RESEARCH THEME | Assessing the impact of Global Change on Ecological Stability
Supervisor: Dr. Ian Donohue (Trinity College Dublin)
My PhD is with Ian Donohue at Trinity College Dublin. Together, we are going to investigate how global change is affecting ecological stability and see if we can find general rules about ecological responses to global change (e.g. climate change, urbanisation). This is all vague at the minute since we are yet to finalise the details of the several sub-projects that will ultimately make up my doctoral research.
Investigating the impact of Disturbance and Seasonality on Temporal Asynchrony
Collaborators: Dr. Ian Donohue (Trinity College Dublin), Dr. Evan Economo (Okinawa Institute of Science and Technology)
In collaboration with the Biodiversity and Biocomplexity Unit at the Okinawa Institute of Science and Technology, this project aims to investigate the spatiotemporal patterns of disturbance and community regulation using a multi-taxon approach. We hope to combine multiple aspects of the OKEON-Churamori project‘s sampling techniques to get a holistic view of bird and insect communities across Okinawa’s urban-rural gradient over time to investigate whether disturbance and seasonality interact to influence the community dynamics of Okinawa’s sub-tropical ecosystems.
Recognising and Reconceptualizing Regime Shifts in Ecology
Collaborators: Qiang Yang, Dr. Ian Donohue (Trinity College Dublin)
Regime shifts – i.e. critical transitions, i.e. alternate stable states etc. – are a popular concept in ecology, frequently forming the basis of top-level ecological research. But often studies of regime shifts (or equivalent) do not explicitly define the conditions behind reported changes in the ecosystem. We aim to address this by considering the various definitions of regime shifts and categorising published research into those studies which do or do not provide enough evidence for a regime shift as would be described by the most widely-used or most accurate definition.
Nature-based Solutions: Future Directions
Collaborators: Cian White, Dr. Ian Donohue, Prof. Jane Stout (Trinity College Dublin)
Nature-based Solutions are being implemented as a means of futureproofing our urban environments in particular, against global change. This project aims to suggest future directions for the implementation of successful Nature-based Solutions. It will highlight the need for evidence-based policy and will suggest some key areas of ecology which may help to inform Nature-based Solution research in coming years.
Patterns of Avian Biodiversity across Trophic Groups for an Island Archipelago
Collaborators: Dr. Nick Friedman, Julia Janicki, Dr. Evan Economo (Okinawa Institute of Science and Technology)
In collaboration with researchers at the Okinawa Institute of Science and Technology, I aim to explore the drivers of avian biodiversity across the Ryukyu archipelago. We want to determine the extent to which different components of biodiversity (e.g. taxonomic vs. phylogenetic vs. functional diversity) are equally or unequally influenced by classical biogeographic drivers and the degree to which these patterns vary by trophic group. We are using a big data approach to these questions based on maximum island occupancy scenarios.
RESEARCH THEME | Ryūkyū Soundscapes: Bioacoustic Monitoring across an Island Urban-Rural Gradient
Collaborators: Dr. Nick Friedman, Dr. Masashi Yoshimura, Kenneth Dudley, Dr. Evan Economo (Okinawa Institute of Science and Technology)
We are currently operating a landscape-scale sensor network to monitor the diversity, behaviour, and phenology of the Ryūkyū fauna. We collect thousands of hours of acoustic recordings each week and curate them using machine learning approaches for automated species detection and soundscape analysis. Our aims are: 1) to understand acoustic niche ecology across taxa, 2) to describe the impact of human disturbance on species distributions and behaviour, and 3) to curate a soundscape archive for collaborative research in ecology and evolution. First paper published in Ecological Research. Read about this work in the press here.
RESEARCH THEME | The Diversity of Forest Ants in Natural and Human-modified Environments in East Africa
Collaborators: Dr. Francisco Hita Garcia, Dr. Georg Fischer (Okinawa Institute of Science and Technology), Dr. Marcell Peters (University of Würzburg)
I am collaborating with researchers at the Okinawa Institute of Science and Technology and principal investigator Marcell Peters at the University of Würzburg in Germany, to determine the effect of habitat degradation and land-use change on biodiversity of ants in Kakamega forest, Kenya. We’re looking at the influence of land-use and agriculture on the taxonomic diversity of rare and abundant species, trophic ecology and food chain length, functional diversity and indicator species.
Drivers and Impacts of Indirect Social Learning in a Globally Invasive Fish (Poecilia reticulata)
Collaborators: Dr. Amanda Bretman, Dr. Sarah Zylinski (University of Leeds), Paula Tierney (Trinity College Dublin)
Guppies (Poecilia reticulata) are a globally invasive freshwater fish. Their invasion success is remarkable and widely studied, as is their social learning ability; that is, their ability to learn by interacting with another animal or its products. Guppies can learn from each other and from other species – a finding that has implications during the invasion process. We want to expand on previous work in invasion and behavioural ecology to ask whether there are any behavioural or morphological traits which may predict the learning success of certain individuals in the laboratory, and hence their potential to survive and thrive during the invasion process in the wild.
Incorporating Intraspecific Trait Variation into Functional Diversity: a case study of Birds in Borneo
Collaborators: Prof. Keith Hamer, Dr. Chris Hassall, Dr. Will Hoppitt, Felicity Edwards (University of Leeds), Dr. David Edwards (University of Sheffield)
This work aims to address the issue of using functional diversity measures that incorporate information at the individual scale. Data limitations (computational intensity, lack of appropriate diversity metrics, and data availability) often hamper high-resolution functional diversity studies, so we’re working on a method of overcoming these issues by using simulations and calculating the confidence that can be placed in the resulting outputs. This method acknowledges that simulation models of functional diversity aren’t perfect but quantifies the degree to which we can be confident in their outputs and hence in their usefulness for informing conservation. Published in Methods in Ecology and Evolution. Read more about this project on the Methods.blog.
The Value of Climate Envelope Modelling in assessing Species Responses to Climate Change
Collaborators: Prof. Keith Hamer (University of Leeds)
Abstract: Rapid climate change is occurring on a global scale, with species responses including range shifts, contractions and extinctions. It is vital that ecologists are able to quantify the effect of climatic changes on biodiversity and predict likely future impacts in order to inform conservation management decisions. Climate envelope modelling involves fitting species occurrence data to bioclimatic variables so as to produce ‘climate envelopes’ that represent species’ climatic niches. Increasingly, Climate Envelope Models (CEMs) are being developed to produce dynamic projections of species responses to future climate change. Whilst not without limitations, CEMs are valuable tools for monitoring global change in species distributions. Techniques for model selection and evaluation are outlined, and the caveats of current modelling techniques (termed ‘the limited paradigm’) are discussed. A comprehensive literature review reveals no single modelling technique that consistently outperforms any other, so recommendations are made for an ‘expert opinion’ scenario-based approach, whereby modelling techniques are selected depending on the desired outcome. Finally, suggestions for a shift towards increased resolution, standardisation, and hybridisation of climate envelope models are presented, with a focus on increasing biological realism of models while challenging the limited paradigm in order to more reasonably predict the impacts of future climate change.
Shifting Paradigms in Ecological Network Theory: Understanding Network Stability and Complexity
Abstract: This project was a synthesis essay under a theme entitled ‘Grand Challenges in Ecology.’ This involved a large literature search and review of a topic deemed to be of importance for current and future global ecological research. I chose to review current understanding of ecological networks, and transdisciplinarity in this field through synthesis of ecological network research on different levels of biological organisation, including population, spatial, community, and social networks. Finally, I discussed the possible applications of network theory, as well as unresolved questions in network ecology and possible future directions for this fascinating and multifaceted field.
This project was highly commended at the international undergraduate awards in 2015.
Biotic and Abiotic Drivers of Differential Defence Strategies across Habitats in the Obligate Myrmecophyte, Acacia drepanolobium
Abstract: Resource allocation theory focuses on the trade-off between investing resources in growth, reproduction and defence. In African savanna ecosystems which often have high rates of herbivory, plants must find ways to combat herbivores ranging from insects to giraffes. Plant defences come in various forms including physical structures (e.g. spinescence), toxicity and indirect defences. Here, I measure investment in two forms of defence by the obligate myrmecophyte, Acacia drepanolobium in an African savanna system (Laikipia, Kenya). I measure thorn length, domatia volume – an indirect measure of investment in defence by symbiotic acacia ants – and density of thorns and domatia for plants in their core, black-cotton and marginal, red clay habitat. I find that A. drepanolobium differs in defence strategies by habitat, investing more in thorns in marginal habitats, possibly in response to higher rates of herbivory and competition. In black-cotton systems where A. drepanolobium forms a near-monoculture and is less exposed to herbivory, individuals invest more in supporting ant symbionts in response to spatiotemporally heterogeneous herbivory. I propose that differences between biotic and abiotic factors lead to differential regulation in these habitats, with marginal habitats being limited top-down by herbivory, whilst individuals in black-cotton habitats face bottom-up resource limitation.