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B339: Investigating the roles of animal-plant interactions for ecosystem dynamics (Lead Supervisor: Andrew Friend, Geography)

Supervisors: Andrew Friend (Geography) and Michael Harfoot (UNEP-WCMC)

Importance of the area of research:

Interactions between biogeochemistry and ecosystem dynamics influence ecosystems worldwide; e.g. the structure and productivity of plant communities is primarily determined by the interaction between resource availability (e.g. light, nutrients and water on land) and top-down forces (e.g. herbivory or other mortality processes). Grazing pressure is in-turn modulated by trophic interactions (predation) and shifts in plant nutrition (defences, composition). Animal consumers also redistribute the high concentrations of nutrients accumulated within their bodies. Through these processes animals affect the distribution of nutrients in terrestrial ecosystems spatially and temporally.

However, we currently have a very limited understanding of the strength of these feedbacks. Critically, this limits our ability to predict the future of the natural world under global change. For example, the nutritional quality of leaves could decrease as the climate and atmospheric CO2 changes, impacting herbivore feeding rates, growth rates and population dynamics with potential consequences for nutrient cycling, pest outbreaks, vegetation states (such as savanna vs woodland systems) and ecosystem productivity.

Project summary:

Future predictions of ecosystem states and carbon cycling under global change are incomplete as they do not currently take into account interactions between animals and plants. There is substantial evidence that animals influence the distribution of nutrients spatially and temporally and that through this, and their grazing of plants, they influence the composition of plant communities in many ecosystems.

This project will explore the empirical evidence for the importance of non-microbial animals in nutrient cycling and employ state-of-the-art models to explore how including interactions between animals and plants affect future projections of the earth system.

What the student will do:

The initial part of the project will involve reviewing literature to build quantitative databases of empirical evidence relating to the role of animals in nutrient cycling. For example: organismal stoichiometry, whole ecosystem nutrient cycling rates, plant nutrient composition under different environmental conditions and the effects of altered plant nutrients on herbivore ecology will be quantified.

In the second phase these empirical data will be used to develop explorative system-modelling studies that explore the standing stocks of nutrients in animals and plants and the potential effects of global change on these.

Finally, mechanistic implementations of the key interactions uncovered from the first two phases will be encoded in state-of-the-art models of plants (‘Hybrid’) and animals (‘Madingley’) to explore how incorporating ecological interactions between animals and plants affects future projections of plant dynamics, carbon and nitrogen cycling and ecosystem structure and function.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.


Couture, J.J., Meehan, T.D., Kruger, E.L. and Lindroth, R.L., 2015. Insect herbivory alters impact of atmospheric change on northern temperate forests. Nature plants, vol. 1, pp.1 – 5, DOI: 10.1038/NPLANTS.2015.16.

Friend, A.D. and White, A., 2000. Evaluation and analysis of a dynamic terrestrial ecosystem model under preindustrial conditions at the global scale. GLOBAL BIOGEOCHEM CY, v. 14, p.1173-1190. doi:10.1029/1999GB900085

Harfoot, M.B., Newbold, T., Tittensor, D.P., Emmott, S., Hutton, J., Lyutsarev, V., Smith, M.J., Scharlemann, J.P. and Purves, D.W., 2014. Emergent global patterns of ecosystem structure and function from a mechanistic general ecosystem model. PLoS Biol, vol. 12, p.e1001841. doi:10.1371/journal.pbio.1001841.

Follow this link to find out about applying for this project

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