I also apologise for a bit of silence over the past week. After coming back from the ESP Conference in Portland, I’m now back at Stanford University working with Paul Ehrlich trying to finish our book (no sneak peaks yet, I’m afraid). I have to report that we’ve completed about about 75 % it, and I’m starting to feel like the end is in sight. We hope to have it published early in 2013.
So here they are – the latest 9 PhD offerings from us at the Global Ecology Laboratory. If you want to get more information, contact the first person listed as the first supervisor at the end of each project’s description.
1. Optimal survey and harvest models for South Australian macropods (I’ve advertised this before, but so far, no takers):
The South Australia Department of Environment, Water and Natural Resources (DEWNR) is custodian of a long-term macropod database derived from the State’s management of the commercial kangaroo harvest industry. The dataset entails aerial survey data for most of the State from 1978 to present, annual population estimates, quotas and harvests for three species: red kangaroo (Macropus rufus), western grey kangaroo (Macropus fuliginosus), and the euro (Macropus robustus erubescens).
DEWNR wishes to improve the efficiency of surveys and increase the precision of population estimates, as well as provide a more quantitative basis for setting harvest quotas.
We envisage that the PhD candidate will design and construct population models:
- to predict population size/densities with associated uncertainty, linking fluctuations to environmental variability (including future climate change projections)
- to evaluate the efficiency of spatially explicit aerial surveys
- to estimate demographic parameters (e.g., survival rate) from life tables and
- to estimate spatially explicit sustainable harvest quotas
2. Correcting for the Signor-Lipps effect
The ‘Signor-Lipps effect’ in palaeontology is the notion that the last organism of a given species will never be recorded as a fossil given the incomplete nature of the fossil record (the mirror problem is the ‘Jaanusson effect’, where the first occurrence is delayed past the true time of origination). This problem makes inference about the timing and speed of mass extinctions (and evolutionary diversification events) elusive. The problem is further complicated by the concept known as the ‘pull of the recent’, which states that the more time since an event occurred, the greater the probability that evidence of that event will have disappeared (e.g., erased by erosion, hidden by deep burial, etc.).
In a deep-time context, these problems confound the patterns of mass extinctions – i.e., the abruptness of extinction and the dynamics of recovery and speciation. This PhD project will apply a simulation approach to marine fossil time series (for genera and families, and some individual species) covering the Phanerozoic Aeon, as well as other taxa straddling the K-T boundary (Cretaceous mass extinction). The project will seek to correct for taphonomic biases and assess the degree to which extinction events for different major taxa were synchronous.
The results will also have implications for the famous Sepkoski curve, which describes the apparent logistic increase in marine species diversity over geological time with an approximate ‘carrying capacity’ reached during the Cenozoic. Despite recent demonstration that this increase is partially a taphonomic artefact, a far greater development and validation/sensitivity analysis of underlying statistical models is needed to resolve the true patterns of extinction and speciation over this period.
The approach will be to develop a series of models describing the interaction of the processes of speciation, local extinction and taphonomic ‘erasure’ (pull of the recent) to simulate how these processes interact to create the appearance of growth in numbers of taxa over time (Sepkoski curve) and the abruptness of mass extinction events. The candidate will estimate key parameters in the model to test whether the taphonomic effect is strong enough to be the sole explanation of the apparent temporal increase in species diversity, or whether true diversification accounts for this.
3. Genotypic relationships of Australian rabbit populations and consequences for disease dynamics
Historical evidence suggests that there were multiple introduction events of European rabbits into Australia. In non-animal model weed systems it is clear that biocontrol efficacy is strongly influenced by the degree of genetic diversity and number of breed variants in the population.
The PhD candidate will build phylogenetic relationships for Australian rabbit populations and develop landscape genetic models for exploring the influence of myxomatosis and rabbit haemorrhagic disease virus (RHDV) on rabbit vital rates (survival, reproduction and dispersal) at regional and local scales. Multi-model synthesis will be used to quantify the relative roles of environment (including climate) and genotype on disease prevalence and virulence in rabbit populations.
4. Spatio-temporal drivers of rabbit life-history traits and its influence on the efficacy of rabbit control in Australia
Identifying general patterns of how, and in which situations, demographic rates vary across space and time, is necessary to understand the true population dynamics of a species.
The PhD candidate will do a focused meta-analysis of rabbit demographic studies, combined with separate spatial information on climate, land use and disease. The meta-analysis will be supported by a survey of Australian rabbit disease and biology experts, to elicit expert (prior) knowledge of key drivers of rabbit demographic rates and disease dynamics. Bayesian and information-theoretic statistical approaches, informed by expert opinion and controlling for disease, will be used to determine the main environmental predictors of rabbit demographic rates. Data on sensitivity to different demographic traits (e.g., age-specific survival and reproductive rates) and particular environmental conditions (e.g., drought) will be integrated into individual-based, spatially oriented demographic models.
5. Range dynamics and demographics of spatially structured reptile populations under global change
Distributional range margins, for the majority of species, end at seemingly arbitrary boundaries. We will develop a demographic framework to characterise the edge-of-the-range dynamics of a variety of reptiles by examining combinations of intrinsic and extrinsic factors thought to limit geographic extent.
The PhD candidate will exploit advanced statistical and computational approaches to integrate multiple lines of information on the drivers of range and abundance in turtles, skinks and geckos using detailed long-term data sets. The results will provide generalisations on how geographic range size and structure change through time in response to global change and deliver a new toolbox for exploring trade-offs inherent in conservation planning.
6. Determining the influence of global change on turtle biodiversity in Australia
Global warming is forecast to influence turtle fauna through local and regional climate change and synergies with other human-induced drivers of environmental change.
The PhD candidate will use comprehensive occurrence and molecular databases and spatial information on climate and environmental variation to identify how turtle biodiversity changes spatially, and the important drivers of that change. Community composition models will be used to project changes in turtle diversity under future scenarios of climate and land-use change. In particular the student will explore the relationship between increasing demand for water and climate change, and its potential influence on turtle fauna. Results and associated models will provide important insights into future turtle conservation management in Australia and beyond.
7. Exotic vertebrate risk analysis and invasion pathway modelling
The successful candidate will collect up-to-date datasets on the identities and abundances of exotic vertebrate ornamental fish species in retail, private, and public Australian collections, as well as at large in the environment. The student should have strong statistical and/or mathematical skills and be capable of developing novel computational tools for calculating species incursion risks and constructing invasion pathway networks. The model outputs will be used to predict the specific supply regions, transport modes, user groups, and taxa that pose the greatest risk to the entry and establishment of new pest populations in Australia.
8. The role of rabbit and virus genetics in the development of resistance to rabbit haemorrhagic disease virus (RHDV)
The European rabbit is a major pest animal in Australia. The successful PhD candidate will conduct both field and laboratory research to understand resistance to RHDV including age related factors, possible interactions with myxomatosis, and virus and rabbit genetics. The candidate will have access to epidemiological, serological, tissue, genetic, morphological and population dynamics data from an ongoing 16 year research project centred on an isolated rabbit population located 70 kilometres north of the City of Adelaide, South Australia.
9. Rabbit haemorrhagic disease virus: mechanisms of transmission
The aim of this project is to develop a greater understanding of the interactions between rabbits, RHDV and the environment. Topics such as virus persistence, outbreak dynamics, and modes of transmission will be investigated. The student should have broad ecological skills with an epidemiology background. The PhD will be based at both the University of Adelaide and the Vertebrate Pest Research Unit in Orange, NSW.