Upon establishing the Environmental Resilience Institute (ERI) at Indiana University, the leaders and visionaries reported four main goals. The first goal stated that the supported research would create “accurate predictions about coming changes in weather patterns, water, plants and animals, and disease risk.” This goal focused on directly predicting what Hoosiers would have to face, such as economically-costly extreme weather conditions or an increase in tick-borne diseases. Equally important, the ERI wanted to create predictions about biodiversity, an indicator of the health of an ecosystem that provides countless services to society.
Enter Dr. Jason Bertram, a theoretical biologist.
A theoretical biologist is a scientist who uses mathematical models or applied equations to answer modern ecology and evolution questions. Bertram started his career with a focus in math and physics; but, after deciding he was more interested in biology and its application to environmental change, he used his expertise in modeling to focus on problems in ecology and evolution. It might seem impossible that math could answer any questions related to preserving something as large as biodiversity. But to preserve biodiversity, we need to better understand what determines the survival of a species and the role that interactions between populations of different species play in the ecosystem. Mathematical theory has been applied to evolution questions (e.g., the effects of mutations on fitness, predator-prey co-evolution) for decades, so quantitative models can be used to make predictions about how populations will respond to changes in their environment.
Presently, we are living in the anthropocene, a term used to describe the current geologic age in which humans predominately affect the environment. Humans have greatly altered their surrounding environment, from habitat destruction to emission of greenhouse gases. But, inconsistency in weather conditions and dynamics within an ecosystem isn’t new for planet Earth. “I come from Africa,” explains Bertram, “where ecosystems are less constant [and they regularly face] fire, big herbivores that [destroy foliage], and droughts. [So, while] humans are having a great effect on the ecosphere, it’s not going to fall apart. But, it’s probably going to look different.” Bertram is interested in exploring what aspects of human impacts on the environment are unnatural in an already dynamic world. Specifically, what is so distinct about the way humans are affecting ecosystems?
To address this question, Bertram and other theoretical biologists need to better understand how an ecosystem can be disturbed. “For example, it’s different if you indiscriminately kill all sizes of fish in a population versus always taking the biggest fish,” explains Bertram.
Bertram is currently studying the possibility that populations in “indiscriminately” disturbed environments have greater genetic variance. This phenomenon may occur because disturbance reduces competition within a population. When competition is high, only the “best adapted” can survive. But, when an environment is disturbed, we might see “creative destruction.” In other words, individuals with the best adaptations to survive in the environment prior to the disturbance might be eliminated or no longer have the best adaptations in the changed environment, leaving room for greater diversity. So, perhaps human disturbance won’t always be completely destructive. Bertram argues that the dynamics of an ecosystem are much more complicated than that and species will continue to adapt.
Unfortunately, empirical studies of disturbance aren’t close to being exhaustive. “Studies tend not to be as strong on species that are about to be wiped out, [but are more likely to be on] species that are doing fairly well,” says Bertram. However, models do not have these limitations. Rather than looking backward or studying species in current day, models create predictions that can be generalized to population responses to future disturbances. These responses can be simulated rather than measured before it’s “too late.” Bertram plans to continue to address these questions via quantitative models. By using the historic models designed around population evolution and ecosystem relationships, he can investigate how disturbances could facilitate adaptations when faced with human threats and how human disturbances differ from “natural ones”.
Acknowledgements: Thank you to Dr. Jason Bertram for allowing me to interview him about his work.
Edited by Evan Arnet and Ben Greulich