How Network Theory Can Prevent Extinctions
https://www.technologyreview.com/s/423282/how-network-theory-can-prevent-extinctions/
In what might be considered one of the most controversial applications of network and graph theory, Northwestern University in Illinois professors Sagar Sahasrabudhe and Adilson Motter have come to the conclusion that human involvement could in fact help to save species from extinction in certain ecosystems. On a small scale, we can use network theory to explain the relationships between different species within an ecosystem and create food chains from there. From there, it’s easy to see how great an imbalance within a certain species can effect those that are within the same ecosystem. Consider a scenario where a species of field mouse spreads a disease and wipes out 90% of their population. As a result, the relative predatory owl population will also begin to diminish a great deal. Alternatively, if a disease were to spread amongst a group of predatory owls, the field mouse population would no longer have as many predators to keep their numbers down and would increase drastically. From there, they could consume a much greater biomass of vegetation and begin to impact other species within their ecosystem. When we look at a more complex ecosystem such as a marina, we find that many different prey and predator relationships overlap and interconnect with one another. In that, something that seems minor such as a deficiency in a plankton population could dismantle an entire ecosystem. Visual graphs or networks of such ecosystems can help to identify such problems, and as Sahasrabudhe and Motter point out, a bit of human involvement can help to stop these imbalance cascades before they actually damage the entire system.
Although this article does not touch on any of the specific topics we’ve discusses in class, it’s easy to see how network theory provides the entire foundation for Sahasrabudhe’s and Motter’s conclusion. In addition, although it was not touched on in the article, it’s interesting to think about the impact that a cascading population imbalance in a given ecosystem might have on a larger scale. If a top predator were to find itself on the brink of extinction with its prey’s population running rampant in turn, the prey’s population would eventually have to seek elsewhere to sustain its new size. This is one way that invasive species can ‘naturally’ occur (assuming there was no prior human interference to cause the imbalance in the first place). With this idea in mind, we can see how an imbalance in one ecosystem could eventually create a larger network across multiple ecosystems. The main difference in the food chain/ecosystem networks and the networks we’ve been talking about in class is the fact that food chains generally flow in one direction. In that, we miss out on making a lot of connections between some of the properties we’ve talked about in class and this article.
As it would turn out, humans are often times the primary cause for the imbalances within ecosystems to begin with, so it’s easy to make the case that we should be the ones to help set things back in order. However, this raises an ethical dilemma, so I’ll leave you with this question: should humans interfere with the ways of nature (regardless of prior human interaction) if it means saving a species from extinction for a certain area?