William Jia-Ang Ou

About

Hi, welcome!

I'm an ecologist and PhD student working out of the Germain lab at UBC. Although trained as a biologist, my interests are extremely broad. This is because, at the root of it all, I'm deeply fascinated in the nature of complexity. Put simply, complexity can be anecdotally captured by the phrase: the whole is greater than the sum of its parts. In more jargony terms, it's the apparent separation between the microstates and macrostates of a system. This suggests that conventional reductionist approaches, of which we are so used to in science, may offer little to our investigations. It's not unlike trying to clap your hands underwater! As you may have noticed, complexity is everywhere, but it is particularly abundant in living sytems - systems that despite the inevitability of entropy increase, manages to maintain itself out-of-equilibrium. We see it in our economy, our society, the internet, the climate, and even in our bodies (the collection of cells and microorganisms that make up us!). My premise is that all these things are the result of biological processes governed by the ecologies of organisms and their environment, which have been and continue to be sculpted by Darwinian evolution. If this premise holds, I believe ecology and evolution offers endless opportunities for scientific discovery and allows us to get a glimpse of the inner workings of nature herself.

For my PhD research, I'm trying to understand how ecologically-similar species coexist. Coexistence of similiar species is a paradox because one of the central tenet of competition theory is that stable coexistence is permitted only when competiting species occupy different niches. The standard response to this paradox is that there are unobserved/cryptic envrionmental variability that promotes coexistence, emphasizing the role of exogenous envrionmental factors in determining species persistence. I would like to explore an alternative (but compatible!) explanation: that the environment that promotes persistence are, in part, shaped by activities of the organisms that inhabit it. How? My hypothesis is that the answer lies in information. Unlike inanimate objects, organisms have the capacity to sense their envrionment, find regularities in it, and act upon it to guide adaptive behaviour. In this way, organisms are not fully constrained by their environment, they have the capacity to modify it and alter how they experience it. As the late evolutionary biologist Richard Lewontin puts it:

I occasionally write/blog about things: 1) Simulating ecology 2) Predator-Prey, 3) Biology computing, 4) Ideas that need retiring

Research

* - Equal contribution
† - Shared senior authorship
^🌱︎ - Undergraduate mentee

Ecological memory induces transient cycles

A characteristic feature of living systems is that they leave traces of their existence in the environment. To investigate the consequences of these persistent environmental modifications on population dynamics, we modified an existing population model, derived some analytical properties, and evaluated it by fitting it to experimental data. We found that ecological memory induces novel transient behaviour and stabilises populations by reducing the parameter space in which chaotic dynamics occur. Fitted to time-series data of competing Tribolium beetles, the memory model clearly outperformed its memoryless counterpart — suggesting that these environmental legacies are not only dynamically consequential, but that ignoring them can bias our inference about population dynamics.

Ou, WJ-A, ^🌱︎Catherine Laver, ^🌱︎Seth Perez, Germain, RM, T. 2026. Ecological memory generates transient dynamics that bias empirical estimates of demographic parameters. The American Naturalist (Submitted)

Transient invaders modify resident metapopulation size

Species interact not only within local communities but also through regional-scale processes, yet such local–regional feedback in shaping metapopulation dynamics has rarely been tested experimentally. Using nectar microbes as a model system, we examined how a bacterial species dispersing into a sink habitat, sustained by external supply, interacts with a resident yeast both directly, by modifying local nectar chemistry, and indirectly, by altering metapopulation connectivity. We found that external bacterial supply enhanced local yeast productivity, and that this benefit was amplified when yeast dispersal was reduced in supplied patches. Analysis of a metapopulation model shows that bacteria-induced dispersal bias increases yeast metapopulation size by bringing the yeast metapopulation closer to its ideal free distribution. Together, our results underscore the role of dispersal in shaping how metapopulations experience density dependence across heterogeneous landscapes and highlight the relevance of material flows across ecosystem boundaries.

Ou, WJ-A, ^†Germain, RM, ^†Fukami, T. 2026. Transient invaders can increase resident metapopulation size by modifying local conditions and regional connectivity. The American Naturalist (Revisions submitted)

Spatial metastability of alternative stable states

Ecological communities often exhibit alternative stable states, where the outcome of community assembly is historically contingent. In a spatially extended system, multiple distinct alternative states can fix in different locations and therefore maintain regional diversity. Theory predicts, however, that dispersal between communities will homogenize the landscape, causing the metacommunity as a whole to drift toward one of the alternative states. Inspired by earlier works on sympatric speciation (e.g., Maynard Smith 1966), we conducted in silico experiments to examine how assortative dispersal — the tendency of individuals to disperse toward locations where conspecifics are more common — alters the persistence of alternative stable states at the metacommunity level. Just as assortative mating maintains sufficient segregation between incipient species for speciation to proceed, spatial extent and assortative dispersal can together create a metastable state in which alternative states coexist regionally over ecologically relevant timescales.

Ou, WJ-A, Germain, RM. 2026. Assorative dispersal faciliates the regional maintenance of alternative stable states. Ecological Monographs (In revision)

Writing accessible theory in Ecology and Evolution

Science operates on a heatlhy feedback between theory and experimentation. However, theories are often formalized in the form of mathematics, which render them inaccessible to those lacking formal training. In this paper, we outline a list of recommendations, based on Cognitive Load theory, that provides theoreticians concrete ways in which they can make their work more acceesible, thereby strengthening the link between theory and experimentation.

*Ou, WJ-A, *Henriques, GJB, Senthilnathan, A, Ke, P-J, ^†Grainger, TN, ^†Germain, RM. 2022. Writing Accessible Theory in Ecology and Evolution: Insights from Cognitive Load Theory. BioScience. [paper]

Paddy field agroecology

1. Trophic interactions with stable isotopes

Due to their low prey specificity, generalist arthropod predators are often neglected as potential biocontrol agents in agro-ecosystems. Furthermore, their inconspicuous feeding habits can be hard to quantify under field conditions. To overcome this limitation, we use stable isotope analysis, which provides time-integrated dietery information, to shed light on the inconspicuous trophic interactions betweeen generalist predators and their prey. As expected, generalist predators shift their diets over the course of the cropping season and these trends were consistent across different farming systems.

Hsu, G-C, Ou, J-A, Ho, C-K. 2021. Pest consumption by generalist arthropod predators increases with crop stage in both organic and conventional farms. Ecosphere. [DOI]

2. Arthropod biodiversity across scales

Agro-ecosystems are complex dynamic mosaics where environmental heterogeneity vary across spatial scales. Moreover, species can differ in their responses to environmental conditions of varying spatial scales, which ultimately affects the diversity and composition of ecological communities. In this study, we show that paddy field inhabiting arthropods show only weak responses to local factors such as organic farming and crop height. In contrast, most species show strong positive responses to forest cover in the surrounding matrix. These general responses were true even for species of different trophic groups.

Plant-animal interactions

1. Effects of plant water stress on multitrophic arthroprod communities

The association between drought and insect outbreaks is a well-documented phenomenon but its generality across other plant-insect herbivore systems remains unknown. In this study, we conducted a field experiment showing that the impact of water stress on herbivore performance is highly dependent on animal community and species interactions. Specifically, the negative effects of plant water stress on Pierid larvae performance was the result of species interaction (competition and predation) and not changes in plant quality. Read more here:

*Lin, P-A, *Liu, C-M, *Ou, J-A, Sun, C.-H., Chuang, W.-P., Ho, C.-K., Kinoshita, N., & Felton, G. W. (2021). Changes in arthropod community but not plant quality benefit a specialist herbivore on plants under reduced water availability. Oecologia. [DOI]

2. Direct and indirect effects of warming and predation on aphid population dynamics

Natural ecological communities contain multiple interacting species. As such, impacts of environmental change can be hard to predict because environmental change can affect species both directly and/or indirectly through species interactions. In this study, we applied structural equation modeling to decompose the direct and indirect effects of experimental warming on aphid population dynamics in a lady beetle-aphid-soy bean tri-trophic system. Our preliminary results show that plant-mediated indirect effects were negligible and that warming affected aphid population dynamics mainly through direct effects on intrinsic growth rate and alate/apterous ratio

CV

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Contact

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Elements

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