PhD position at Leeds: Floristic dynamics in tropical forests
Julkaistu 2012-02-07 10:17:00PhD project starting September 2012: “Floristic dynamics in tropical forests”
Ecology and Global Change, University of Leeds
Oliver Phillips, with Tim Baker, Simon Lewis, Antje Ahrends (Edinburgh), Kyle Dexter
Amazonia and Africa still have huge areas of mature forest, home to thousands of tree species and responsible for a large fraction of the earth’s primary production. Both regions also face multiple environmental pressures; beyond the simple removal of forest, these include changing environment (eg temperature, moisture, nutrients), external disturbances (eg logging, fire), and internal dynamics (eg changing mortality). Our research has shown that mature forest in both continents is not in equilibrium, as they have been recently contributing a net sink from the atmosphere to the forest of nearly a billion tonnes of carbon per year (eg Baker et al. 2004, Phillips et al. 2009, Lewis et al. 2009). The productivity of Amazon forests has also increased (Lewis et al. 2004). Yet the causes of these changes in intact forests remains unclear, and recent droughts in Amazonia have now accelerated mortality. What is happening to the species and functional composition of these supposedly ‘intact’ forests as a result remains unknown.
Which kinds of trees may be winning? Which losing? Where? and Why? This project is an opportunity for a quantitatively-oriented student to make a distinct contribution to global change biology, while working with a large international research team dedicated to understanding and predicting the behaviour of Amazon forest ecology, and in particular in understanding which species are most at risk. The research is funded through a new European Research Council Advanced Grant, starting in 2012. You will join a team tackling the question of how remaining tropical forests are responding to their changing physical environment. The PhD project itself will draw on decades of forest dynamics and compositional data from our unique networks of long-term plots in Amazonia and Africa, and new insights into Amazon phylogeography from simultaneous NERC and NSF projects which are led jointly by Edinburgh and Leeds.
Aims and Objectives
The overall aim of this project is to understand better how and why Amazon and African forests are changing internally, in terms of floristic and functional composition.
This will require (1) characterising the tree taxa in each forest bloc by their spatial distribution and density, (2) quantifying their likely preference for different environmental factors, such as drier climates or nutrient-rich soils, and (3), using the newly derived knowledge of species’ responses to different resources to explore patterns of recent functional shifts in the biological community.
Approach and Methods
The project is based on our large and growing international networks of permanent plot monitoring across the tropics. We are assembling a database of hundreds of plots, with long-term forest dynamics, soils, and plant distribution and traits described. This will be your primary source for this research.
There is flexibility in how this project can be developed; here is a suggested approach:
1. Assess the affiliation of tree families, genera, and species to climate and soil factors, using their abundance-weighted distribution across hundreds of sample plots in Amazon and African forests (biogeographic analysis).
2. Apply more sophisticated ecological niche modelling techniques that can account for potential covariation and spatial autocorrelation. The object here will be to generate a preference profile for each taxon, showing its occurrence probability across soils and climate in each continent.
3. Test for recent floristic change in both Amazon and African forests. Using the new estimators of species’ responses to different resources and/or environment, you can explore the spatial and environmental pattern of recent functional shifts in the biological community. For example, if there is a trend toward trees that require less moisture, then when did that change occur? Are changes in the dominance of these species greatest where drying is strongest? It will also be possible to focus simply on mortality and new tree recruits, as this may indicate not only recent changes, but will give insight into the future functional trajectory of the ecosystem.
As part of the project there will be opportunities to participate in field work in long-term monitoring plots in Africa, but the main focus of the work will be statistical analysis of biogeographic pattern and ecological changes using the unique databases we are building.
Baker, T.R. et al. 2004. Increasing biomass in Amazonian forest plots. Philosophical Transactions of the Royal Society, Series B 359: 353-365.
Lewis, S.L. et al. 2004. Concerted changes in tropical forest structure and dynamics: evidence from 50 South American long-term plots. Philosophical Transactions of the Royal Society, Series B 359: 421-436.
Lewis, S.L. et al. 2009. Increasing carbon storage in intact African tropical forests. Nature 477: 1003-1006.
Phillips, O.L. et al. 2009. Drought sensitivity of the Amazon rainforest. Science 323: 1344-1347.
This project is fully funded, including the student stipend. The supervisors co-ordinate a pan-Amazon network of forest researchers (RAINFOR), and a similar initiative in Africa (AfriTRON). Together with colleagues worldwide we are monitoring tree growth and mortality, as well as species composition, of tropical forests in more than 400 locations, many of which have had thorough soil sampling data too. We have developed the tools to manage these permanent plot data (www.forestplots.net), and a modelling-environment to explore the effects of environmental change on forest dynamics (forest dynamics simulator, Fyllas et al. in prep.). In using these unique resource this project will leverage recent and active funding to our group of more than £5million (Moore Foundation, NERC Consortia, Royal Society, EU); the new ERC project that this PhD opportunity is part of will strengthen the group further. We collaborate closely with colleagues at the Royal Botanical Garden Edinburgh, including Toby Pennington, Antje Ahrends, and Kyle Dexter (the latter shared with Leeds), with specialist expertise in phylogenetics and niche modelling, and at Oxford University (Professor Yadvinder Malhi) with special expertise in ecosystem carbon cycling.
The successful candidate will have some background in advanced statistical analysis (e.g., path analysis, multi-level modelling) or have the ability and strong desire to pick up such skills quickly, as well as some background in ecological theory and techniques. You will be strongly motivated to pursue a career either in academic tropical ecological research or at the intersection of science and forest conservation policy. Candidates with an MSc or similar advanced degree in Biology, Ecology, or a strongly mathematical/ statistical degree, are particularly encouraged to apply.
Deadline for applications: February 13th.