Brennen Fagan is a mathematical modeller at the University of York working at the Leverhulme Centre for Anthropocene Biodiversity and the Department of Mathematics to better understand the processes of biodiversity change. Before his current position, he received his PhD from York’s Department of Mathematics for his thesis on Quantifying War: From the Battle of Britain to Terrorism. Brennen received his undergraduate degree at California State University, Fresno, with the Smittcamp Family Honors College.

Brennen is interested in using mathematical models to understand the social and biological world around us. In his PhD, this meant trying to understand historical processes and decision making, including the (in)famous decline of violence hypothesis. In his current role, Brennen has published on how dispersal affects biodiversity change, on how the microbiome might have created selection pressure favouring maternal transmission, and on how land use has a complicated, but often positive, relationship with pollen diversity. Brennen is also interested in interdisciplinary work especially around characterising past and fictional ecologies and understanding implicit biases in our scientific techniques and how our past, fiction, and tools relate to how we perceive and what we know about biodiversity. 

Currently, Brennen’s main line of research is in characterizing how a model responds to land use change in order to replicate observational studies done in the field. The main aim is to understand how different analyses across and through time and space affect our perceptions of biodiversity change. If two analyses are attempting to study the same phenomenon, we should naively expect that they give similar results, but this may not be the case with implications for what is the “right way” to measure biodiversity. 

Brennen is also involved in multiple ongoing collaborations. These include examining how history has shaped our perceptions of biodiversity, ecological and evolutionary feedbacks in host-microbiome co-evolution, and time series analysis of the relationship between human society and pollen diversity across time. Brennen also is involved in three upcoming PhD projects looking at incorporating historical processes into modern decision making for biodiversity and ecosystem services.