Dr. James Orr

Theoretical Ecology | Freshwater Ecology | Microbial Ecology



Responses of ecological communities to stressors

Hello there! I’m an ecologist interested in how stressors impact the diversity, stability, and functioning of ecological communities. I’m particularly interested in the interactions between species that lead to complex dynamics and in the interactions between multiple stressors that make predicting global change impacts so challenging.

I use a combination of mathematical theory, experimental ecology, and research synthesis in my work. Although much of my research focuses on fundamental questions in theoretical and community ecology, I am also interested in applied questions in the fields of global change biology, (freshwater) environmental science, and microbiology.

I was recently awarded a Discovery Early Career Researcher Award from the Australian Research Council to study how the temporal synchronization of antibiotics and phages impacts the ecology of bacterial communities and the evolution of antimicrobial resistance.

On this website, you can find a list of my publications (categorized by topic) and a collection of resources that I’ve produced for other scientists to use.


Experience

ARC DECRA, Independent Fellowship

University of Queensland, Australia, 2025 - 2028

My research project will leverage novel ecological theory to understand how the temporal synchronization of antibiotic and phage exposure influences the ecology and evolution of bacterial communities. I will be hosted in Dr. Andrew Letten’s microbial ecology research group. I will also work closely with Dr. Siobhán O’Brien at Trinity College Dublin and Dr. Jeremy Barr at Monash University.

Postdoctoral Researcher

University of Queensland, Australia, 2024 - 2025

I am a member of Dr. Andrew Letten’s microbial ecology research group. I am working on questions in fundamental ecology using theory (e.g., consumer-resource modelling, coexistence-theory) and experimental microbial ecology (e.g., using chemostats).

Postdoctoral Researcher

University of Oxford, UK, 2021 - 2024

I worked in Dr. Michelle Jackson’s aquatic ecology research group on the project: “Cumulative impacts of multiple stressors: improving temporal and biological realism”. I used ecological theory, freshwater mesocosm experiments, ecological modelling, and synthesis approaches to study multiple stressor impacts, with a particular focus on the temporal dynamics of stressors.

PhD in Theoretical Ecology

Trinity College Dublin, Ireland, 2018 - 2021

My PhD thesis was on the mechanisms of stressor interactions. I studied mathematical and theoretical ecology, multiple-stressor research, and freshwater ecology under the supervision of Dr. Jeremy Piggott, Dr. Andrew Jackson, and Dr. Jean-François Arnoldi.