Kimberley Simpson

Research

At a broad scale I’m interested in how processes (natural and artificial) create and maintain biological diversity, but also how this diversity feeds back to influence these processes too. With a focus on plants, I combine experimental approaches, field observation and analysis of big data to address questions about factors that create plant diversity across space and time, and the future of plant diversity in the Anthropocene.

I'm particularly interested in the bi-directional relationship between fire and grasses, and how this will change in the future. Grasses fuel the vast majority (>80%) of wildfires on Earth, and influence fire behaviour through their traits (Simpson et al., 2016). These traits differ between species meaning that communities dominated by different species have very different flammabilities. In turn, fire regime plays an important role in determining grass traits at community-to-global scales (Simpson et al., 2019; Simpson et al., 2021).

I'm currently investigating the roles the of abiotic (CO₂ concentration, water availability) and biotic factors (tree and grass functional traits) in woody encroachment in savannas. An increase in woody biomass is seen across much of the world's savannas, and is causing ecosystem degradation (erosion of ecosystem services such as the provision of food, water and opportunities for eco-tourism for hundreds of millions of rural and urban people). This project focuses on the root cause of this transformation of savannas, aiming to resolve fundamental unknowns about global change drivers, especially how rising atmospheric CO₂ interacts with water availability. This project involves extensive experimental and field work with our collaborators Prof. Brad Ripley, Dr Sarah Raubenheimer (Rhodes University, South Africa), Dr Caroline Lehmann (Royal Botanic Garden Edinburgh) and Dr Nicola Stevens (University of Oxford).

You can watch to me talk about my research (as of early 2021) below if interested :) Thanks!

Select publications

Simpson KJ, Archibald S, Osborne CP. 2022. Savanna fire regimes depend on grass trait diversity. Trends in Ecology and Evolution 37: 749-758 - Link to paper -

Liu H, Simpson KJ, Ye Q, Cui E, Xia J. 2022. Can evolutionary history predict plant plastic responses to climate change? New Phytologist 235: 1260-1271 - Link to paper -

Harrison SP, Prentice IC, Bloomfield KJ, Dong N, … Simpson KJ. 2021. Understanding and modelling wildfire regimes: an ecological perspective. Environmental Research Letters 16: 125008 - Link to paper -

Raubenheimer SL, Simpson KJ, Carkeek R, Ripley BS. 2021. Could CO₂-induced changes to C₄ grass flammability aggravate savanna woody encroachment? African Journal of Range & Forage Science 39: 82-95 - Link to paper -

Simpson KJ, Atkinson RR, Mockford EJ, Bennett C, Osborne CP, Rees M. 2021. Large seeds provide an intrinsic growth advantage that depends on leaf traits and root allocation. Functional Ecology 35: 2168–2178 - Link to paper - Link to accessible summary -

Simpson KJ, Jardine EJ, Archibald S, Forrestel E, Lehmann CER; Thomas G, Osborne CP. 2021. Resprouting grasses are associated with less frequent fire than seeders. New Phytologist 230: 832-844 - Link to paper - Link to commentary on this paper -

Brightly WH, Hartley SE, Osborne CP, Simpson KJ, Strömberg CAE. 2020. High silicon concentrations in grasses are linked to environmental conditions and not associated with C₄ photosynthesis. Global Change Biology 26: 7128– 7143 - Link to paper -

Simpson KJ, Bennett C, Atkinson RRL, Mockford EJ, McKenzie S, Freckleton RP, Thompson K, Rees M, Osborne CP. 2020. C₄ photosynthesis and the economic spectra of leaf and root traits independently influence growth rates in grasses. Journal of Ecology 108: 1899-1909 - Link to paper -

Simpson KJ, Olofsson JK, Ripley BS, Osborne CP. 2019. Frequent fires prime plant developmental responses to burning. Proceedings of the Royal Society B 286: 20191315 – Link to paper – Link to related article on The Conversation

Simpson KJ, Wade RN, Rees M, Osborne CP, Hartley SE. 2017. Still armed after domestication? Impacts of domestication and agronomic selection on silicon defences in cereals. Functional Ecology 31: 2108-2117 – Link to paper – Link to accessible summary -

Simpson KJ, Ripley BS, Christin P-A, Belcher CM, Lehmann CER, Thomas GH, Osborne CP. 2016. Determinants of flammability in savanna grass species. Journal of Ecology 104: 138-148 – Link to paper –

Education & Experience

2021 - Present: Research Associate (Honorary Appointment), Botany Department, Rhodes University, South Africa

2019 - Present: Postdoctoral Researcher, University of Sheffield

Project: ‘How do global change and functional traits influence savanna woody plant encroachment? (Jan 2020 - Present)

Project: 'Does physiological innovation change the fundamental relationships between growth and survival?’ (April 2019 - Jan 2020)

2017 - 2019: Associate Lecturer, Biology Dept., University of York, UK

2017: University Teacher, Dept. Animal & Plant Sciences, University of Sheffield, UK

2013 - 2018: PhD, Dept. Animal & Plant Sciences, University of Sheffield, UK (supervised by Colin Osborne and Gavin Thomas) - Link to PhD thesis -