Fri, 30 Oct 2026
11:00 -
12:00
L4
Growth accelerations are the key to the niche
Dr Oliver Meacock
(School of Biosciences University of Sheffield)
Abstract
The relationship between organisms and their environment is the heart of ecology. Microbes exemplify this relationship, modifying their shared chemical environment to engage in cooperative exchanges, kill each other with deadly toxins and compete over limited resources. Understanding the environment-organism coupling - the topic of niche theory - is therefore key to manipulating microbiota.
Much of our understanding of the niche comes from rate-based frameworks. For example, resource competition is typically described using the logistic equation, which states that growth rates tend to zero as population densities increase toward their carrying capacity. The mechanisms driving these population dynamics are implicit, with the underlying resource dynamics abstracted out of the model.
Starting from mechanistically-explicit consumer-resource models, I will argue that growth accelerations (resulting from the combination of the timescales of both environmental and population dynamics) provide a more powerful understanding of the niche than rate-based perspectives. Exploiting an exact homology between the equations describing consumer-resource systems and the generalised Lotka-Volterra (gLV) model, I will demonstrate that basic concepts such as density-dependence and context-dependencies of interactions can be accurately captured with an accelerational lens. Moreover, derived frameworks such as Modern Coexistence Theory (MCT) can be readily translated into an accelerational form, enabling their integration into mechanistic frameworks. Finally, I will exploit this homology to explain how obligatory mutualistic exchanges between bacteria can be reconciled with ecosystem stability, contrasting with predictions from the gLV model.