The complex algorithm that Google’s uses to rank web pages has been hailed by scientists as a way to predict extinction cascades within ecosystems. Huge complexity within ecosystems means that the current methods to plot the die offs which can lead from a single organism extinction are near impossible. With every species having a complex relationship with hundreds and sometimes thousands of others in its niche, combinations of all outcomes exceed the universes number of atoms.
Making small changes to the ‘PageRank’ algorithm, Dr Stefano Allesina, co-author of the study, realised he could use it for ecology. “First of all we had to reverse the definition of the algorithm. In ‘PageRank’, a web page is important if important pages point to it. In our approach a species is important if it points to important species,” he explained.
In addition, a cyclic element had to be incorporated to allow for the continuous pass of energy throughout the food web. “When an organism dies it goes into the detritus pool and in turn gets cycled back into the food web through the primary producers, the plants,” Dr Allesina explained. “Each species points to the detritus and the detritus points only to the plants. This makes the web circular and therefore leads to the application of the algorithm.”
WWF-UK’s director of programmes Dr Glyn Davis welcomed the research saying “Any research that strengthens our understanding of the complex web of ecological processes that bind us all is welcome.”
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