frog species that has been identified to use multimodal signalling, in which both acoustic and visual signals are part of their complex communication system. Even though the visual display behaviour of this nocturnal species has been previously observed, the actual function of such behaviour is still unknown. Given its broad distribution along the east coast of Australia, this species also provides a good platform to study the geographical variation of the communication behaviour. The aim of my PhD project is to study this complex communication behaviour of Litoria fallax in order to understand the evolutionary function of each communication mode using both field observations and experimental approaches.
Supervisor: Dr Richard Peters
Early victims or hardy survivors? Assessing climate vulnerability and conservation of plant communities on restricted soils
Climate change poses enormous future challenges to Australia’s biodiversity. Understanding how increasing temperature, more frequent droughts, and predicted increases in fire frequency will affect flora is critical to inform appropriate management actions for some of Australia’s rarest species.
Much of the focus of climate change risk to endangered species include those substantially affected by habitat loss, however, the approaches of translocation or composite provenancing do not apply to edaphic specialist plants growing on restricted soil like limestone or serpentine. The vulnerabilities of these specialised plants to increasing global temperatures may be less about fragmentation and more about increasing environmental (mortality-inducing) stress, and the absence of appropriate habitat within dispersal distance to maintain their climate niche. As such, these species may be ‘early victims’ of climate change. Alternatively, plant species in these communities may be ‘hardy survivors’ – they grow on soils that are typically ‘stressful’ to non-adapted species.
The aim of this project is to investigate if plants on restricted geologies are indeed vulnerable to the effects of climate change, or are they hardy survivors? If edaphic specialist endemics are early victims of climate change, we need to quickly develop on-ground strategies to plan for this increased risk. This might include identifying if novel populations could be established (in the long term) and examining how best to maintain these species in situ (over shorter timescales).
Supervisors: John Morgan, Susan Hoebee and Adam Miller
Life in the suburbs: Spatial change in urban bird communities
Increasing urbanisation is a global phenomenon which threatens native biodiversity and contributes to biotic homogenisation. As urban development often occurs close to natural habitats, it has the potential to affect the distribution and abundance of native species, and the overall composition of communities. Knowledge of how urbanisation affects native fauna can assist in planning for more sustainable cities. Jacinta’s project aims to investigate the influence of urban development on bird communities around greater Melbourne. Her study is testing the relative influence of a) extent of tree cover, b) housing density and c) presence of waterways on avian species richness, community composition, and the occurrence of individual species.
Biology, ecology and impact of the introduced Giant pine scale (Marchalina hellenica) on Pinus radiata in Australia.
Giant pine scale is a sap sucking insect native to pine forests of the eastern Mediterranean region, where it feeds primarily on native pine species. Recently, giant pine scale was detected in Melbourne and Adelaide, where it has been feeding on the novel host Pinus radiata, an economically significant tree for Australian timber production. Giant pine scale usually reproduces parthenogenically and secretes thick cotton-like wax. These traits have rendered conventional eradication ineffective, yet effective management strategies are needed to mitigate its impact. The biology and ecology of this insect in Australia is poorly understood, which limits the capacity to predict its pest potential or likelihood of management using biological control.
My Forest and Wood Products Australia (FWPA) funded project seeks to understand the nature of the Giant pine scale’s biology, life history and ecology on its new host and in the Australian environment, to quantify its actual and potential impact on native ecosystems and timber production in Australia, and to provide insights into adaptive strategies and insect-plant interactions of scale insects more broadly.
Supervisors: Assoc. Prof. Martin Steinbauer, Assoc. Prof. Paul Cunningham (Agriculture Victoria) and Dr Angus Carnegie (NSW Department of Primary Industries).
Ecologically relevant sleep-dependent cognition in birds.
Sleep is important for maintaining optimal performance during wakefulness. The dominant venue for sleep research is the laboratory, with a clear focus on the study of inbred strains of rat and mouse. Most work on the role of sleep in memory processing and performance is conducted with mazes and motor-vigilance tasks. However, (a) the laboratory is an overly simplified environment that fails to capture the complexity of natural conditions, (b) inbred rodents themselves are simplified animals, and (c) the cognitive tests used have limited ecological relevance. Little is known about how animals use sleep for maintaining cognitive abilities in the wild.
Advanced cognition is a key trait enhancing the fitness of many wild animals. Maintaining the neural mechanisms for advanced cognition, including specialized memory, is energetically expensive, and is critically dependent on sleep. In addition, sleep also imposes missed-opportunity costs on animals by limiting the time available to perform alternative behaviours. In my PhD, I will study the ecological role of sleep-dependent cognition in the lives of wild birds in Australia and in the USA.
Supervisors: Dr John Lesku, Dr Timothy Roth (Franklin and Marshall College, USA), Prof. John Endler (Deakin University).
The Geomorphology of the Alluvial Megafans of the Northern Victorian Plains
Low-angle alluvial megafans have been observed to extend from the Victorian highlands northward into the Murray Basin. Megafans are defined as large fluvial features formed when a stream exits a mountain range onto a flat plain. Intermittent, high-volume discharge events gradually build up the surface of the fan by depositing successive layers of sediment on the surface. This depositional pattern is facilitated by a network of distributary channels that feeds the different areas of the fan. Due to their very low angle (no more than 0.0009°) and low relief, these features had previously not been identified as alluvial megafans and were instead classified as general channel and flood sediments of the Shepparton Formation, a Pliocene-Holocene aged floodplain formation. Three megafans in particular will be the main focus of this study, and are located along the Loddon River, Campaspe River and Bullock Creek. The aim of my research is to understand the past and present geomorphological processes that contributed to the formation of these megafans. By completing this research, a better understanding of the flood processes of the Victorian Riverine plains will be achieved, in addition to understanding the formation processes of low angle temperate alluvial megafans in a mid-latitude context.
Influence of ontogenetic and environmental factors on the abundance and composition of tannins in Eucalyptus camaldulensis leaves
Tannins are secondary metabolites found in almost all plants. They have a range of functions, e.g. defence (against herbivores, microbes, viruses and competing plants), signalling (attraction of pollinating or seed dispersing animals) and photoprotection (limit damage of photosynthetic apparatus by ultraviolet radiation). The photoprotection hypothesis is controversial because there is a paucity of empirical evidence to counter the widely accepted anti-herbivory explanation. This is especially true for Eucalyptus in which tannins are commonly cited as providing defence against insect and vertebrate herbivores. Using HPLC and mass spectrometry (MS) analysis of glasshouse- and field-grown leaves, I will investigate the putative photoprotective role of tannins in all seven subspecies of Eucalyptus camaldulensis (River red gum). I will relate differences in tannin composition to the distribution of the species across the Australian continent.
Supervisors & collaborator: Assoc. Prof. Martin Steinbauer, Dr Ian Potter (Department of Chemistry and Physics), Dr Simone Rochfort (AgriBio) and Prof. Juha-Pekka Salminen (University of Turku, Finland).
Managing grasslands for the Plains-wanderer (Pedionomus torquatus) and other fauna: Re-introduce fire or maintain livestock grazing?
Victoria’s Northern Plains Grasslands are one of the last remaining strongholds for the critically endangered and evolutionary unique Plains-wanderer (Pedionomus torquatus). These grasslands are currently managed using livestock grazing and fire to promote an open vegetation structure thought to be optimal for the Plains-wanderer. However there has been little study of the mechanisms by which vegetation structure influences the occurrence of Plains-wanderers and other grassland birds. In particular, knowledge of how varying disturbance regimes and resultant vegetation structure influence food availability and foraging patterns is lacking. My research project aims to provide empirical evidence to help guide improved management of Plains-wanderer habitat by investigating habitat requirements and movement ecology of the Plains-wanderer, and identify the effects of livestock and management practices on habitat for grassland birds.
Supervisors: Assoc. Prof. John Morgan, Dr Steve Leonard, Dr David Baker-Gabb (external)
Sleep evolution: pharmacological, electrophysiological, biochemical and comparative perspectives.
Sleep is a much-studied behaviour across animals, with humans spending roughly one-third of their lives in this vulnerable state. But where did it all start? My research looks at the evolutionary origins of sleep. My main research group is platyhelminth flatworms – a phylum that appeared 800 million years ago - to determine whether the processes that maintain and regulate sleep in humans is shared between distantly-related animals. To do this, I use a combination of behavioural, pharmacological, biochemical, and electrophysiological techniques. I will also be using the flatworms' extraordinary ability to regenerate their complete brain to study the potential differences between naïve and ‘lab-grown’ sleep behaviour. The final part of my PhD will be to characterise sleep in sea cucumbers, close relatives of the Chordate phylum, to further understand the evolutionary pathway of sleep. Collectively, these studies will provide insight into when, why, and how sleep first appeared.
Ecological lessons from Djaara women returning food plants to Country
Despite the obvious overlap between aspirations of First Nations Australians to heal Country and the goals of restoration ecologists, there have been few projects seeking to co-produce knowledge on healing/restoration between scientists and Traditional Custodians in SE Australia.
My project, which is part of a research partnership between La Trobe University and Dja Dja Wurrung Clans Enterprises, asks how important women’s cultural plants can be re-established or made more abundant through culturally informed practices on Dja Dja Wurrung Country. I am working closely with a Dja Dja Wurrung Women’s Knowledge Group using a participatory action research method.
In addition to building knowledge of the factors influencing (re)establishment success of the plants, I aim to use the unique opportunity of this collaboration and the participatory method to explore the dimensions of culturally informed ecological research. There are likely wider implications for informing ecological restoration (healing Country) in a post-colonial landscape.
Remote Sensing evapotransiration in Blue Gum plantations
Rakhshan is modelling for remote sensing evapotranspiration estimate to constrain groundwater contributions to catchment water balances in western Victoria. Evapotranspiration is an essential component of the hydrological balance. For field measurements of ET, various techniques are used. Although point data can be extrapolated, the reliability over large areas is uncertain. To overcome this limitation, a Surface Energy Balance Algorithms for Rainfed Agriculture (SEBARA) is developed and the satellite data, at a spatial resolution of 30 x 30m, is used to estimate the spatial pattern of evapotranspiration.
Extensive blue gum (Eucalyptus globulus) plantations have been established in SW Victoria which have impacted the groundwater resources. Her project will help to understand the impact of land use shift on the available water resources.
Supervisor: Assoc. Prof. John Webb
Using personality and cognitive assessment of individuals as a conservation tool for improving reintroduction/translocation success.
Species extinction has reached crisis point globally and the need to develop effective and efficient ways of managing remaining endangered populations is greater than ever. Captive breeding and reintroduction has been identified as a key approach in conservation, however the success of such programs is debatable with survival after release being low. The choice of candidates for release is often based on age, sex and health status, however, there is growing recognition that an individual’s behavioural type is related to fitness and hence may be important to survival success. While the existence of different personality traits within and between animal populations has been relatively well established, the application of this variation to reintroduction programs has been neglected.
The key aim of my PhD is to establish if personality and cognitive assessment of individuals can be used as a conservation tool for improving reintroduction/translocation success. Findings from my research will inform recovery teams on the release of individuals with traits linked to increased survival.
Assessment of eucalypts by Glycaspis species of psyllid: quantifying the roles of phytochemical and physical traits on host acceptance
Lerp-forming psyllids in the megadiverse genus Glycaspis (Hemiptera: Aphalaridae) are important components of Australia’s biodiversity but one in particular (Glycaspis brimblecombei) is also an economically important pest overseas. My project will focus on G. brimblecombei and Glycaspis sp. n. ex. Eucalyptus leucoxylon which differ in host breadth, i.e. G. brimblecombei is oligophagous (in Australia it has been recorded from seven species and from E. tereticornis in Uruguay) while Glycaspis sp. n. is apparently monophagous (recorded from E. leucoxylon on which it co-occurs with G. brimblecombei). These two species provide an opportunity to investigate how psyllid adaptations to plant secondary compounds and foliar physical characteristics have been associated with changes in host breadth within Glycaspis. My project will address interactions potentially linked to host shifts and divergence of psyllids on Eucalyptus.
Supervisor: Assoc. Prof. Martin Steinbauer
Campbell Van Praagh
The White Hills Gravel throughout Central Victoria
The White Hills Gravel is an Early Tertiary fluvial gravel, deposited some 55 – 68 million years ago, that is preserved as remnants throughout much of northwestern and north-central Victoria. The distribution and properties of these river gravels suggest that they were deposited during high-energy chaotic floods that affected a large area across Victoria. Campbell’s research aims to improve upon the previous mapping of the White Hills Gravel across these areas, and reconstruct the likely pathways of the ancient rivers that deposited them. Campbell will also interpret aspects of the Early Tertiary landscape and climate of Victoria through analysis of the gravels, and endeavour to identify less-prominent faults within the landscape that may have been missed within previous geological mapping. The project involves a significant component of field work, and the use of GIS software to store and analyse the collected data.
The evolution of mammal pollination in the south-west Australian biodiversity hotspot and its vulnerability to landscape modification
Mammals are known to contribute to pollination of diverse plant genera across Australia. However, there is little evidence for pollination systems specialized on mammal pollination. Many of the western Australian banksias in the Dryandra series have unusual prostrate inflorescences that appear adapted to pollination by flightless mammals, particularly, the honey possum. My research will test for specialisation on mammal pollination in members of Dryandra using a combination of methods of behavioural ecology, population genetics, species observation and exclusion experiments, and phylogenetic analyses. I will investigate the resilience of this pollination strategy to landscape modification by identifying any environmental threats to the continued interaction of honey possums and dryandras.
The expected outcomes of this study will be improved understanding of the evolution of mammal pollination of dryandras. The study will also aid land managers through better understanding of the key threats of this remarkable ecological interaction.
Reproductive sleeplessness in dasyurid marsupials
Sleep is a prominent part of animal life, but our understanding of the adaptive value of sleep remains incomplete. Even though it is generally accepted that reduced performance is an evolutionary outcome of sleeplessness, some animals may perform well on little sleep when ecological demands favour extended periods of wakefulness. My project examines the activity patterns of dasyurid marsupials in lab-based and semi-wild environments, and quantifies the concentration of various hormones that may predict activity levels. Furthermore, to provide insight into sleep evolution and function, my research seeks to determine whether the most active males sire more offspring.
Supervisor: Dr John Lesku