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.
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.
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.
The diversity of forest ants in natural and human modified environments in Kakamega, Kenya
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.
The influence of demonstrator and observer traits on indirect social learning in guppies
Collaborators: Dr. Amanda Bretman, Dr. Sarah Zylinski (University of Leeds)
There remains relatively little work on what influences indirect social learning in animal groups, that is, learning that is not directly learnt via animal teaching, but is still socially acquired because another animal’s actions or products influenced the learning of the focal individual. We’re using a second-order conditioning experiment to test the ability of guppies (Poecilia reticulata) to learn a light-food-reward association and socially transmit/ socially learn this information. We want to see whether there are any particular factors that influence indirect social learning in this system by correlating learning success with morphological and behavioural traits.
Incorporting intraspecific trait variation into functional diversity: a case study of birds of 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 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.
Functional Traits Explain Changes in Seabird Population and Distribution over a 40-year Period
Collaborators: Prof. Keith Hamer (University of Leeds)
Abstract: Functional traits are often overlooked when predicting species responses to climate change. It seems intuitive that the ability of a species to adapt to new environments should predict the likelihood of its continuation. Yet few long-term studies of populations or species range shifts take into consideration functional traits as predictors of vulnerability. Herein models are generated for predicting changes in population and distribution over the past 40 years of British seabird monitoring. The models consider functional trait differences between species with regard to feeding ecology, nesting habitat, clutch size, and latitudinal range. A clear ability of these models to explain the past 40-year population and distribution changes in British seabirds supports the focus of this study on functional traits as predictors of such change, thereby highlighting the need for further consideration of functional traits as drivers of population and distribution changes across a wider variety of taxa.
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 leads 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.