WHAT WE DO
The experimental ecology & conservation group focusses on synthesising information from mathematical models, small-scale experimental systems, and long-term wild population data to learn more about the world around us, and in particular help make decisions about how to best preserve biodiversity into the future.
A specific focus is on developing new, exciting, and useful techniques to make the experimental systems we work with more realistic reflections of the world around us.
ITS ALL ABOUT THE BIG PICTURE
But our focus is always on how we can learn more about the natural world without having to carry out invasive or damaging experiments in the field.
EARLY WARNING SIGNALS
Predicting the fate of biological systems is critical in the light of continued global change, especially in the field of conservation biology where at risk populations must be prioritised to make the most of limited resources. A long running interest of this group is developing warning signals of approach population, community, and ecosystem collapse based on temporal patterns in abundance, trait, and spatial data.
EXPERIMENTALLY TESTING CONSERVATION THEORY
Designing optimal conservation strategies is key in the face of limited funding and ever increasing anthropogenic stresses. A central theme to the group is using experimental systems to test and develop conservation theory.
As climate changes species are increasingly at risk of extinction as they fail to move fast enough to stay within their ecological niche. One radical option is to relocate them outside of their historic range to ensure their medium to long term survival. We are interested in how and when such moves should be undertaken, and how a move will affect the resident communities.
THE EFFECTS OF MULTIPLE STRESSORS
The effects of multiple stressors (e.g. including habitat loss, pollution, over harvesting, climatic change, and the introduction of invasive species) on global biodiversity is a continued concern. We are interested in the possible interactive effects of these stressors, and how this may affect populations and communities.
RESILIENCE AND RECOVERY IN FISHERIES
Fisheries are one of the most economic and ecologically important ecosystems on earth. However the vast majority are in a state of significant degradation. We are interested in how such systems might recovery, and the pathways they might take doing so, and how these pathways affect community structure and function.
DR CHRIS CLEMENTS
I did my Ph.D. University of Sheffield, UK, spent time as a post doc at the University of Zürich and University of Melbourne. My interests centre on the extinction of species and collapse of populations, topics which I investigate using a combination of mathematical models, microcosm experiments, and analysis of real world population data.
My current work focuses on developing and testing early warning signals of population collapse, with a view to predicting regime shifts prior to their occurrence.
2018 onwards - Lecturer, University of Bristol
2017 to 2018 – SNSF fellow, the University of Melbourne
2014 to 2017 – Postdoc, the University of Zürich
2010 to 2014 – Ph.D. student, University of Sheffield
2007-2010 - BSc Ecology, University of Sheffield
PhD student (University of Zurich)
I am investigating how populations respond to different environmental perturbations and if there are any early warning signals associated with population regime shifts. To achieve this, I am using a combination of simulation-based modelling approach and experimental methods involving laboratory microcosms. My previous research was based on how variation in a particular trait can result in coexistence in different tree species. In my current work, also, I am using a trait-based approach to better quantify and hopefully predict the impact of environmental change on populations and ecological communities.
Co-supervised with Prof. Arpat Ozgul.
PhD student (University of Bristol)
My previous research was based on the effect of experimental warming on insect community in Tibetan plateau. Now I am studying the efficiency of wildlife corridors in theory and in practice. I am interested the role of corridors in determining the population growth and stability in microcosm networks and under field conditions, testing whether changing the quality and quantity of corridors can influence population dispersal ability and enhance ecosystem functions. My research would have a better understanding of the importance of wildlife corridors in fragmented habitats.
Co-supervised with Prof. Jane Memmott.
I am interested in the use of long-term wild population records in conjunction with other databases concerning climate and life histories, to analyse the aggregate and emergent traits that influence relative vulnerability of species to anthropogenic stressors including climate change, habitat loss, pollution, over harvesting and the introduction of invasive species. Also of interest is the relative importance of each stressor and potentially how synergistic interactions are contributing to the sixth mass extinction. The aim of the research is to inform policy makers, allowing them to develop, prioritise and deliver effective conservation strategies.
My research interests focus on the importance of land management practices for species conservation on a multi-species level. During my undergraduate studies I created a spatially explicit model using NetLogo to investigate the effects of habitat fragmentation and wildlife corridors on predator-prey population dynamics. My future research will involve using microcosm experiments to investigate the SLOSS debate, in particular whether species dispersal between patches affects what the best land-management practice is, and how our inability to detect species in heterogeneous environments might alter our decision-making process.
Baruah, G., Clements, C., Ozgul, A. Eco-evolutionary processes underlying early warning signals of population decline. Journal of Animal Ecology, in press.
Clements, C., McCarthy, M., Blanchard, J. Early warning signals of recovery in complex systems. Nature Communications, in press.
Recommended by F1000
Baruah, G., Clements, C., Guillaume, F., Ozgul, A. When do shifts in trait dynamics precede population declines? The American Naturalist, 193, pp. 633–644.
Clements, C., Ozgul, A. Indicators of transitions in biological systems. Ecology Letters, 21, 905-919.
Recommended by F1000
Clements, C., Blanchard, J., Nash, K., Hindell, M., Ozgul, A. Reply to ‘Whaling catch data are not reliable for analyses of body size shifts’, Nature Ecology & Evolution, 2, 757–758.
Clements, C., Blanchard, J., Nash, K., Hindell, M., Ozgul, A. Body size shifts and early warning signals preceded the historic collapse of whale stocks. Nature Ecology & Evolution, 1, 188.
Carlson, C., Burgio, K., ... Clements, C., ... , Getz, W. (2017). Parasite biodiversity faces extinction and redistribution in a changing climate. Science Advances, 3, e1602422.
Weissman, T., Davies, K., Clements, C., Melbourne, B. Estimating extinction risk with minimal data. Biological Conservation, 213, 194-202.
Brooks, M., Clements, C., Pemberton, J., Ozgul, A. Estimation of individual growth trajectories when repeated measures are missing. American Naturalist, 190, 377-388.
Pimiento, C., Griffen, J., Clements, C., Silvestro, D., Varela, S., Uhen, M., Jaramillo, C. The Pliocene marine megafauna extinction and its impact on functional diversity. Nature Ecology & Evolution, 1, 1100.
Cizauskas, C., Carlson, C., Burgio, K., Clements, C., Dougherty, E., Harris, N., Phillips, A. (2017). Parasite vulnerability to climate change: an evidence-based functional trait approach.Royal Society Open Science, 4: 160535.
Clements, C., Ozgul, A. Rate of forcing and the forecastability of critical transitions. Ecology & Evolution, 6, 7787-7793.
Dougherty, E., Carlson, C., Bueno, V., Burgio, K., Cizauskas, C., Clements, C., Seidel, D., Harris, N. Paradigms for parasite conservation: adaptive approaches for a neglected target. Conservation Biology, 30, 724-733.
Pimiento, C., MacFadden, B., Clements, C., Velez-Juarbe, J., Jaramillo, C., Silliman, B. Geo- graphic distribution patterns of Carcharocles megalodon over time reveal clues about mechanisms of extinction. Journal of Biogeography, 43, 1645-1655.
Clements, C., Ozgul, A. Including trait-based early warning signals helps predict population collapse. Nature Communications, doi:10.1038/ncomms10984.
Clements, C., Drake, J., Griffiths, J., Ozgul, A. Factors influencing the detectability of early warning signals of population collapse. The American Naturalist, 186, 50-58.
DeLong, J., Gilbert, B., ..., Clements, C., ..., O'Connor, M. The body-size dependence of trophic cascades. The American Naturalist, 185, 354-366.
Palamara, G., Childs, D., Clements, C., Petchey, O., Plebani, M., Smith, M. Inferring the temperature dependence of population parameters: the effects of experimental design and inference algorithm. Ecology and Evolution, 4, 4567–4811.
McCarthy, M., Moore, A., Krauss, J., Morgan, J., Clements, C. Linking indices for biodiversity monitoring to extinction risk theory. Conservation Biology, 28, 1575-1583.
Pimiento C., Clements C. When did Carcharocles megalodon become extinct? A new analysis of the fossil record. PLoS ONE, DOI: 10.1371/journal.pone.0111086
Frantz, A., McDevitt, A., ..., Clements, C., ...., Burke, T. Re-visiting the phylogeography and demography of European badgers (Meles meles) based on broad sampling, multiple markers and simulations. Nature Heredity, 113, 443-453.
Clements, C., Collen, B., Blackburn, T., Petchey, O. Historic environmental change may affect our ability to infer extinction status. Conservation Biology, 28: 971–981.
Gilbert, B., Tunney, T., McCann, K., ..., Clements, C., ..., O’Connor, M. A bioenergetic framework for the temperature dependence of trophic interactions. Ecology Letters, 17, 902-914
Clements, C., Collen, B., Blackburn, T., Petchey, O. Effects of directional environmental change on extinction dynamics in experimental microbial communities are predicted by a simple model. Oikos, 123, 141-150
Clements, C., Warren, P., Collen, B., Blackburn, T., Worsfold, N., Petchey, O. Interactions between assembly order and temperature can alter both short and long-term community composition. Ecology & Evolution, 3(16): 5201–5208
Carlson, C., Cizauskas, C., Burgio, K., Clements, C., Harris, N. The more parasites, the better? Science, 342, p1041
Clements, C. Public interest in the extinction of a species may lead to an increase in donations to a large conservation charity. Biodiversity and Conservation, 22, p.2695-2699.
Clements, C., Worsfold, N., Warren, P., Collen, B., Blackburn, T., Clark, N., Petchey, O. Experimentally testing an extintion estimator: Solow's Optimal Linear Estmation model.Journal of Animal Ecology, 82, p345-354.
We are always looking for enthusiastic members to join the group, from masters students to post docs. If positions are available then then will be listed below. Please feel free to contact us any time if you are interested in being a part of our team.
To start Sept 2020
PHD STUDENTSHIP - ECOLOGICAL COLLAPSE IN FRESHWATER ECOSYSTEMS
We are looking for an excellent student to test and develop methods to predict the collapse of freshwater ecosystems. This project will use long term monitoring data from the Sea of Galilee along with size spectra modelling, so students with strong interests in statistical methods or modelling approaches are particularly encouraged to apply.
For more information see:
Full Project Description
Regime shifts, characterised by sudden, often irreversible, changes in the composition of biological communities, can have catastrophic impacts on the ecosystem services which society relies on. Classic examples of this phenomenon originate from freshwater ecosystems, where shifts in the structure of a community can lead to cyanobacteria-dominated ecosystems, with potential negative impacts on human and livestock health. Being able to predict impending regime shifts in time to avert them is consequently a critical goal with significant implications for the management of scarce freshwater resources. This project will use long-term monitoring data in combination with advanced modelling techniques to characterise how community composition can change prior to and during a regime shift, and test and develop generalisable methods to predict and prevent such shifts in the future. A key goal in predictive ecology is forecasting the potential for rapid changes in ecosystems, leading to the development of “early warning signals”. These are generalisable methods which aim to predict changes in the composition of a community by detecting signals in time series data which are symptomatic of an approaching regime shift. The potential efficacy of such signals has been widely shown in simulation studies, but remains largely untested on real-world data, in part due to the lack of long-term monitoring before and after observed regime shifts. This has raised questions about their suitability to inform management strategies for natural capital. This project will tackle this knowledge gap using a two-pronged approach: analysis of long-term monitoring data from a well-studied lake ecosystem which has undergone a regime shift, and complementary theoretical modelling of the lake community. The Sea of Galilee is the only natural freshwater lake in Israel, and consequently a key resource. Its importance has meant extensive monitoring has been carried out for nearly 50 years, providing exceptional data on the abundances, biomasses, and densities of fish, zooplankton, and phytoplankton species from 1969 until 2018, as well as changes in the lake’s chemical composition. The lake’s community underwent a major shift in 1994-1995, resulting in a severe deterioration in water quality and an increase in harmful algal blooms. Consequently, data on multiple species and trophic levels are available prior to, during, and after a known regime shift, making it ideal for testing and developing warning signal methods. These exceptional data will be used to parameterise a size-spectra model of the lake community, allowing multiple simulated outcomes of perturbations on the system to be assessed. This project will: (1) assess whether the regime shift in the Sea of Galilee could have been predicted prior to its occurrence, (2) determine how far in advance such warning signals are detectable, (3) examine whether it is better to focus on specific species, trophic levels, or look at the community dynamics as a whole when trying to predict a system’s future dynamics, and (4) identify what data should be collected in the future to predict regime shifts. In addition to the specialist training provided by the supervisors, the student will undertake a full range of general courses to enhance their employability and personal development, including training on Statistics, Computing, Research Ethics, Intellectual Property and Enterprise, Bioinformatics, Sampling Methodology, and Research Skills.