Centre for Behaviour and Evolution

Staff Profile

Dr Isabel Smallegange

Senior Lecturer in Population Biology



I am a senior lecturer in population biology at the University of Newcastle, School of Natural and Environmental Sciences and Group Lead of the Modelling, Evidence and Policy group.

I am also Co-Director of the Newcastle University Centre for Behaviour and Evolution.

I run a research lab that investigates a range of topics that include behavioural ecology, eco-evolutionary dynamics, life history theory, energy budget theory, and demography. We aim to develop a mechanistic framework to link ecology and evolution on the basis of the processes that drive the dynamics of heritable life history traits. The framework is tested in the laboratory using bulb mites Rhizoglyphus robini and using field data, mainly of estuarine and marine ectotherms (tube worms, ray-finned fish, manta rays and sharks). The lab also studies the evolution and maintenance of discrete, alternative phenotypes within single populations of bulb mites R.robini (alternative male morphs). I have blog posts on some of my research results. I also blog about other aspects on life in academia.

Recent publications (see also Publication List)

Smallegange IM, Lucas S. 2024. DEBBIES Dataset to study Life Histories across Ectotherms. Scientific Data 11: 153.

See the Press Release and the blog post at Springer Nature Research Communities.

Rademaker M, van Leeuwen A, Smallegange IM. online. Why we cannot always expect life history strategies to directly inform on sensitivity to environmental change. Journal of Animal Ecology http://doi.org/10.1111/1365-2656.14050

See the blog post at Animal Ecology in Focus.

Prospective students

Please check out the teaching tab for student projects on life history strategies and population responses to environmental change using the DEBBIES dataset, which is described in this manuscript. On the teaching tab, there is also a list of previous under- and postgraduate research projects.

Postdoc opportunities

I’m very happy to support applications for research fellowships, for example Royal Society Newton International Fellowships, Marie Skłodowska-Curie Research Fellowships, Royal Commission for the Exhibition of 1851 Research Fellowships, FCT Post-doctoral Fellowships, etc. I’ve had success in obtaining research fellowships for myself throughout my career so do get in touch if you are interested in bringing a fellowship into my research group.

Current PhD students

- Lukas Edwards (Newcastle University) (I am the main supervisor and Heather Sugden co-supervisor): The eco-evolutionary dynamics of how life histories structure population responses to change through evolving developmental systems.

- Sol Lucas (Newcastle University) (with Per Berggren; I am co-supervisor): Assessing the population dynamics and conservation of sharks in the UK.

- Melissa Versteeg (Newcastle University (with Theresa Rueger; I am co-supervisor): Understanding the long-term effects of abiotic and biotic stressors on the social dynamics and reproduction of anemonefishes.

- Chi-Yen Hsieh (Newcastle University) (with Gary Caldwell; I am co-supervisor): Investigating the effects of malachite green and its metabolites on the microbiome of a marine polychaete worm, Hediste diversicolor.

- Mark Rademaker (NIOZ, Netherlands) (with Anieke van Leeuwen; I am co-supervisor): From pattern to process in modelling the spatiotemporal dynamics of marine communities

Completed PhDs

Marjolein Toorians (2024, UBC, Canada) (with Jonathan Davies; I am co-supervisor): The effect of biodiversity on disease transmission and reservoir-dynamics

- Kim Eustache (2023, University of Perpignan / University of Amsterdam) (with Serge Planes; I was co-supervisor): Unravelling the genetic and environmental influences on blacktip reef shark (Carcharhinus melanopterus) reproductive success

- Naomi Zweerus (2022, University of Amsterdam) (with Astrid Groot; I was co-supervisor): Sexual communication in moths

- Flor Rhebergen (2022, University of Amsterdam): The ecology of adaptive condition-dependent polyphenism

- Tom van den Beuken (2019, University of Amsterdam): How male dimorphisms can be maintained in single populations - a minor's guide to reproduction

- Jacques Deere (2015, Oxford University): Alternative reproductive phenotypes and the role of dispersal in population dynamics; using Rhizoglyphus robini as a model species

Former postdocs

Kathryn Stewart (2017 - 2021) - now Assistant Professor at Leiden University

Jacques Deere (2015 - 2018) - now postdoc at the University of Amsterdam


My full CV with Publication List can be found here. My full list of publications can also be found on Google Scholar.


2022                Senior Fellowship of the Higher Education Academy (UK)

2014                University Teaching Qualification for Lecturers (BKO)

5 Sep 2007     PhD, ‘Interference competition and patch choice in foraging shore crabs

    Netherlands Inst. for Sea Research & University of Amsterdam

2000                BSc, MSc Population Biology, Wageningen University, The Netherlands

Professional history

2022 – present     Senior Lecturer, SNES, Newcastle University, UK

2023 – present     Group Lead, Modelling, Evidence and Policy group, Newcastle University, UK

2022 – present     Co-Director Centre for Behaviour and Evolution, Newcastle University, UK

2019 – present     Visiting scholar, Neth. Inst. for Sea Research (NIOZ), NL

2018 – 2022       Associate Professor, Faculty of Science, University of Amsterdam

2013 – 2018          MacGillavry Fellowship, Faculty of Science, University of Amsterdam

2012 – 2013          Research Fellow at University of Oxford (Dept. of Zoology)

2010 – 2012          Research Fellow at Imperial College London (Silwood Park)

2008 – 2010         Rubicon Fellowship (NWO)– held at Imperial College London

2007 – 2008         A. v Humboldt Fellowship – Max Planck Inst. for Ornithology

2005                      Marie Curie Research Trainee Fellowship – University of Exeter

Maternity leave    Dec 2012 – June 2013

Evidence of international reputation for research

- 2.8M£ (personal) grant money awarded

- >30 invited talks since obtaining my PhD in 2007

- Associate Editor (4 journals; 1 Peer Community): Functional Ecology (since 2018), Oikos (since 2013), Entomologia Experimentalis et Applicata (since 2019), Journal of Animal Ecology (2011-2014); Recommender for PCI Ecology (since 2019)

- Grant reviewer for Austrian Science Fund, Earthwatch, ERC H2020, NERC, ESF-FWO, Norway Research Council, NSF, NWO, Swiss National Science Foundation, The Royal Society

- Manuscript reviewer for >40 journals, including Nature, Nature Ecol & Evol, Scientific Reports

- Invited member of the European Science Foundation College of Expert Reviewers

Research interests

Research conducted within the team ties three research themes:

Eco-evolutionary dynamics, functional trait demography, and developmental plasticity

Climate variability is increasing. How will this affect different animal species? We are in great need of an integrative framework that allows ecologists to predict life history strategies (i.e. the different ways in which individuals trade-off resource investment into survival or reproduction) from functional traits: traits of individuals that inform on the performance of an animal population as a whole. Such a framework is important to inform conservation strategies. Our research takes the mechanistic underpinnings of biological variation as a starting point to extrapolate from life history strategies the responses of populations to future environmental changes. We test this framework mainly on estuarine and marine animals (tube-building worms, ray-finned fish, manta rays and sharks). Our analyses are also part of the DEBBIES project (see Teaching Tab) where we link functional life history traits to population response to environmental change.

For this framework, it is necessary to include eco-evolutionary dynamics, which comprises the understanding of how evolutionary changes (like shifts in genotype and phenotype frequencies) and ecological changes (like the size, composition and growth of an animal population) affect each other. Why? Because for a long time, ecologists ignored evolutionary processes as they were assumed to occur at much longer time scales (thousands to millions of years) compared to ecological processes (days to years). Vice versa, evolutionary biologists ignored ecological processes as these were assumed to occur at such short time scales that their effects would be unnoticeable at the long, evolutionary timescales. However, over the past decades, notions have changed and we now want to understand how ecological and evolutionary variables are both the drivers and the objects of change. Our research aims at formulating and testing predictions on eco-evolutionary population responses to environmental change using long-term population experiments with bulb mites in the lab, and using demographic models parameterised for estuarine and coastal marine species and demographic models. Especially in human-dominated coastal marine environments, we lack understanding of how human activities can impose selection on life history traits like age and size at maturity, and how this affects population dynamics. See for example this special issue on "Eco-Evolutionary Dynamics of Marine Biodiversity in Human-Dominated Coastalscapes", to which the lab contributed.

Finally, the eco-evolutionary process can be significantly influenced by developmental plasticity. Developmental plasticity, whereby a specific input during an individual’s development produces a lasting alteration in phenotype, has been well-documented in human and non-human animals. It is studied by both evolutionary biologists and researchers studying human health. Importantly, developmental plasticity can alter the direction of evolutionary change to the extent that phenotypic variation derived from development becomes encoded in the genome. We aim to unravel the mechanisms and drivers of developmental plasticity using the two male morphs of the bulb mite (Rhizoglyphus robini). Insights gained will increase our understanding of how functional traits affect the eco-evolutionary dynamics of populations, ultimately contributing to a general framework that can be used to accurately predict how populations respond to environmental change, informing conservation strategies. Some first ideas can be found in my recent paper in Trends in Ecology and Evolution.

Other projects the team is involved in

DISCAR: The DISCAR (DIS = disturbance, CAR = carnivores) project aims at providing an operational framework with analytical tools for assessing the impacts of human pressures on populations of small carnivores, and showcasing it with case studies in applied conservation. DISCAR will use small carnivores in French mainland and overseas territories as a case study to assess the population consequences or impacts of human pressures on animal populations.


Modules taught in at Newcastle University

NES2305 Biodiversity, Ecology and Conservation

NES2309 Evolutionary Biology (module leader)

Under- and postgraduate student projects using DEBBIES; a database to compare life history strategies across ectotherms

How can we predict how populations respond to the ever greater changes in their environment? Within this project, we want to know which characteristics of organisms relate to population responses to environmental change. One way to find out is to analyse life history patterns using demographic models. However, depending on whether you model individual life histories from phenomenological descriptions (Salguero-Gomez et al. 2016; Paniw et al. 2018; Capdevila et al 2020) or from mechanistic descriptions using energy budget models (Smallegange et al. in 2020; Smallegange & Berg 2019), different predictions are obtained.

With DEBBIES (Smallegange & Lucas 2024), we aim to to (i) unravel if energy budget descriptions of individual life histories consistently return different predictions on population responses to environmental change compared to when individual life histories are represented by statistical functions, (ii) understand why that is the case, and (iii) identify the most accurate way to predict population responses to novel environmental change. To this end, I support Bachelor, Master and PhD student projects in which students answer their own research questions, while at the same time expanding the DEBBIES database to ultimately conduct large, cross-taxonomical life history analyses.

Do you want to be involved?

If you are a quantitatively driven mind with interests in life history theory, demography, eco­-evolutionary dynamics, or related topics, please contact me to discuss potential graduate or postdoc opportunities in my group.

Students: Below is a list of current and past student projects conducted within the DEB-IPM project. Contact me to discuss research questions you would like to tackle.

Postdoctoral researchers: If you have got a project in mind that you would like to develop in my group, please contact me with a brief project proposal, CV and list of funding themes that you are considering for this project ( e.g. Marie Curie).

Completed DEBBIES student projects

  • Charlotte Rowland: Modelling evolutionary rescue in marine populations: Can life history speed save populations? (2023).
  • Gemma Crawford: There's no time to waste, the fast are winning the race! Comparison in life history speed and IUCN red list for species survival using dynamic energy bdguet integral projection models (DEB-IPM (2023).
  • Jasmijn Hoevers: Demographic analysis to protect declining marine megafaunal populations against environmental changes (2021).
  • Josje Romeijn: A dynamic budget approach to identify a fast-slow life history continuum in microorganisms (2021).
  • Iris van Rijn: Analyzing life history patterns using the Dynamic Energy Budget Integral Projection Model (DEB-IPM) (2021).
  • Dora Vig (MSc student at Utrecht University): Comparison of population-level life-history patterns of invasive marine species, using dynamic energy budget integral projection models, (2021).
  • Sophie Timmerman: On the paradox in dynamic energy budget population models (2019).
  • Gavin Jansen: Predicting changes in population dynamics using stochastic demographic models (2018).
  • Tom Hopman: An analysis of life-history patterns in the fast-slow continuum using dynamic energy budget theory (2018).
  • Naomi Eeltink: Predicting life history patterns across the fast-slow continuum: A cross-level test using the Dynamic Energy Budget-Integral Projection Model (DEB-IPM) (2017).
  • Marjolein Toorians: her BSc project is part of the paper Smallegange et al. (2017) (see below).

Scientific papers resulting from DEBBIES

  • Smallegange IM, Lucas S. 2024. DEBBIES Dataset to study Life Histories across Ectotherms. Scientific Data 11: 153.
  • Rademaker M, van Leeuwen A, Smallegange IM. online. Why we cannot always expect life history strategies to directly inform on sensitivity to environmental change. Journal of Animal Ecology. DOIhttp://doi.org/10.1111/1365-2656.14050 
  • Smallegange IM, Flotats Avilés M, Eustache K. 2020. Unusually paced life history strategies of marine megafauna drive atypical sensitivities to environmental variability. Frontiers in Marine Science 7:597492
  • Smallegange IM, Berg M. 2019. A functional trait approach to identifying life history patterns in stochastic environments. Ecology and Evolution 9: 9350-9361
  • Smallegange IM, Ens HM. 2018. Trait-based predictions and responses from laboratory mite populations to harvesting in stochastic environments. Journal of Animal Ecology 87: 893-905
  • Smallegange IM, Caswell H, Toorians MEM, de Roos AM. 2017. Mechanistic description of population dynamics using dynamic energy budget theory incorporated into integral projection models. Methods in Ecology and Evolution 8: 146-154.

Popular science on DEBBIES

  • Behind the paper blog post at Springer Nature Research Communities (Smallegange & Lucas 2024)
  • Behind the paper blog post at Animal Ecology in Focus (Rademaker et al. 2024)
  • Podcast: Population Biology & Eco-Evolutionary Dynamics From Mites to Manta Rays with Isabel Smallegange
  • Smallegange IM, Berg MP (2020). A slow pace of life makes animals more sensitive to unpredictable climate variations. Amsterdam Science 11:3
  • Smallegange IM. Big data also need big concepts. Biog post September 2019.


Capdevila, P., Beger, M., Blomberg, S. P., Hereu, B., Linares, C., and Salguero-Gómez, R. (2020). Longevity, body dimension and reproductive mode drive differences in aquatic versus terrestrial life history strategies. Funct. Ecol. 34, 1613–1625. doi: 10.1111/1365-2435.13604

Paniw, M., Ozgul, A., and Salguero-Gómez, R. (2018). Interactive life-history traits predict sensitivity of plants and animals to temporal autocorrelation. Ecol. Lett. 21, 275–286. doi: 10.1111/ele.12892

de Roos AM, Persson L. (2013) Population and Community Ecology of Ontogenetic Development (Monographs in Population Biology, 51). Princeton University Press, Princeton, NJ, USA.

Salguero-Gomez R, Jones OR, Jongejans E, Blomberg SP, Hodgson DJ, Mbeau-Ache C. et al. (2016). Fast-slow continuum and reproductive strategies structure plant life-history variation worldwide. Proc. Natl Acad. Sci. 113: 230-235.

Smallegange IM, Coulson T (2013). Towards a general, population-level understanding of eco-evolutionary change. Trends in Ecology & Evolution 28: 143-148.

Smallegange IM, Lucas S. 2023. DEBBIES to compare life history strategies across ectotherms. Preprint. https://doi.org/10.1101/2023.08.22.554265

Smallegange, I. M., Caswell, H., Toorians, M. E. M., and de Roos, A. M. (2017). Mechanistic description of population dynamics using dynamic energy budget theory incorporated into integral projection models. Methods Ecol. Evol. 8, 146–154. doi: 10.1111/2041-210x.12675