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Dr Stephen Woodcock

Biography

Stephen joined UTS in 2010 as a Lecturer in the School of Mathematical Sciences. Prior to this, he was a Research Associate at the University of Glasgow and also worked in private sector consultancy/analysis in London. In addition, he is now an Associate Member of the Plant Functional Biology and Climate Change Cluster (C3) at UTS.

His primary research interests lie in the application of mathematical models to describe biological and ecological systems. The main motivation behind his work is a drive to develop readily implemented solutions and models for pressing real-world problems in the biological and environmental sciences. As such, he works primarily in multidisciplinary teams alongside marine biologists, microbial ecologists and environmental engineers.

His research projects have covered a vast range of applications from improving the design and efficiency of wastewater treatment systems to understanding and modelling the growth of biofilms on riverbeds. Current research topics include modelling the biogeography around the Great Barrier Reef, calibrating and interpreting data from marine fluorescence meters and examining the effect of habitat loss upon fish behaviour in marine parks.

Stephen is a keen and committed teacher and has co-ordinated and taught subjects from the first year undergraduate level through to Honours. He has supervised research students at both the Honours and PhD level. Additional to his main duties at UTS, he is a frequent and enthusiastic contributor to High School outreach programs and widening participation schemes.

Stephen holds a PhD in Civil Engineering from the University of Glasgow (2007) and a MMath in Mathematics from the University of Oxford (2003).

Professional

Memberships/Committee Roles:

ANZIAM (Australian and New Zealand Industrial and Applied Mathematics) Engineering Mathematics Group Committee member

Lecturer, School of Mathematical Sciences
Associate Member, Plant Functional Biology & Climate Change
MMath(Oxon), Ph D
 
Phone
+61 2 9514 7602
Room
CB01.15.45
Can supervise: Yes

Lecturing and Co-Ordination:

35101: Introduction to Linear Dynamical Systems

35363: Stochastic Models

Mathematical Ecology and Biology (Honours reading subject)

Teaching and Learning Roles:

Program Director for School of Mathematical Sciences Honours students (BMathFin(Hons) and BSc(Hons)

Chair of School of Mathematical Sciences Honours Subcommittee

Program Director for BSc undergraduate students (Mathematical Sciences Foundation Stream)

Member of School of Mathematical Sciences Teaching and Learning Committee

Teaching and Learning Grants:

Slipping Between the Cracks? Maximising the Effectiveness of Prerequisite Paths (Vice-Chancellor's Learning and Teaching Small Grant 2013, in conjunction with Stephen Bush)

Journal Articles

Woodcock, S.M. & Bush, S.A. 2014, 'Slipping between the cracks? Maximising the effectiveness of prerequisite paths in UTS mathematics degrees', ANZIAM Journal, vol. 55, no. EMAC2013, pp. C297-C314.
Woodcock, S.M., Besemer, K., Battin, T.J., Curtis, T.P. & Sloan, W.T. 2013, 'Modelling the effects of dispersal mechanisms and hydrodynamic regimes upon the structure of microbial communities within fluvial biofilms', Environmental Microbiology, vol. 15, no. 4, pp. 1216-1225.
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The spatial distribution of microbial taxa is determined primarily by physical and chemical environments and by dispersal. In a homogeneous landscape with limited dispersal, the similarity in abundance of taxa in samples declines with separation distance. We present a one-dimensional model for the spatial autocorrelation in abundances arising from immigration from some remote community and dispersal between environmentally similar landscape patches. Spatial correlation in taxa abundances were calculated from biofilms from the beds of two flumes which differed only in their bedform profiles; one flat and the other a periodic sawtooth shape. The hydraulic regime is approximately uniform over the flat bed, whereas the sawtooth induces fast flow over the peaks and recirculation in the troughs. On the flat bed, the correlation decline between samples was reproduced by a model using one biologically reasonable parameter. A decline was apparent in the other flume; however, a better fit was achieved when dispersal was not assumed constant everywhere. However, analysis of finer-resolution data for the heterogeneous flume suggested even this model did not adequately capture the community's complexity. We conclude that hydrodynamics are a strong driver of taxa-abundance patterns in stream biofilms. However, local adaptability must also be considered to build up a complete mechanistic model.
Woodcock, S.M., Van der Gast, C.J., Bell, T., Lunn, M., Curtis, T.P., Head, I. & Sloan, W.T. 2007, 'Neutral assembly of bacterial communities', FEMS Microbiology Letters, vol. 62, no. 2, pp. 171-180.
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Two recent, independent advances in ecology have generated interest and controversy: the development of neutral community models (NCMs) and the extension of biogeographical relationships into the microbial world. Here these two advances are linked by predicting an observed microbial taxa+volume relationship using an NCM and provide the strongest evidence so far for neutral community assembly in any group of organisms, macro or micro. Previously, NCMs have only ever been fitted using species-abundance distributions of macroorganisms at a single site or at one scale and parameter values have been calibrated on a case-by-case basis. Because NCMs predict a malleable two-parameter taxa-abundance distribution, this is a weak test of neutral community assembly and, hence, of the predictive power of NCMs. Here the two parameters of an NCM are calibrated using the taxa-abundance distribution observed in a small waterborne bacterial community housed in a bark-lined tree-hole in a beech tree. Using these parameters, unchanged, the taxa-abundance distributions and taxa+volume relationship observed in 26 other beech tree communities whose sizes span three orders of magnitude could be predicted. In doing so, a simple quantitative ecological mechanism to explain observations in microbial ecology is simultaneously offered and the predictive power of NCMs is demonstrated.
Sloan, W.T., Woodcock, S.M., Lunn, M., Head, I. & Curtis, T.P. 2007, 'Modeling taxa-abundance distributions in microbial communities using environmental sequence data', Microbial Ecology, vol. 53, no. 3, pp. 443-455.
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We show that inferring the taxa-abundance distribution of a microbial community from small environmental samples alone is difficult. The difficulty stems from the disparity in scale between the number of genetic sequences that can be characterized and the number of individuals in communities that microbial ecologists aspire to describe. One solution is to calibrate and validate a mathematical model of microbial community assembly using the small samples and use the model to extrapolate to the taxa-abundance distribution for the population that is deemed to constitute a community. We demonstrate this approach by using a simple neutral community assembly model in which random immigrations, births, and deaths determine the relative abundance of taxa in a community. In doing so, we further develop a neutral theory to produce a taxa-abundance distribution for large communities that are typical of microbial communities. In addition, we highlight that the sampling uncertainties conspire to make the immigration rate calibrated on the basis of small samples very much higher than the true immigration rate. This scale dependence of model parameters is not unique to neutral theories; it is a generic problem in ecology that is particularly acute in microbial ecology. We argue that to overcome this, so that microbial ecologists can characterize large microbial communities from small samples, mathematical models that encapsulate sampling effects are required
Sloan, W.T., Lunn, M., Woodcock, S.M., Head, I., Nee, S. & Curtis, T.P. 2006, 'Quantifying the roles of immigration and chance in shaping prokaryote community structure', Environmental Microbiology, vol. 8, no. 4, pp. 732-740.
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Naturally occurring populations of bacteria and archaea are vital to life on the earth and are of enormous practical significance in medicine, engineering and agriculture. However, the rules governing the formation of such communities are still poorly understood, and there is a need for a usable mathematical description of this process. Typically, microbial community structure is thought to be shaped mainly by deterministic factors such as competition and niche differentiation. Here we show, for a wide range of prokaryotic communities, that the relative abundance and frequency with which different taxa are observed in samples can be explained by a neutral community model (NCM). The NCM, which is a stochastic, birth+death immigration process, does not explicitly represent the deterministic factors and therefore cannot be a complete or literal description of community assembly. However, its success suggests that chance and immigration are important forces in shaping the patterns seen in prokaryotic communities.
Woodcock, S.M., Curtis, T.P., Head, I., Lunn, M. & Sloan, W.T. 2006, 'Taxa-area relationships for microbes: the unsampled and the unseen', Ecology Letters, vol. 9, no. 7, pp. 805-812.
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The recent observation of a power+law relationship, S ? Az, between number of taxa, S, and area, A, for microbial eukaryotes and bacteria suggests that this is one of the few generic relationships in ecology, applicable to plants, animals and microbes. However, the rate of increase in the number of species with area varies from approximately the fourth (z = 0.26) to as little as the 50th root (z = 0.0019) in microbes. This is an enormous range for which no quantitative explanation has been proffered. We show by sampling from synthetic populations that the disparity between sample and community sizes in microbial community surveys means z can be considerably underestimated and accrual of rare taxa with increasing area will not be detectable. Significant microbial taxa+area relationships will only be observed when changes in community structure within samples correlate with area. Thus, the very low z values observed recently cannot be used as the sole evidence in support of any particular community theory of community assembly. More generally, this suggests that our search for patterns and laws in the microbial world will be profoundly influenced and, potentially distorted by the sample sizes that are typical of microbial community surveys.
Curtis, T.P., Head, I., Lunn, M., Woodcock, S.M., Schloss, P.D. & Sloan, W.T. 2006, 'What is the extent of prokaryotic diversity?', Proceedings Of The Royal Society Of London Series..., vol. 361, no. 1475, pp. 2023-2037.
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The extent of microbial diversity is an intrinsically fascinating subject of profound practical importance. The term `diversity+ may allude to the number of taxa or species richness as well as their relative abundance. There is uncertainty about both, primarily because sample sizes are too small. Non-parametric diversity estimators make gross underestimates if used with small sample sizes on unevenly distributed communities. One can make richness estimates over many scales using small samples by assuming a species/taxa-abundance distribution. However, no one knows what the underlying taxa-abundance distributions are for bacterial communities. Latterly, diversity has been estimated by fitting data from gene clone libraries and extrapolating from this to taxa-abundance curves to estimate richness. However, since sample sizes are small, we cannot be sure that such samples are representative of the community from which they were drawn. It is however possible to formulate, and calibrate, models that predict the diversity of local communities and of samples drawn from that local community. The calibration of such models suggests that migration rates are small and decrease as the community gets larger. The preliminary predictions of the model are qualitatively consistent with the patterns seen in clone libraries in `real life+. The validation of this model is also confounded by small sample sizes. However, if such models were properly validated, they could form invaluable tools for the prediction of microbial diversity and a basis for the systematic exploration of microbial diversity on the planet.

Reports

Woodcock, S.M. & Cheung, B. 2010, 'Consumer decisions, information and understanding - A behavioural economics perspective', Decision Technology Ltd, London, pp. 1-63.
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