Figuring out why financial crises emerge in seemingly stable economies is tough. Widespread collapses are notoriously difficult to predict - to do so requires a comprehensive view of a complex, interconnected system. But help may be at hand: experts in finance are now looking to certain fields of ecology to help provide this viewpoint.
Ecologists have long been concerned with how connections between species relate to the overall stability of an ecosystem. Rather than focus on an individual species, some use a powerful branch of mathematics called network theory to map out a web of interaction. These networks can then be compared to one another to provide insights into how an ecosystem might cope with external shocks. Depending on the network’s structure, even a small change can threaten an entire system.
For example, in the 1940’s a drought-resistant plant native to Africa and Asia known as Buffelgrass was introduced to the south-west America’s Sonoran Desert as a means of feeding cattle. Although the hardy grass initially seemed benign, it soon began displacing native species of flowering cacti. This triggered a destructive feedback loop: as populations of pollinators (such as the Rufous Hummingbird) began to suffer, damage to the flowering cacti accelerated. Within a few decades, these harmful impacts had spread and multiplied over a broader network of pollinators and plants.